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WORKS  OF  J.  A.  MANDEL 

PUBLISHED   BY 

JOHN  WILEY  &  SONS. 


A  Text^book  of  Physiological  Chemistry. 

By  Olof  Hammarsten,  Professor  of  Medical  and 
Physiological  Chemistry  in  the  University  of 
Upsala.  Authorized  translation,  from  the  second 
Swedish  edition  and  from  the  author's  enlarged 
and  revised  German  edition,  by  John  A.  Mandel, 
Assistant  to  the  Chair  of  Chemistry,  etc.,  in  the 
Bellevue  Hospital  Medical  College  and  in  the  Col- 
lege of  the  City  of  New  York.     8vo,  cloth,  $4.00. 

Handbook  for  Bio-Chemical  Laboratory. 

lamo,  cloth,  $1.50. 


,  1  UVtl 

A   TEXT-B0C)E:,;V  4>  i  /..U.1  uiii 


OF; 


PHYSIOLOGICAL  CHEMISTRY. 


OLOF   HAMMARSTEN, 

Professor  of  Medical  and  Physiological  Chemistry  in  the 
University  of  Upsala. 


g^utljori^cb  Cninshitiait 

FROM  TEE  AUTHOR'S  ENLARGED  AND  REVISED 
TUIRD   GERMAN  EDITION 


JOHN  A.  MANDEL, 

Professor  of  Inorganic  Chemistry  and  Physics,  and  Adjunct 

Professor  of  Physiological  Chemistry  in  the  University 

and  Bellevue  Hospital  Medical  College. 


SECOND    EDITION. 
FIRST   THOUSAND. 


NEW    YORK: 

JOHN   WILEY   &   SONS. 

London  •    CHAPMAN   &  HALL,   Limited. 

1898. 


H-lS 


pVright,  1898, 


Copi 

BY 

JOHN  A.  MANDEL. 


ROBERT    ORUMMOND,    PRINTER,    NEW    YORK. 


PREFACE  TO  THE  SECOND  GERMAN 
EDITION. 


Aftek  the  appearance  of  the  first  Swedish  edition  of  this  text- 
book I  was  asked  by  several  colaborers  abroad  to  provide  a  German 
translation,  which  was  at  that  time  impossible  for  several  reasons. 
Bnt  I  found  it  very  difficult  to  decline  a  similar  proposal  which  I 
received  from  many  colleagues  after  the  second  edition  appeared. 

I  yielded,  therefore,  to  their  expressed  wishes;  but  I  found  after 
a  time  that  it  was  impossible  to  obtain  a  translator  in  this  special 
province  of  science,  notwithstanding  the  unwearied  exertions  of  my 
publisher.  Nothing  remained  for  me  but  to  undertake  the  transla- 
tion myself;  hence  I  ask  the  reader's  indulgence  for  possible 
idiomatic  or  orthographic  errors. 

Specialists  will  at  once  perceive  that  the  book  before  them  is  not 
a  complete  or  detailed  text-book.  My  intention  was  merely  to  sup- 
ply students  and  physicians  with  a  condensed  and  as  far  as  possible 
objective  representation  of  the  principal  results  of  physiologico- 
chemical  research  and  also  with  the  principal  features  of  physio- 
logico-chemical  methods  of  work.  It  seems  to  me  that  I  have 
followed  a  common,  j)ractical,  even  if  not  strictly  correct  usage  in 
allowing  space  in  this  book  to  the  more  important  pathologico- 
chemical  facts,  although  I  have  given  the  book  the  title  Text-book 
of  Physiological  Chemistry. 

The  arrangement  of  subject-matter,  which  deviates  considerably 
from  that  generally  followed  in  text-books,  was  caused  by  the 
manner  in  which  physiological  chejnistry  is  studied  in  Sweden. 
Here  pliysiologico-  and  pathologico-chemical  laboratory  practice  is 
obligatory  on  all  students  of  medicine.  In  the  arrangement  of  such 
practical  work  I  continually  kept  in  view  that  it  should  not  consist 
of  isolated,  purely  chemical  or  analytico-chemical  problems,  bnt  that 
always,  as  far  as  possible,  it  should  go  hand  in  hand  with  the  study 
of  the  different  chapters  of  chemical  physiology. 

iii 


278224 


IV  PBEFACE. 

The  stadj  of  physiologico-chemical  processes  within  the  animal 
body  must  precede  the  stady  of  its  component  parts,  its  fluids  and 
tissues;  and  this  latter  study,  according  to  my  experience,  will  then 
only  inspire  true  interest  if  the  study  of  the  physiological  signifi- 
cance of  those  component  parts  be  closely  pursued  in  connection 
with  that  of  the  transformations  which  take  place  in  these  fluids 
and  tissues. 

In  view  of  this  arrangement  of  subject-matter,  and  in  order  to 
render  my  book  of  greater  interest  and  utility  to  those  who  do  not 
wish  to  take  cognizance  of  its  analytico-chemical  part,  I  have  dis- 
tinguished the  latter  by  different  setting  of  the  type.  "With  the 
exception  of  urinary  analysis,  which  practically  is  of  particular 
importance  and  which  has  been  treated  somewhat  elaborately,  this 
part  in  general  depicts  only  the  main  points  in  the  methods  of 
preparation  and  of  analytical  methods.  The  instructor  who  su- 
perintends the  laboratory  practice  and  who  chooses  the  problems 
for  work  has  ample  opportunity  to  give  the  beginner  the  necessary 
advanced  directions,  and  for  the  more  experienced  student,  as  well 
as  for  the  specialist,  the  excellent  works  of  Hoppe-Seyler, 
Neubauer-Huppert,  and  others  render  more  explicit  directions 
superfluous. 

Olof  Hammarstest. 

Upsala,  October,  1890. 


TRANSLATOR'S  PREFACE  TO  THE  FIRST 
AMERICAN  EDITION. 


Knowing  tlie  demands  of  the  medical  stadent  and  practising 
physician  for  a  more  extended  knowledge  of  physiological  chemis- 
try, and  at  the  same  time  knowing  the  lack  of  literature  on  this 
subject  in  the  English  language,  I  have  been  led  to  make  a  transla- 
tion of  this  most  admirable  work.  The  subject  of  physiological 
chemistry  is  being  more  and  more  advanced  in  this  country,  until 
it  will  soon  become  an  obligatory  study  in  our  medical  schools,  and 
the  enlargement  of  the  literature  on  the  subject  will  greatly  help  its 
progress. 

It  will  be  seen  at  a  glance  that  the  work  is  well  suited  as  a 
laboratory  book,  for  it  contains  the  best  methods  for  the  prepara- 
tion, detection,  and  quantitative  estimation  of  most  of  the  sub- 
stances found  in  the  organism  and  its  excretions  and  secretions. 
At  the  author's  request  I  have  made  no  additions  or  changes  what- 
soever in  the  manuscrijit,  and  it  may  seem  that  some  of  the  methods 
described,  especially  those  on  urinary  analysis,  are  too  lengthy  and 
troublesome  for  the  practising  physician;  however,  the  quick  or 
clinical  methods  are  well  described  in  smaller  handbooks  on  the 
subject.  In  the  work  of  translation  I  have  adhered  as  closely  as 
possible  to  the  author's  enlarged  German  edition  and  also  the  orig- 
inal Swedish  edition,  and  therefore  the  literary  errors  will  perhaps 
be  pardoned, 

I  must  here  express  my  appreciation  to  Mon.  A.  Bourgougnon, 
who  has  kindly  gone  carefully  over  the  manuscript  and  read  the 
proof-sheets. 

J.  A.  Mandel. 

New  York,  October,  1893. 

▼ 


PREFACE  TO  THE  THIRD  GERMAN 
EDITION. 


The  pre&ent  edition,  which  differs  from  the  second  in  the 
arrangement  of  matter,  contains  three  new  chapters.  The  wonder- 
ful development  of  our  knowledge  of  the  chemistry  of  the  carbo- 
hydrates in  recent  times  has  made  it  necessary  to  introduce  a  special 
chapter  on  this  subject ;  and  as  the  two  chief  groups  of  organic 
foods,  the  protein  substances  and  the  carbohydrates,  are  treated  of 
in  special  chapters,  the  third  group,  the  fats,  likewise  has  a  chap- 
ter devoted  to  it.  It  also  appears  appropriate  to  treat  the  rather 
extensive  subject  of  the  chemistry  of  respiration  in  a  special  chapter 
and  not,  as  heretofore,  in  connection  with  the  blood.  Another 
deviation  from  the  earlier  editions  is  that  the  present  edition  is 
supplied  with  the  references  to  the  literature,  in  pursuance  of  the 
request  made  on  many  sides.  This  edition  is  also  thoroughly 
revised  and  enlarged  according  to  the  advancement  of  the  science; 
still  it  was  naturally  impossible  to  incorporate  into  the  text  the 
various  papers  appearing  or  accessible  to  me  during  the  printing  of 
this  edition. 

Olof  Hammaksten. 

Upsala,  April,  1895. 


TRANSLATORS  PREFACE  TO  THE   SECOND 
AMERICAN   EDITION. 


As  the  subject  of  physiological  chemistry  has  been  rather 
generally  introduced  into  the  curricnlum  of  our  medical  schools, 
and  as  the  first  American  edition  was  one  of  the  few  authoritative 
works  on  this  imj^ortant  subject,  I  was  led  to  jDrepare  a  second 
American  edition  from  the  third,  revised,  German  edition.  At  the 
request  of  the  author  no  changes  or  additions  have  been  made  with 
the  exception  of  the  incorporation  of  the  author's  Addenda  into 
the  text. 

J.  A.  Mandel. 

New  York,  October,  1898. 

vii 


CONTENTS. 


CHAPTER  I. 

PAGE 

Iktroduction 1 

CHAPTER  II. 
Protein  Substances 17 

CHAPTER  III. 
Cabbohtdrates 59 

CHAPTER  IV. 
AyiMAii  Fats 81 

CHAPTER  V. 
The  AiTTMAT.  Cell 88 

CHAPTER  VI. 
The  Blood Ill 

CHAPTER  VII, 
Chyle,  Ltmph,  Transudations  and  Exudations 180 

CHAPTER  VIII. 
The  Liver 20G 

CHAPTER  IX. 
Digestion .  251 

CHAPTER  X. 
Tissues  of  the  Connective  Substance 342 

CHAPTER  XI. 

Muscle 360 

ix 


X  CONTENTS. 

CHAPTER  XII. 

FAOE 

Brain  and  Nerves 390 

CHAPTER  XIII. 
Organs  of  Generation 403 

CHAPTER  XIV. 
Milk 420 

CHAPTER  XV. 
The  Urine , 445 

CHAPTER  XVI. 
The  Skin  and  its  Secretions 573 

CHAPTER  XVII. 
Chemistry  op  Respiration 583 

CHAPTER  XVIII. 
Metabolism 607 


PHYSIOLOGICAL    CHEMISTRY. 


CHAPTEE  I. 

INTRODUCTION, 

It  follows  from  the  law  of  the  conservation  of  force  and  matter 
that  living  beings,  plants  and  animals,  can  neither  produce  new 
matter  nor  new  force.  They  are  only  called  upon  to  appropriate 
and  assimilate  already  existing  material  and  to  transform  it  into 
new  forms  of  force. 

Out  of  a  few  relatively  simple  combinations,  especially  carbon 
dioxide  and  water,  together  with  ammonium  compounds  or  nitrates, 
and  a  few  mineral  substances,  which  serve  as  its  food,  the  plant 
builds  up  the  extremely  complicated  constituents  of  its  organism, 
pi'oteids,  carbohydrates,  fats,  resins,  organic  acids,  etc.  The 
chemical  work  which  is  performed  in  the  plant  must  therefore,  in 
the  majority  of  cases,  consist  in  syntheses;  but  besides  these,, 
processes  of  reduction  take  place  to  a  great  extent.  The  vis  viva 
of  the  sunlight  induces  the  green  parts  of  the  plant  to  split  off 
oxygen  from  the  carbon  dioxide  and  water,  and  therefore  the  chief 
constituents  of  the  plant  contain  less  oxygen  than  the  material 
serving  as  food.  The  vis  viva  of  the  sun,  which  produces  this 
splitting,  is  not  lost;  it  is  only  transformed  into  another  form  of 
force — into  the  potential  energy  or  chemical  tension  of  the  free 
oxygen  on  the  one  side,  and  the  combinations  less  oxygenated,  pro- 
duced by  the  synthesis,  on  the  other  side. 

These  conditions  are  not  the  same  in  animals.  Thev  are 
dependent  either  directly,  as  the  herbivora,  or  indirectly,  as  the 
carnivora,  upon  plant-life,  from  which  they  derive  the  three  chief 
groups  of  organic  nutritive  matter — proteids,  carbohydrates,  and 


2  :  INTRODUCTION. 

fats.  ■  These  bodies,  of  which  the  protein  substances  and  fat  form 
-the'-cUi^fViTiass  of  the  animal  body,  undergo  within  the  animal 
organism  a  splitting  and  oxidation,  and  yield  as  final  products 
■exactly  the  above-mentioned  chief  components  of  the  nutrition  of 
plants,  namely,  carbon  dioxide,  water,  and  ammonia  derivatives, 
which  are  rich  in  oxygen  and  have  feeble  potential  energy.  The 
chemical  tension,  which  is  partly  combined  with  the  free  oxygen 
and  partly  stored  up  in  the  above-mentioned  more  complex  chem- 
ical compounds,  is  transformed  into  vis  viva,  heat,  and  mechanical 
work.  While  in  the  plant  reduction  processes  and  syntheses,  which 
are  active  in  the  conversion  of  living  force  into  potential  energy  or 
chemical  tension,  are  the  prevailing  forces,  we  find  in  the  animal 
body  the  reverse  of  this,  namely,  splitting  and  oxidation  processes, 
which  convert  chemical  tension  into  living  force  {vis  viva). 

This  difference  between  animals  and  plants  must  not  be  over- 
rated, nor  must  we  consider  that  there  exists  a  sharp  boundary-line 
between  the  two.  This  is  not  the  case.  There  are  not  only  lower 
plants,  free  from  chlorophyll,  which  in  regard  to  chemical  jsrocesses 
represent  intermediate  steps  between  higher  plants  and  animals,  but 
the  difference  existing  between  the  higher  plants  and  animals  is 
more  of  a  quantitative  than  a  qualitative  kind.  Plants  require 
oxygen  as  peremptorily  as  do  animals.  Like  the  animal,  the  plant 
also,  in  the  dark  and  by  means  of  those  parts  which  are  free  from 
chlorophyll,  takes  up  oxygen  and  elimiuates  carbon  dioxide,  while 
in  the  light  the  oxidation  processes  going  on  in  the  green  parts  are 
overshadowed  or  hidden  beneath  the  more  intense  reduction  proc- 
esses. Like  the  animal  the  fermentive  fungi  transform  chemical 
tension  into  living  energy  and  heat;  and  even  in  a  few  of  the  higher 
plants — as  the  aroidecB  when  bearing  fruit — a  considerable  develop- 
ment of  heat  has  been  observed.  The  reverse  is  found  in  the 
animal  organism,  for,  besides  oxidation  and  splitting,  reduction 
processes  and  syntheses  also  take  place.  The  contrast  which  seem- 
ingly exists  between  animals  aud  plants  consists  merely  in  that  in 
the  animal  organism  the  processes  of  oxidation  and  sjjlitting  are 
prevalent,  while  in  the  plant  those  of  reduction  and  synthesis  have 
thus  far  been  observed. 

WoHLER  '  in  1824  furnished  the  first  example  of  synthetical 
PEOCESSES  within  the  animal    organism.     He  showed    that  when 

'  Berzelius,  Leiirb.  d.  Chemie,  iibersetzt  von  Woliler,  Bd.  4.  Dresden,  1831. 
S.  376,  Anm. 


ANIMAL   OXIDATIONS.  8 

benzoic  acid  is  introdaced  into  the  stomach  it  reappears  as  hippuric 
acid  in  the  urine,  after  it  combines  with  glycocoll  (amido-acetic 
acid).  Since  the  discovery  of  this  synthesis,  which  may  be  ex- 
pressed by  the  following  equation, 

C,H,.COOH+NH,.CH,.COOH=NH(C,H,.CO).CH,.COOH+H,0, 

Beuzoic  acid  Glycocoll  Hippuric  acid 

and  which  is  ordinarily  considered  as  a  type  of  an  entire  series  of 
syntheses  occurring  in  the  body  where  water  is  eliminated,  the 
number  of  known  syntheses  in  the  animal  kingdom  has  increased 
<5onsiderably.  Many  of  these  syntheses  have  also  been  artificially 
produced  outside  of  the  organism,  and  numerous  examples  of 
animal  syntheses  of  which  the  course  is  absolutely  clear  will  be 
found  in  the  following  pages.  Besides  these  well-studied  syntheses, 
there  occur  in  the  animal  body  also  similar  processes  unquestionably 
of  the  greatest  importance  to  animal  life,  but  of  which  we  know 
nothing  with  positiveness.  We  enumerate  as  examples  of  this  kind 
of  synthesis  the  reformation  of  the  red-blood  pigment  (the  haemo- 
globin), the  formation  of  the  different  proteids  from  the  peptones, 
the  formation  of  fat  from  carbohydrates,  and  others. 

The  chemical  processes  in  the  animal  body  we  have  mentioned 
above  as  consisting  chiefly  of  oxidation  and  splitting  processes. 
Tlie  oxygen  of  inhaled  air,  as  also  that  of  the  blood,  is  now  called 
neutral,  molecular  oxygen,  and  the  old  assumption  that  ozone 
occurs  in  the  organism  has  now  been  discarded  for  several  reasons. 
There  are  but  few  substances  which  can  be  oxidized  within  the 
animal  organism  by  the  neutral  oxygen;  while,  on  the  contrary, 
proteids  and  fat,  which  form  the  chief  part  of  the  organic  constit- 
uents of  the  animal  body,  are  almost  indifferent  to  neutral  oxygen. 
The  question  arises,  how  then  is  the  oxidation  of  these  and  other 
bodies  possible  in  the  animal  organism  ? 

Formerly  the  view  was  generally  accepted  that  animal  oxida- 
tion took  place  in  the  fluids,  while  to-day  we  are  of  the  opinion, 
derived  from  the  investigations  of  Pfluger  and  his  pupils,'  that  it 
is  connected  with  the  form-elements  and  the  tissues.  The  question 
how  this  oxidation  in  the  form-elements  proceeds  and  how  it  is 
induced  cannot  be  answered  with  certainty. 

'Pfluger.  Pfliiger's  Arcliiv.  Bdd.  6  and  10;  Finkler,  ibid  ,  Bdd,  10  and  U ; 
Oertman,  ibid.,  Bdd.  14  and  15;  Hoppe-Seyler,  ibid.,  Bd.  7. 


4  INTRODUCTION. 

The  cause  of  the  animal  oxidation  is  considered,  by  Pflugek 
and  several  other  investigators,  to  he  dependent  upon  the  special 
contitution  of  the  protoplasmic  proteids.  This  investigator  calls- 
the  proteids  outside  of  the  organism,  and  also  those  which  circulate 
in  the  blood  and  fluids,  "  non-living  proteids  "  as  compared  to  those 
which  are  converted  by  the  activity  of  the  living  cell  into  living 
protoplasm,  which  he  calls  "  living  proteids,"  It  is  now  also  con- 
sidered that  this  "living  proteid  "  differs  from  the  "non-living 
proteid  "  by  a  greater  mobility  of  the  atoms  within  the  molecule, 
and  it  may  be  characterized  by  a  greater  inclination  towards  intra- 
molecular changes  of  position  of  these  atoms. 

The  reason  for  these  greater  intramolecular  movements  Pfluger  * 
ascribes  to  the  presence  of  cyanogen,  Loew  ^  to  the  presence  of 
aldehydic  groups,  and  Latham  ^  attributes  it  to  the  presence  of  a 
chain  of  cyanalcohols  in  the  proteid  molecule. 

Pfluger  considers  these  differences  between  ordinary  proteids 
and  living  protoplasmic  proteids  as  the  cause  for  the  oxidation 
processes  in  the  animal  organism.  These  processes  show  certain 
similarity  to  the  oxidation  of  phosphorus  in  an  atmosphere  contain- 
ing oxygen.  In  this  process  the  phosphorus  is  not  only  itself 
oxidized,  but,  as  it  splits  the  oxygen  molecules  and  sets  free  oxygen 
atoms  (active  oxygen),  it  may  cause  at  the  same  time  an  indirect  or 
secondary  oxidizing  action  upon  other  bodies  present.  In  an 
analogous  way  the  living  protoplasmic  proteid,  which  is  not,  like 
dead  proteid,  indifferent  to  molecular  oxygen,  may  cause  a  splitting 
of  the  oxygen  molecule,  thus  becoming  itself  oxidized,  and  at  the 
same  time  setting  oxygen  atoms  free,  which  may  cause  a  secondary 
oxidation  of  other  less  oxidizable  substances. 

Active  oxygen  may  also  be  produced,  according  to  0.  Nasse," 
by  a  hydroxylization  of  the  constituents  of  the  protoplasm  with  the 
splitting  off  of  molecules  of  water.  If  benzaldehyde  is  shaken  with 
water  and  air  an  oxidation  of  the  benzaldehyde  into  benzoic  acid 
takes  place,  while  oxidizable  substances  present  at  the  same  time 
may  also  be  oxidized.  The  simultaneous  presence  of  potassium 
iodide  and  starch  or  tincture  of  guaiacum  causes  a  blue  coloration 
because  the  hydroxy  1  (OH)  takes  the  place  of  the  hydrogen  in  the 

'  Pfiuger's  Arcliiv,  Bd.  10. 

'^Loevv  and  Bokorny,  Pfliiger's  Archiv,  Bd.  25,  and  Loew,  ihiiL,  Bd.  30. 

3  British  Medical  Journal,  1886. 

4  Rostocker  Zeitung,  1891,  No.  534. 


ANIMAL   OXIDATIONS.  5 

aldehyde  group  and  these  two  hydrogen  atoms,  one  derived  from 
the  aldehyde  and  the  other  from  the  splitting  of  the  water,  have 
a  splitting  action  on  the  molecular  oxygen.  ISTasse  and  Rosixg  ' 
have  found  that  certain  varieties  of  proteid  have  the  property  of' 
being  hydroxylized  in  the  presence  of  water,  and  a  series  of  oxida- 
tions in  the  animal  body  may,  according  to  Nasse,  be  accounted 
for  by  the  oxygen  atoms  set  free  in  the  hydroxylization  similar  to 
that  of  benzaldehyde. 

Another  very  widely  diffused  view  exists  in  regard  to  the  origin 
■of  the  activity  of  the  oxygen,  namely,  that  by  the  decomposition 
processes  in  the  tissues  reducing  substances  are  formed  which  split 
the  oxygen  molecule,  uniting  with  one  oxygen  atom  and  setting  the 
other  free. 

The  formation  of  reducing  substances  during  fermentation  and 
putrefaction  is  generally  known.  The  butyric  fermentation  of 
dextrose  in  which  hydrogen  is  set  free — CgH,,Og  =  C^H^O,  +  200, 
+  2(HJ — is  an  example  of  this  kind.  Another  example  is  the 
appearance  of  nitrates  in  consequence  of  an  oxidation  of  nitrogen  in 
cases  of  putrefaction,  which  process  is  ordinarily  explained  by  the 
statement  that,  in  putrefaction,  reducing,  easily  oxidizable  bodies 
are  formed  which  split  oxygen  molecules,  liberating  oxygen  atoms 
which  afterward  oxidize  the  nitrogen,  li,  is  assumed  also  that  the 
cells  of  the  animal  tissues  and  organs  have  the  property  like  these 
lower  organisms,  which  cause  fermentation  and  putrefaction,  of 
•causing  splitting  processes  in  which  easily  oxidizable  substances 
perhaps  also  hydrogen  in  statu  nasce?idi  (Hoppe-Setler''),  are 
produced.  The  observations  of  Ehrlich,'  that  certain  blue  color- 
ing matters — alizarin  blue  and  indophenol  blue — are  decolorized  by 
ihe  tissues  of  the  living  animal  and  become  blue  again  on  exposure 
to  air,  seem  also  to  be  a  proof  of  the  occurrence  of  easily  oxidizable 
combinations  in  the  tissues.  A  further  proof  of  this  is  found  in 
the  observations  of  C.  Ludwig  and  Alex.  Schmidt  '  that  in  the 
blood  of  asphyxiated  animals,  as  well  as  in  the  absence  of  oxygen, 
an  accumulation  of  reducing,  easily  oxidizable  substances  takes 
place. 

'Ernst  Ros.iig,  Untersuchungen  ilber  die  Oxydation  von  Eiweiss  in  Gegen- 
wart  von  Scliwefel.     Inaug.  Dissert.     Rostock,  1881. 
2  Pflllger's  Archiv.  Bd    12. 

^P.  Ehrlicb,  Das  SauerstofEbedurfniss  des  Organismus      Berlin,  1885. 
*  Arbeiten.aus  der  pbysiol.  An^talt  zu  Leipzig.     1867. 


6  INTRODUCTION. 

In  accordance  with  what  has  been  stated  above,  we  may  assume 
that  the  oxidation  in  the  animal  body  takes  place  in  the  following^ 
manner:  The  forces  peculiar  to  protoplasm,  unknown  to  us,  but 
acting  similarly  to  heat  or  the  enzymes,  cause  a  splitting,  producing 
reducible  and  readily  oxidizable  products  on  one  side  and  difficultly 
oxidizable  products  on  the  other.  The  first  may  be  directly  oxi- 
dized, and  as  they  cause  a  splitting  of  the  molecular  oxygen,  setting 
active  oxygen  free,  they  may  also  be  the  indirect  cause  of  the  oxi- 
dation of  the  more  difficultly  oxidizable  substances,  namely  cause- 
ing  a  SECONDAKT  OXIDATION"/  The  products  formed  by  these 
splittings  and  oxidations  may  perhaps  in  part  be  burned  within 
the  body  without  undergoing  further  splitting,  but  they  must  prob- 
ably first  undergo  a  further  splitting  and  then  succumb  to  consecu- 
tive oxidation,  until  after  repeated  splitting  and  oxidation  the  final 
products  of  metabolism  are  formed. 

The  oxidations  in  the  animal  body  have  long  been  designated  as 
a  combustion,  and  such  a  view  is  easily  reconcilable  with  the  above- 
mentioned  views.  In  combustion  in  the  ordinary  sense,  as,  for 
'example,  the  burning  of  wood  or  oil,  we  must  not  forget  that  the 
substances  themselves  do  not  combine  with  oxygen.  It  is  only 
after  the  action  of  heat  has  decomposed  these  bodies  to  a  certain 
degree  that  the  oxidation  ot  the  products  of  such  decomposition 
'takes  place  and  is  accompanied  by  the  phenomenon  of  light. 
'.  The  numerous  intermediary  products  of  decomposition  which 
,we  observe  in  the  animal  body  teach  us  that  the  oxidations  and 
splittings  of  the  components  of  the  body  do  not  take  place  at  once 
and  suddenly,  but  only  very  gradually,  step  by  step,  until  the  final 
products  of  exchange  are  reached. 

A  very  instructive  example  of  such  a  gradual  decomposition 
outside  of  the  organism  has  been  shown  by  Drechsel''  in  his  inves- 
tigation on  the  electrolysis  of  phenol  by  an  alternating  current. 
By  experiments  with  alternating  electric  currents  we  obtain,  of 
course,  in  the  watery  solution  of  the  substance,  at  each  electrode 
alternately,  oxygen  and  hydrogen  in  great  rapidity.  Therefore 
oxidations  and  reductions  must  take  place  alternately,  and  we 
obtain  syntheses  as  well  as  splittings  with  oxidations. 

If  phenol  in  watery  solution  is  exposed  to  such  an  alternating 

'0.  Nasse,  Pfiliger's  Archiv,  Bd.  41. 

■^Journal  f.  prakt.  Cbemie  (N.  F.),  Bd.  22,  29,  38;  also  Festschrift  f.  C. 
Ludwig,  1887. 


ANIMAL   OXIDATIONS.  7 

current,  we  produce,  by  the  combined  action  of  reduction  and  oxi- 
dation processes,  a  new  body — hydro-phenoketon,  0^11,^0 — by  aggre- 
gation of  hydrogen  atoms  with  the  simultaneous  rupture  of  all 
double  bonds  of  the  benzol  ring  and  then  an  oxidation  with  the 

CH, 

removal  of  hydrogen  atoms  or  T^''r^\       |/^itt  •     From  the  hydro- 


phenoketon  a  compound  of  the  fatty  series  is  produced  by  the 
fixation  of  0  +  2H  accompanied  with  the  splitting  of  the  benzol 

1  1  •         VI     mr   n  HC/^COOH 

rmg,  namely,  normal  caproic  acid.  (J,H,jO,,  or  itV<|       Ir-jr 

By  further  electrolysis  of  the  caproic  acid,  with  the  removal  of 
carbon  as  carbon  dioxide  and  of  hydrogen  as  water,  a  series  of  acids 
with  decreasing  amounts  of  carbon  are  obtained,  and  in  this  way  we 
may,  by  properly  directed  combination  of  reductions  and  oxidations, 
pass  from  a  body  of  the  aromatic  series  to  a  body  of  the  fatty  series, 
and  then  to  substances  in  which  the  amount  of  carbon  decreases, 
until  the  final  metabolic  products  are  reached. 

As  Dkechsel  has  also  found  that  the  same  electro-syntheses  (of 
urea  and  phenol-sulphuric  acid)  are  produced  by  the  continuous 
as  with  the  alternating  current,  and  since  the  occurrence  of  gal- 
vanic currents  in  the  body  has  been  positively  shown,  Drechsei> 
concludes  that  not  only  do  syntheses,  but  also  the  combustion  of 
foods  and  constituents  of  the  tissues,  take  place  in  the  animal  body 
in  consequence  of  a  quick  succession  of  reductions  and  oxidations 
produced  in  this  way. 

Most  investigators  are  without  doubt  agreed  in  the  view  that  a 
united  action  of  oxidation  and  reduction  processes  takes  i^lace  in 
the  animal  body.  The  views  in  regard  to  tlie  kind  and  origin  of 
this  co-operative  action  are  divided.' 

In  the  previous  pages  we  have  spoken  of  the  formation  of  active 
oxygen,  but  there  are  also  investigators  who  do  not  assent  to  such 
a  theory,  or  at  least  not  entirely.     Traube''  has  brought  forward 

■  M.  Nencki,   Arch,   des  sciences  blol.   de  I'lnstitut  imperial   de  Medecine 
exper.  a  bt.  Petersbourg.     Tome  1,  No.  4,  p.  483. 

'  Ber.  d.  deutscb.  cbem.  Gesellsch.,  Bdd.  15,  18,  19,  and  26. 


8  INTRODUCTION. 

powerf q1  arguments  against  the  view  that  the  so-called  slow  com- 
bustion or  sj^ontaneous  oxidation  causes  a  splitting  of  the  oxygen 
molecule.  He  has  shown  that  this  theory  does  not  account  for 
many  cases  of  auto-oxidation.  Traube  '  for  a  long  time  has  ex- 
plained the  oxidations  in  the  animal  organism  by  the  statement 
that  within  the  organism  so-called  oxygen-carriers  occur  which  act 
similarly  to  nitric  oxide  in  the  sulphuric-acid  manufacture,  where 
oxidation  is  the  result  of  the  absorption  and  liberation  of  oxygen  by 
other  substances  which  are  themselves  not  directly  oxidized  by 
molecular  oxygen. 

De  Ket-Pailhade  ^  has  been  able  to  isolate  such  a  body  from 
yeast  and  animal  tissues.  He  calls  the  body  ^j/iiVo^/u'ow,  and  it  has 
the  property  of  developing  sulphuretted  hydrogen  from  finely 
divided  sulphur.  This  substance,  which  seems  to  be  a  combination 
«f  hydrogen  with  a  hypothetical  radicle,  can  take  up  oxygen  and 
form  water.  The  radicle  set  free  takes  up  hydrogen  from  water  by 
splitting,  setting  free  oxygen,  which  acts  upon  other  bodies,  oxidiz- 
ing them.  The  regenerated  philothion  takes  up  oxygen  again,  and 
.so  the  processes  go  on.  Nasse  and  Rosing  '  explain  the  observa- 
tions of  De  Rey-Pailhade  in  another  way. 

The  observation  first  made  by  Jaquet  *  and  then  positively 
-confirmed  by  Salkowski,'  Spitzer,"  Abelous,  and  Biarnes  '  that 
a  body  similar  to  a  ferment  occurs  in  various  tissues  and  also  in  the 
blood,  which  has  the  property  of  oxidizing  certain  bodies  such  as 
benzalcohol,  salicylic  aldehyde,  and  dextrose.  Nothing  positive  can 
be  given  at  the  present  time  as  to  the  importance  of  this  oxidation 
ferment  in  the  oxidation  in  the  animal  body. 

RoHMANN  *  and  Spitzer  °  have  shown  that  there  exist  oxida- 
tion ferments  in  the  cells  and  tissues  of  the  body  which  act  as 
oxygen-carriers  in  Traube's  sense.  These  bodies,  whose  activity 
is  destroyed  by  heat,  not  only  have  an  action  on  hydrogen  peroxide 

'  Traube,  Theorie  der  Fermentwirkungen.     Berlin,  1858. 

'  Recherches  exper.  sur  le  Philothion,  etc.  Paris,  1891,  and  Nouvelles 
rechi-rches  sur  le  Philothion.     Paris,  1892. 

'  Unters.  iiber  die  Oxydation  von  Eiweiss  in  Gegenwart  von  Schwefel. 
Inaug.  Dissert.     Rostock,  1891. 

4  Arch.  f.  expt.  Path.  u.  Pliarm.,  Bd.  29. 

*Centralbl.  f.  d.  med.  Wissensch.,  1893  and  1894. 

•Berlin,  klin.  Wochenschr. ,  1894. 

'  Arch,  de  Physiol.  (.^),  Tome  6. 

*Ber.  d.  deutsch.  cheiu.  ueseilsch.,  Bd.  28. 

•Pfluger's  Arch.,  Bd.  60. 


SPLITTING  PROCESSES.  9 

bat  also  on  neutral  oxygen,  which  the  authors  have  shown  by 
special  pigment  syntheses.  Thus  the  syntheses  of  indophenol  from 
a-naphthol  and  paraphenylendiamin  only  take  place  gradually  in 
the  air  in  the  presence  of  alkali,  whilst  a  very  small  quantity  of  fresh 
organ  pulp  causes  an  action  in  a  few  minutes.  The  oxidation  of 
the  dextrose  in  the  blood,  the  so-called  glycolysis,  is  also  produced 
by  oxygen-carriers.  The  authors  are  therefore  not  of  the  opinion 
that  all  oxidations  of  difficultly  combustible  bodies  in  the  organism 
are  caused  by  the  oxygen-carriers.  The  oxygen-carriers  are  not 
identical  with  the  auto-oxidizable  bodies;  not  those  as  considered 
by  Hoppe-Setler  as  the  cause  of  oxidation,  but  those  which  always 
act  reducing. 

An  important  source  of  the  living  energy  developed  in  the  body 
is  to  be  sought  for  in  the  oxidation  effected  by  oxygen  of  strong 
potential  energy,  but  splitting  processes  are  also  important.  In 
these  complicated  chemical  compounds  are  reduced  to  simpler  ones, 
and  therefore  the  atoms  change  from  a  mobile  equilibrium  to  a 
stabler  one  and  stronger  chemical  affinities  are  satisfied,  converting 
chemical  potential  energy  into  living  energy  {vis  viva).  The  best- 
known  example  of  such  a  splitting  process  outside  of  the  animal 
organism  is  the  ordinary  alcoholic  fermentation  of  dextrose, 
CgHjjO,  =  2C0,  -|-  2C,H,0,  in  which  process  heat  is  set  free. 
The  animal  body  may  also  have  a  source  of  energy  in  the  splitting 
processes  which  are  not  dependent  on  the  presence  of  free  oxygen. 
The  processes  taking  place  in  the  living  muscle  yield  an  example 
of  this  kind.  A  removed  muscle,  which  gives  no  oxygen  when  in 
a  vacuum,  may,  as  Hermaxn  '  has  shown,  work,  at  least  for  a 
time,  in  an  atmosphere  devoid  of  oxygen,  and  give  off  carbon 
dioxide  at  the  same  time. 

We  call  processes  of  splitting  which  are  accompanied  by  a 
decomposition  of  water  and  then  a  taking  up  of  its  constituents 
hydrolytic  splittings.  These  splittings,  which  play  an  important 
role  within  the  animal  body,  and  which  are  most  frequently  met 
with  in  the  process  of  digestion,  are,  for  example,  the  transforma- 
tion of  starch  into  dextrose  and  the  splitting  of  neutral  fats  into  the 
corresponding  fatty  acid  and  glycerin : 

C3H,(C,,H3,0J3  +  3H,0  =  C,H,(0H)3  +  3(C.,H„0,). 

Tristearin.  Glycerin.  Stearic  acid. 

'  Untersucliungen  liber  den  StofEweclisel  der  Muskeln.     Berlin,  1867. 


10  INTRODUCTION. 

As  a  rule  the  hydrolytic  splitting  processes  as  they  occur  in  the 
animal  body  may  be  performed  outside  of  it  by  means  of  higher 
temperatures  with  or  without  the  simultaneous  action  of  acids  or 
alkalies.  Considering  the  two  above-mentioned  examples,  we  know 
that  starch  is  converted  into  dextrose  when  it  is  boiled  with  dilute 
acids,  and  also  that  the  fats  are  split  into  fatty  acids  and  glycerin 
on  heating  them  with  caustic  alkalies  or  by  the  action  of  super- 
heated steam.  The  heat  or  the  chemical  reagents  which  are  used 
for  the  performance  of  these  reactions  would  cause  immediate  death 
if  applied  to  the  living  system.  Consequently  the  animal  organism 
must  have  other  means  at  its  disposal  which  act  similarly,  bat  in 
such  a  manner  that  they  may  work  without  endangering  the  life  or 
normal  constitution  of  the  tissues.  Such  means  have  been  recog- 
nized in  the  so-called  unorganized  ferments  or  enzymes. 

Alcoholic  fermentation,  as  well  as  other  processes  of  fermenta- 
tion and  putrefaction,  is  dependent  upon  the  presence  of  living 
organisms,  ferment  fungi  and  splitting  fungi  of  different  kinds. 
The  ordinary  view,  according  to  the  researches  of  Pasteur,  is 
that  these  processes  are  to  be  considered  as  phases  of  life  of  these 
organisms.  The  name  organized  ferments  or  ferments  has  been 
given  to  such  micro-organisms  of  which  ordinary  yeast  is  an  exam- 
ple. However,  the  same  name  has  also  been  given  to  certain  bodies 
or  mixtures  of  bodies  of  unknown  organic  origin  which  are  products 
of  the  chemical  work  within  the  cell,  and  which,  after  they  are 
separated  from  the  cell,  are  capable  in  the  smallest  quantities  of 
causing  a  decomposition  or  splitting  in  very  considerable  quantities 
of  other  substances  without  entering  into  combination  with  the 
decomposed  body  or  with  any  of  its  products  of  splitting  or  decom- 
position. Such  ferments  are,  for  example,  the  diastase  of  malt  and 
the  ferments  secreted  by  the  different  glands  participating  in  the 
process  of  digestion.  These  formless  or  unorganized  ferments  are 
generally  called,  according  to  Kuhjste,  enzymes. 

A  ferment  in  a  more  restricted  sense  is  therefore  a  living  being, 
while  an  enzyme  is  a  product  of  chemical  processes  in  the  cell,  a 
product  which  has  an  individuality  even  without  the  cell,  and 
which  may  be  active  when  separated  from  the  cell.  The  splitting 
of  invert-sugar  into  carbon  dioxide  and  alcohol  by  fermentation  is 
a  fermentative  process  closely  connected  with  the  life  of  the  yeast. 
The  inversion  of  cane-sugar  is,  on  the  contrary,  an  enzymotic 
process  caused  by  one  of  the  bodies  or  mixture  of  bodies  formed  by 


FERMENTS  AND  ENZYMES.  11 

the  living  ferment,  which  can  be  severed  from  this  ferment,  and 
still  remains  active  even  after  the  death  of  the  latter.  Consequently 
ferments  and  enzymes  are  capable  of  manifesting  a  different 
behavior  towards  certain  chemical  reagents.  Thus  there  exist  a 
number  of  substances,  among  which  we  may  mention  arsenious 
acid,  phenol,  salicylic  acid,  boracic  acid,  chloroform,  ether,  and 
others,  which  in  certain  concentration  kill  ferments,  but  which  do 
not  noticeably  impair  the  action  of  the  enzymes.  A  very  service- 
able substance  in  this  regard  is,  according  to  the  investigations  of 
Arthus  and  Huber,'  a  Ifo  solution  of  sodium  fluoride. 

The  enzymes  may  as  above  stated  act  when  separated  from  the 
cell,  and  are  thus  extracellular,  but  this  does  not  preclude  the  pos- 
sibility that  we  also  may  liave  enzymes  which  develop  their  action 
within  the  cell  and  therefore  are  intracellular.  As  an  example  of 
such  an  enzyme  we  may  mention  the  enzyme  existing  in  the 
micrococcus  urea?  which  has  the  power  of  decomposing  urea,  and 
also  another  enzyme,  produced  by  a  bacterium,  which  decomposes 
calcium  formate  into  calcium  carbonate  and  hydrogen. 

It  is  doubtful,  indeed  highly  improbable,  whether  it  has  been 
possible  up  to  the  present  time  to  isolate  any  enzyme  in  a  pure 
state.  Therefore  the  nature  of  the  enzymes  and  their  elementary 
composition  are  unknown.  Such  as  have  been  obtained  thus  far 
appear  to  be  nitrogenized  and  to  be  similar  in  some  degree  to 
proteid  bodies.  The  enzymes  are  considered  as  proteid  bodies  by 
many  investigators,  but  this  opinion  has  not  sufficient  foundation. 
It  is  indeed  true  that  the  enzymes  isolated  by  certain  investigators 
act  like  genuine  proteid  bodies;  but  it  is  undecided  whether  or  not 
the  products  isolated  in  these  instances  were  pure  enzymes  or  were 
composed  of  enzymes  contaminated  with  proteids. 

The  enzymes  may  be  extracted  from  the  tissues  by  means  of 
water  or  glycerin,  especially  by  the  latter,  which  forms  very  stable 
solutions  and  consequently  serves  as  a  means  of  extracting  them. 
The  enzymes,  generally  speaking,  do  not  appear  to  be  diffusible. 
They  are  readily  carried  down  with  other  substances  when  these 
precipitate  in  a  finely  divided  state,  and  this  property  is  extensively 
taken  advantage  of  in  the  preparation  of  pure  enzymes.' 

The  property   of    many   enzymes   of    decomposing   hydrogen 


'  Archives  de  Physiologie,  1892.     (5)  Tome  4, 
'Briicke,  Wiener  Sitzungsbericht,  Bd.  43.     1861. 


12  INTRODUCTION. 

peroxide  is,  according  to  Alex.  Schmidt,"  not  dependent  upon 
the  enzyme,  bat  is  caused  by  the  contamination  of  the  enzyme  with 
constituents  from  the  protoplasm.  Tliis  coincides  witli  the  obser- 
vations of  Jacobsok  ^  on  emulsin,  pancreas  enzyme,  and  diastase 
that  the  catalytic  property  may  be  destroyed  by  proper  means  with- 
out diminishing  the  specific  enzymotic  action.  The  continued 
heating  of  their  solutions  above  +  80°  C.  generally  destroys  most 
of  the  enzymes.  In  the  dry  state,  however,  certain  enzymes  may 
be  heated  to  100°  or  indeed  to  150°-160°  C.  without  losing  their 
power.  The  enzymes  are  precipitated  from  their  solutions  by 
alcohol. 

We  have  no  characteristic  reactions  for  the  enzymes  in  general, 
and  each  enzyme  is  characterized  by  its  specific  action  and  by  the 
conditions  under  which  it  operates.  Bat  it  mast  be  stated  that, 
however  the  different  enzymes  may  vary  in  action,  they  all  seem  to 
have  this  in  common,  that  by  their  presence  an  impulse  is  given  to 
split  more  complicated  combinations  into  simpler  ones,  whereby  the 
atoms  arrange  themselves  from  an  unstable  eqailibrium  into  a  more 
stable  one,  chemical  tension  is  transformed  into  living  force,  and 
new  products  are  formed  with  lower  heat  of  combastion  than  the 
original  substance.  The  presence  of  water  seems  to  be  a  necessary 
factor  in  the  perfection  of  such  decompositions,  and  the  chemical 
process  seems  to  consist  in  the  taking  up  of  the  elements  of  water. 

The  action  of  the  enzymes  may  be  markedly  inflaenced  by 
external  conditions.  The  reaction  of  the  liqaid  is  of  special  im- 
portance. Certain  enzymes  act  only  in  acid,  others,  and  the 
majority,  on  the  contrary  act  only  in  neatral  or  alkaline  liquids. 
Certain  of  them  act  in  very  faintly  acid  as  well  as  in  neutral  or 
alkaline  solutions,  but  best  at  a  specific  reaction.  The  temperature 
exercises  also  a  very  important  influence.  In  general  the  activity 
of  enzymes  increases  to  a  certain  limit  with  the  temperature.  This 
limit  is  not  always  the  same,  but  is  dependent  upon  the  quantity 
of  enzyme.'  The  products  of  the  enzymotic  processes  exercise  a 
retarding  influence.  Additions  of  various  kinds  may  have  a  re- 
tarding and  others  an  accelerating  action. 

Fermi  and  Pernossi  *  have  studied  the  action  of  various  influ- 

'  Al.  Schmidt,  Ziir  Blutlehre.     Leipzig,  1892. 
«Zeitschr   f.  pbysiol.  Chemie,  Bd.  16,  S.  340. 
»Tammann,  Zeitscbr.  f.  pb3'siol.  Cbem.,  Bd.  16,  S.  271. 
<Zeitschr.  f.  Hygiene,  Bd.  18. 


ENZYMES  AND   PTOMAINES.  13 

eiices  on  the  enzymes.  Starting  with  the  assumption  that  when 
the  free  ions  are  set  free  by  the  action  of  enzymes  the  electrical 
conductivity  of  the  water  must  be  raised,  0.  IS^asse  '  experimented 
with  soluble  starch,  partly  boiled  and  partly  unboiled,  and  diastase, 
and  determined  the  resistance  according  to  Kohlrausch's  method 
and  observed  a  considerable  increase  in  the  conductivity  of  the 
active  diastase  solutions. 

The  animal  enzymes  are  divided  into  several  groups.  The  most 
studied  of  these  are  the  hydrolytic  enzymes  found  in  the  digestive 
canal.  The  three  most  important  groups  are  the  amylolytic  or 
diastatic,  the  proteolytic  or  those  converting  proteids  into  soluble 
modifications,  and  the  steatolytic  or  fat-splitting  enzymes.  The 
coagulating  enzymes  form  a  peculiar  group.  The  mode  of  action 
of  these  enzymes,  amongst  which  we  reckon  chymosin  (rennin)  or 
casein-coagulating,  and  fibrin  ferment  or  blood-coagulating,  is  still 
less  known  than  the  others.  The  manner  in  which  these  enzymes 
work  is  still  obscure,  but  their  action  may  be  considered,  in 
several  respects,  as  very  closely  related  to  the  so-called  catalytic  or 
contact  action. 

As  above  stated,  the  enzymes  are  of  great  imj^ortance  for  the 
chemical  processes  going  on  in  the  digestive  tract,  bat  we  have  to 
add  that  the  results  of  their  action  are  greatly  complicated  by 
processes  of  putrefaction  which  take  place  in  the  intestine  at  the 
same  time,  and  which  are  caused  by  micro-organisms.  Micro- 
organisms therefore  exercise  a  certain  influence  on  the  physiological 
processes  of  the  animal  body.  These  organisms,  when  they  enter 
the  animal  fluids  and  tissues  and  develop  and  increase,  are  of  the 
greatest  pathological  importance,  and  modern  bacteriology  in  rela- 
tion to  the  doctrine  of  infectious  diseases,  founded  by  Pasteur  and 
Koch,  gives  efficient  testimony  to  these  facts. 

Putrefaction  caused  within  the  animal  fluids  and  tissues  by 
lower  organisms  may  produce,  among  others,  combinations  of  a 
basic  nature.  Such  bodies  were  first  found  by  Selmi  in  human 
cadavers,  and  called  by  him  cadaver  alkaloids  or  ptomaines.  These 
ptomaines,  which  have  been  isolated  from  cadavers  and  some  from 
putrefying  proteid  mixtures,  have  been  closely  studied  by  Selmi," 

•  Rostocker  Zeitung,  1894. 

'  Sulle  ptomaiue  od  alcaloidi  cadaverici  e  loro  importanza  in  tossicologia. 
Bologna,  1878.     Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  11. 


14  INTRODUCTION. 

Beiegee,'  and  G^autier,"  and  are  considered  as  products  of  chem- 
ical processes  caused  by  putrefaction  microbes.  The  first  ptomaine 
to  be  analyzed  was  coUidin,  Cj^H^.N,  obtained  by  Nencki/  on  the 
putrefaction  of  gelatin.  Since  then  many  ptomaines  have  been 
anlayzed  by  Gautier,  and  especially  by  Briegee.  Certain  of  the 
ptomaines  originate  undoubtedly  from  lecithin  and  other  so-called 
extractives  of  the  tissues,  but  the  majority  seem  to  be  derived  from 
the  protein  substances  by  decomposition. 

Some  ptomaines,  although  all  belong  to  the  aliphatic  series, 
contain  oxygen  and  others  are  free  from  oxygen.  The  majority  of 
the  true  ptomaines  belong  to  the  latter  group.  Most  of  the 
ptomaines  isolated  by  Briegee  are  diamines  or  compounds  derived 
from  the  same.  Amongst  the  diamines  we  have  two,  cadaverin  or 
pentamethylendiamin,  C^H^^N,,  and  putrescin  or  tetramethylendi- 
amin,  C^H,^^^,  which  are  of  special  interest  because  they  have  been 
found  in  the  intestinal  tract  and  urine  in  certain  pathological  con- 
ditions, namely,  cholera'  and  cystinuria."  Some  of  the  ptomaines 
are  exceedingly  poisonous,  while  others  are  not.  The  poisonous 
ones  are  called  toxines,  according  to  the  suggestion  of  Briegee. 

The  formation  of  such  toxines  in  the  decompositions  caused  by 
putrefactive  microbes  makes  it  probable  that  the  lower  organisms 
acting  in  infectious  diseases  also  produce  poisonous  substances 
which  may  cause  by  their  action  the  symptoms  or  complications  of 
the  disease.  Briegee,  who  has  become  prominent  by  his  study 
of  this  subject,  has  been  able  to  isolate  from  typhus  cultures  a  sub- 
stance called  typliotoxin  which  has  a  poisonous  action  on  animals; 
and  he  has  also  prepared  another  substance,  tetanvii,"  from  the 
amputated  arm  of  a  patient  with  tetanus,  animals  inoculated  with 
which  die  exhibiting  symptoms  of  developed  tetanus. 

As  above  stated,  the  chemical  processes  in  animals  and  plants 
do  not  stand  in  opposition  to  each  other;  they  offer  differences 

'Ueber  Ptomaine,  Parts  1,  2,  and  3.     Berlin,  1885-1886. 

'Traite  de  cbimie  appliquee  a  ia  physiologic,  Tome  2,  1873.  Compt. 
rend  us.  Tome  94. 

5  Ueber  die  Zersetzung  der  Gelatine,  etc.     Bern,  1876. 

^Brieger,  Berlin,  klin.  Wocbenschr.,  1887. 

'Baumann  and  Udransky,  Zeitschr.  f.  pbysiol.  Chem.,  Bdd.  13  and  15; 
Brieger  and  Stadthagen,  Berlin,  klin .  Wocbenschr  .  1889. 

«Brieger.  Arch.  f.  patboi.  Anat.,  Bdd.  112  and  115.  Also  Sitzungsber.  d. 
Berl.  Akad.  d.  W.,  1889.  and  Berl.  klin.  Wocbenschr.,  1888, 


LEUCOMAINEti.  15 

indeed,  but  still  they  are  of  the  same  kind  from  a  qnalitative  stand- 
point. 

Pfluger  says  that  there  exists  a  blood-relationship  between  all 
living  cells  of  the  animal  and  vegetable  kingdoms,  and  that  they 
originate  from  the  same  root;  and  if  the  organisms  consisting  of 
one  cell  can  decompose  protein  substances  in  such  a  manner  as  to 
produce  poisonous  substances,  why  should  not  the  animal  body, 
which  is  only  a  collection  of  cells,  be  able  to  produce  under 
physiological  conditions  similar  poisonous  substances  ?  It  has  been 
known  for  a  long  time  that  the  animal  body  possesses  this  ability 
to  a  great  extent,  and  as  well-known  evidence  of  this  ability  we  may 
mention  various  nitrogenized  extractives  and  poisonous  constituents 
of  the  secretions  of  certain  animals.  Those  substances  of  basic 
nature  which  are  incessantly  and  regularly  produced  as  products  of 
the  decomposition  of  the  protein  substances  in  the  living  organism, 
and  which  therefore  are  to  be  considered  as  products  of  the  physi- 
ological exchange  of  material,  have  been  called  leucomaines  by 
Gautier  '  in  contradistinction  to  the  ptomaines  and  toxines  pro- 
duced by  micro-organisms.  These  bodies,  to  which  belong  several 
well-known  animal  extractives,  were  isolated  by  Gautier  from 
animal  tissues  such  as  the  muscles.  The  hitherto  known  leuco- 
maines, of  which  a  few  are  poisonous  in  small  amounts,  belong  to 
the  cholin,  the  uric  acid,  and  the  creatinin  group. 

The  leucomaines  are  considered  as  being  of  certain  importance 
as  causes  of  disease.  It  has  been  contended  that  when  these  bodies 
accumulate  on  account  of  an  incomplete  excretion  or  oxidation  in 
the  system,  an  auto-intoxication  may  be  produced  (Bouchard  '^). 

The  toxines  and  the  poisonous  leucomaines  are,  however, 
neither  the  only  nor  the  most  active  poison  produced  by  the  plant 
or  animal  cell.  Later  investigations  have  shown  that  certain  plants 
as  well  as  animals  can  produce  proteids  which  are  exceedingly 
poisonous.  Such  poisonous  proteids  have,  for  example,  been 
isolated  from  the  jequirity  and  castor  beans,  as  also  from  tbe  venom 
of  snakes,  spiders,  and  other  animals.  The  toxic  proteids  produced 
by  pathogenic  micro-organisms  are  of  special  interest.  Proteids 
have  been  isolated  from  the  cultures  of  various  pathogenic  microbes 

'Bull.  soc.  chim.,  43,  and  A..  Gautier,  Sur  les  alcaloides  derives  de  la  de- 
struction bacterienne  ou  physiologique  des  tissus  animaux.     Paris,  1886. 

*  Bouchard,  Le9ons  sur  les  auto-intoxications  dans  les  maladies.    Paris,  1887. 


Id  INTRODUCTION. 

within  the  last  few  years  (Brieger  and  Frankel  ')  which  are 
exceedingly  poisonous,  and  which  reproduce  the  sj^mptoms  of  the 
infection  more  exactly  than  the  toxine.  These  proteids  have  been 
called  toxalbumms  by  Brieger  and  Frankel. 

It  is  of  great  interest  that  we  know  also  of  proteid  bodies  some 
of  which,  like  the  so-called  alexmes  in  the  blood  serum,  have  a 
germicidal,  or  bactericidal  action,  while  others  make  the  animal 
body  immune  against  infection  with  a  certain  microbe  or  protect 
the  body  against  the  poison  produced  by  the  microbe.  The  great 
importance  of  these  observations  is  apparent,  but  as  it  is  not  within 
the  range  of  this  book  we  will  not  further  discuss  the  subject. 
The  nature  of  these  remarkable  proteids  will  be  given  somewhat  in 
detail  in  the  following  chapter. 

'  Berl.  klin.  Wochenschr.,  1890. 


CHAPTEE   11. 

THE   PROTEIN   SUBSTANCES. 

The  chief  mass  of  the  organic  constituents  of  animal  tissues 
consists  of  amorphous,  nitrogenized,  very  complex  bodies  of  high 
molecular  weight.  These  bodies,  which  are  either  proteids  in  a 
special  sense  or  bodies  nearly  related  thereto,  take  first  rank  among 
the  organic  constituents  of  the  animal  body  on  account  of  their 
great  abundance.  For  this  reason  they  are  classed  together  in  a 
special  group  which  has  received  the  name  protein  group  (from 
TTpoDxevo^  1  am  the  first,  or  take  the  first  place).  The  bodies 
belonging  to  these  several  groups  are  called  protein  suhstanceSy 
although  in  a  few  cases  the  proteid  bodies  in  a  special  sense  are 
designated  by  the  same  name. 

The  several  protein  substances  contain  carbon^  hydrogen^  ni- 
trogen^ and  oxygen.  The  majority  contain  also  sulj^hur,  a  few 
phosphorus,  and  a  few  also  'i?-on.  Copper  has  been  found  in  some 
few  cases.  On  heating  the  protein  substances  they  gradually 
decompose,  producing  inflammable  gases,  ammoniacal  compounds, 
carbon  dioxide,  water,  nitrogenized  bases,  as  well  as  many  other 
bodies,  and  at  the  same  time  they  emit  a  strong  odor  of  burnt  horn 
or  wool.  More  highly  heated  tiiey  leave  a  porous,  shining  mass  of 
carbon,  and  when  this  is  thoroughly  burnt  an  ash  is  obtained  con- 
sisting chiefly  of  calcium  and  magnesium  phosphates.  The  ques- 
tion whether  the  mineral  bodies  left  by  burning  exist  as  impurities 
or  whether  they  are  constituents  of  the  protein  molecule  has  not 
been  decided. 

It  is  at  present  impossible  to  decide  on  a  classification  of  the 
protein  substances  based  upon  their  properties,  reactions,  and  .con- 
stitution, as  well  as  ujDon  their  solubilities  and  precipitations, 
corresponding  to  the  demands  of  science.  The  best  classification 
is  perhaps  the  following  systematic  summary  of  the  better  known 

17 


18 


THE  PROTEIN  SUBSTANCES. 


and   studied   animal   protein   substances,   due   chiefly  to  Hoppe- 
Setlee  and  Drechsel.' 

I.  Simple  Proteids  or  Albuminous  Bodies. 

Seralbumin, 
Albumins \  Ovallumin, 

Lactalbumin. 

Serglohulin, 

Fibrinogen, 

Myosin, 

Musciilin, 

Crystallin, 

Vitelliiis  {?). 

Casein, 

Ovovitellin  {?),  and  others. 

Acid  albuminate. 

Alkali  albuminate. 
Albumoses  and  Peptones. 

€o       1  t  d  P    t  'd   -S  ^^^^*^' 

(  Proteids  coagulated  by  heat,  and  others. 


Globulins ....... 

Uucleo-albumins . 
Albuminates  . .  . . 


II.  Compound  Proteids. 


Haemoglobins. 
Glycoproteids 


r  Mucins  and  MucinoidSy 
\  Hyalogens, 

Ichthulin, 

Helico'proteid. 

Nucleohiston, 

Cytoglobm,  and  others. 


Nucleoproteids  . . . 

III.  Albumoids  or  Albuminoids. 


Keratin. 

Elastin. 

Collagen. 

Reticulin. 

(Amyloid.) 

(Fibroin,  Sericin,  Cornein,  Spongin,  Conchiolin,  Byssus,  and  others.) 


'See  "  Eiweisskorper, "  Ladenburg's  Handworterbucb  der  Chemie,  Bd.  3, 
S.  584-589. 


SIMPLE  PROTEIDS.  19 

To  this  summary  must  be  added  that  we  often  find  in  the 
investigations  of  animal  fluids  and  tissues  protein  substances  which 
do  not  coincide  with  the  above  scheme,  or  do  so  only  with  difficulty. 
At  the  same  time  it  must  be  remarked  that  bodies  will  be  found 
which  seem  to  rank  between  the  different  groups,  hence  it  is  very 
difficult  to  sharply  divide  these  groups. 

I.  Simple  Proteids  or  Albuminous  Bodies. 

The  simple  proteids  are  never-failing  constituents  of  the  animal 
and  vegetable  organisms.  They  are  especially  found  in  the  animal 
body,  where  they  form  the  solid  constituents  of  the  muscles, 
glands,  and  the  blood  serum,  and  they  are  so  generally  distributed 
that  there  are  only  a  few  animal  secretions  and  excretions,  such  as 
the  tears,  perspiration,  and  perhaps  urine,  in  which  they  are 
entirely  absent  or  only  occur  as  traces. 

All  albuminous  bodies  contain  carbon^  hydrogen^  nitrogen^ 
oxygen^  and  sulpliur;'  a  few  contain  also  j)lios])horus.  Iron  is 
generally  found  in  traces  in  their  ash,  and  it  seems  to  be  a  regular 
constituent  of  a  certain  group  of  the  albuminous  bodies,  namely, 
the  nucleo-albumins.  The  composition  of  the  different  albuminous 
bodies  varies  a  little,  but  the  variations  are  within  relatively  close 
limits.  For  the  better  studied  animal  proteids  the  following  com- 
position of  the  ash-free  substance  has  been  given : 

C 50.6    —  54.5  per  cent. 

H 6.5    —    7.3 

N 15.0    —  17.6 

S 0.3    —    2.2       " 

P 0.42—    0.85     " 

0 21.50  —  23.50     " 

A  part  of  the  nitrogen  of  the  proteid  molecule  is  loosely  com- 
bined and  splits  off  easily  as  ammonia  by  the  action  of  alkalies 
(Nasse'').     Sulphur  shows  the  same  property  in  nearly  all  albumi- 

'  An  exception  is  found  in  the  mycoprotein  of  putrefaction  bacteria  and  the 
anthraxprotein  of  the  anthrax  bacillus,  which  are  sulphur-free  proteids.  See 
Nencki  and  Schaffer,  Journ.  f.  prakt.  Chem.,  Bd.  20  (N.  F.),  and  Nencki,  Ber. 
d.  deutsch.  chem.  Gesellsch. ,  Bd.  17. 

"^  Pfluger's  Archiv,  Bd.  6. 


20  THE  PROTEIN  SUBSTANCES. 

nons  bodies  (Fleitmann",'  Danilewsky,'  Keuger').  A  part  of 
the  sulphur  separates  as  potassium  or  sodium  sulphide  on  boiling 
with  caustic  potash  or  soda,  and  may  be  detected  by  lead  acetate. 
What  remains  can  only  be  detected  after  fusing  with  nitre  and 
sodium  carbonate  and  testing  for  sulphates.  The  proteid  molecule 
therefore  contains  at  least  2  atoms  of  sulphur.  The  molecular 
weight  of  the  proteids  has  not  been  determined  with  accuracy  up 
to  the  present  time,  therefore  it  is  impossible  to  give  them  formulee. 
The  molecular  weight  of  ovalbumin  as  determined  by  Sabanejew 
and  Alexandrow  '  is  about  14.300.  For  the  alkali  albuminate, 
in  whose  formation  from  native  albumins  a  part  of  the  nitrogen  and 
the  loosely  bound  sulphur  is  split  off,  Lieberkuhjst  has  given  the 
formula  0,,H„,N,,SO,,. 

The  constitution  of  the  proteid  bodies,  notwithstanding  numer- 
ous investigations,  is  still  unknosvn.  By  heating  proteids  with 
barium  hydrate  and  water  in  sealed  tubes  at  150°-200°  C.  for 
several  days,  Schutzenberger  "  obtained  a  number  of  products 
among  which  were  ammonia,  carbon  dioxide,  oxalic  acid,  acetic 
acid,  and,  as  chief  product,  a  mixture  of  amido-acids.  This  mix- 
ture contained,  besides  a  little  tyrosin  and  a  few  other  bodies, 
chiefly  acids  of  the  series  C„H,„+i]SrOj  (leucines)  and  C„H,„_iNO, 
(leucemes).  The  leucines  and  leuceiues  are  formed  from  more 
complicated  substances,  with  the  general  formula  C^H.^N^O,,  by 
hydrolytic  splitting.  These  substances  are  called  glucoproteins  by 
Schutzenberger  on  account  of  their  sweet  taste.  The  sulphur  of 
the  proteids  yields  sulphites.  The  three  bodies,  carbon  dioxide, 
oxalic  acid,  and  ammonia,  are  formed  in  the  same  relative  propor- 
tion as  in  the  decomposition  of  nrea  and  oxamid;  therefore  Schut- 
zenberger suggests  that  perhaps  albumin  may  be  considered  as  a 
very  complex  ureid  or  oxamid.  Such  a  conclusion  cannot  be 
derived  from  the  above  decomposition  processes  for  several  reasons, 
and  the  attempts  to  prepare  urea  directly  by  oxidation  have  also 
given  negative  results. 

On  fusing  proteids  with  caustic  alkali,  ammonia,  mercaptan,  and 
other   volatile   products   are  generated;  also  leucin,   from   which 

'  AnnaL  der  Cbem   und  Pharm. ,  Bd.  66. 

*Zeitsclir.  f,  pbysiol.  Chem.,  Bd,  7. 

*Pliuger's  Arcliiv,  Bd.  43. 

4  See  Maly's  Jahresber.,  Bd.  21,  S.  11- 

'  Annal.  de  Chim.  et  Pbys.  (5),  16,  and  Bull.  soc.  cliim  ,  23  and  24. 


SIMPLE  PROTEIDS.  2L 

volatile  fatty  acids,  such  as  acetic  acid,  valerianic  acid,  and  also 
butyric  acid,  are  formed;  and  tyrosin,  from  which  phenol,  indol, 
and  skatol  are  produced.  On  boiling  with  mineral  acids,  or  still 
better  by  boiling  with  hydrochloric  acid  and.  tin  chloride  (Hlasi- 
WETZ  and  Habermann '),  the  proteids  yield  amido-acids,  such 
as  leucin,  aspartic  acid,  glutamic  acid,  and  tyrosin  (and  from 
vegetable  albumin  Schulze  and  Barbieri  ^  obtained  o'-phenyl- 
amidopropionic  acid),  also  sulphuretted  hydrogen,  ammonia,  and 
nitrogenized  bases  (Drechsel^).  As  an  essential  difference 
between  the  action  of  acids  and  alkalies  (barium  hydrate)  on 
albumins,  Drechsel  suggests  that  by  the  action  of  acids  carbon 
dioxide,  oxalic  and  acetic  acids  are  not  jiroduced. 

xVmongst  the  bases  obtained  by  Drechsel  from  casein  and 
by  his  pupils  E.  FrsciiER  and  ]M.  Siegfried'  from  other  proteids 
and  gelatine  on  boiling  with  hydrochloric  acid  and  tin  chloride,  we 
have  one  having  the  formula  C^Hj^NjO^  or  C^H^NjO  -|-  H^O,  which 
seems  to  be  homologous  to  creatin  or  creatinin  and  called  lysafin 
or  lysatinin  by  Drechsel.  On  boiling  lysatinin  with  bar}i:a- 
water  it  yields  urea  amongst  other  cleavage  products,  and  it  is 
therefore  possible  to  prepare  urea  artificially  from  albumin,  without 
oxidation,  by  the  hydrolysis  of  this  base.  Another  substance, 
called  lysin,  has  the  formula  CgH^^N^O^.  From  its  formula  we  find 
that  it  is  homologous  with  oniifhin,  G,li^J\^0^  (Jaffe),  which  it 
resembles  in  certain  respects  (see  Chapter  XV).  Lysin,  which  is 
probably  diamidocaproic  acid,  and  lysatinin  have  been  shown  by 
Drechsel  and  Hedix  to  be  produced  in  the  ti-yptic  digestion  of 
fibrin.  Drechsel  '  also  found  diamidoacetic  acid  amongst  the 
cleavage  products  of  casein. 

Proteids  are  decomj)osed  by  the  action  of  proteolytic  enzymes  in 
the  presence  of  water.  First  proteid  bodies  of  lower  molecular 
weight  are  formed — albumoses  and  peptones — and  then  on  further 
decomposition  amido-acids  such  as  leucin,  tyrosin,  and  aspartic 
acid.     Both  lysin  and  lysatinin  may  be  produced  on  far-reaching 

>  Annal.  d.  Chem.  u.  Pbarm.,  Bdd.  159  and  169. 

^Ber.  d   deutscli.  cliem.  Gesellscli.,  Bd.  16. 

'  Sitzungsber.  d.  matb.-pliys.  Klasse  der  k.  saclis.  Gesellsch.  d.  Wisseii- 
schaften.     1889. 

■*  Drechsel  gives  a  complete  review  of  his  own  and  his  pupils  Fischer, 
Siegfried  and  Hedin's  investigations  on  this  subject  in  Du  Bois-Reymond's 
Archiv,  1891  :  "Der  Abbau  der  Eiweissstoffe." 

*Ber.  d.  k.  sachs.  Gesellsch.  d.  Wissensch.,  1892. 


22  THE  PROTEIN  SUBSTANCES. 

decomposition  (in  tryptic  digestion).  On  the  extensive  decomposi- 
tion a  cliromogen  may  also  be  formed,  which  gives  a  violet  color 
with  chlorine-  or  bromine-water.  This  chromogen,  which  is  formed 
in  all  far-reaching  decompositions  of  proteids  where  lencin  and 
tyrosin  are  formed,  is  called  proteinoc]iro7nogen  by  STADELMAisrisr ' 
and  tryptophan  by  Neumeister."  JSTencki  '  considers  this  chromo- 
gen as  the  mother  substance  of  various  animal  pigments.  ISTEisrcKi  * 
has  found  on  the  addition  of  bromine  to  the  digestive  fluid  contain- 
ing proteinochromogen  that  at  least  two  different  bodies  containing 
different  quantities  of  bromine  are  produced.  Both  bodies  show, 
although  not  obtained  quite  pure,  a  close  relationship  to  certain 
animal  pigments  in  regard  to  elementary  composition.  One  stands 
close  to  haematoporphyrin,  or  bilirubin,  and  the  other  to  the  animal 
melanins. 

A  great  many  substances  are  produced  in  the  putrefaction  of 
proteids.  First  the  same  bodies  as  are  formed  in  the  decomposition 
by  means  of  proteolytic  enzymes  are  produced,  and  then  a  further 
decomposition  occurs  with  the  formation  of  a  large  number  of 
bodies  belonging  to  both  the  alipathic  and  aromatic  series.  Belong- 
ing to  the  first  series  we  have  ammonium  salts  of  volatile  fatty 
acids,  such  as  caproic,  valerianic,  and  butyric  acids,  also  carbon 
dioxide,  methane,  hydrogen,  sulphuretted  hydrogen,  methyl- 
mercaptan,*  and  others.  The  ptomaines  also  belong  to  these 
products  and  are  probably  formed  by  very  different  chemical 
processes  or  even  syntheses. 

E.  Salkowski  '  divides  the  putrefactive  products  of  the  aro- 
matic series  into  three  groups:  (a)  the  phenol  group,  to  which 
tyrosin,  the  aromatic  oxy-acids,  phenol,  and  cresol  belong;  {h)  the 
phenyl  group,  including  phenylacetic  acid  and  phenylpropionic 
acid;  and  lastly  (c)  the  indol  group,  which  includes  indol,  skatol, 
and  skatolcarbonic  acid.  These  various  aromatic  products  are 
formed  during  the  putrefaction  with  access  of  air.  JSTencki  and 
Bovet'  obtained  only  p.-oxyphenylpropionic  acid,  phenylpropionic 
acid,  and   skatolacetic   acid   on   the   putrefaction  of   proteids   by 

1  Zeitschr.  f .  Biologie,  Bd.  26. 

2/WfZ.,  S.  339. 

'  Schweizerische  Wochenschr.  f.  Pharmacie,  1891. 

*  Ber.  d.  deutscli.  cliem.  Gesellsch. ,  Bd.  28. 

'See  Nencki  and  Sieber  :  Monatshefte  f.  Chem.,  Bd.  10. 

« Zeitschr.  f.  pbysiol.  Chem.,  Bd.  12,  S.  215. 

'Monatshefte  f.  Chem.,  Bd.  10. 


CLEAVAGE  PRODUCTS  OF  PORTEIDS.  23 

anaerobic  schizomycetes  in  the  absence  of  oxygen.  These  three 
acids  are  produced  by  the  action  of  nascent  hydrogen  on  the  corre- 
sponding amido-acid,  namely,  tyrosin,  phenyLamidopropionic  acid, 
and  skatolamidoacetic  acid,  and  these  three  last-mentioned  amido- 
acids  exist,  according  to  Nencki,  preformed  in  the  proteid  mole- 
cule. 

On  the  putrefaction  of  proteids,  as  well  as  their  decomposition 
by  means  of  acids  or  alkalies  and  also  by  certain  enzymes,  among 
other  products  amido-acids  are  produced,  and  these  have  a  certain 
significance  for  the  probable  formation  of  the  proteids.  It  is  more 
than  likely  that  in  the  synthesis  of  proteids  in  the  plant  from  the 
ammonia  or  the  nitric  acid  of  the  soil,  amido-acids  or  acid  amids, 
among  which  asparagin  plays  an  important  role,  are  produced ;  and 
from  these  the  albuminous  bodies  are  derived  by  the  influence  of 
glucose  or  other  non-nitrogenized  combinations. 

Since  Grimaux  '  was  able  to  prepare  by  synthetical  means  from 
amido-acids  bodies  which  in  certain  regards  were  similar  to  pro- 
tein substances,  so  later  Schutzenberger,''  by  heating  a  mixture 
of  leucines  and    leuceines  with  urea   and  phosphoric  anhydride, 
obtained  a  substance  which  was  so  similar  to  peptone  in  its  behavior 
with   several   reagents   that    it   was   called    2^seuclope])toiie.      The 
synthetical  preparation  of  protein-like  substances  by  Lilienfeld 
and  WoLKOWicz '  in  Kossel's  laboratory  is  of  great  importance. 
The  experiments  started    from   the   observation  of  Curtius  and 
Goebel   that  amidoacetic  acid  ethylester  readily  splits  with   the 

PO  IVTT    PFT 

separation  of  a  base  whose  formula  is  probably  NH<^,q'-j^jj^'qjj» 

according  to  Lilienfeld  and  Wolkowicz,  and  that  this  base  or 
its  carbonate,  when  warmed  with  water,  is  transformed  into  a 
flocculent  body  similar  to  gelatine.  This  body  behaves  with  reagents 
and  also  in  regard  to  elementary  composition  exactly  like  gelatine, 
and  its  combination  with  hydrochloric  acid  has  the  same  composi- 
tion as  glutinpeptone-hydrochloride  as  prepared  by  Paal.  On  the 
condensation  of  other  amido-acid  esters,  namely,  the  amido-acid 
ester  of  leucin  and  tyrosin  with  amidoacetic  acid  elthylester, 
Lilienfeld  and  Wolkowicz  have  been  able  to  prepare  a  substance 
which,  as  far  as  investigated,  does  not  differ  in  any  regard  from  the 

'Compt.  rend.,  Tome  93,  and  Bull,  de  la  soc  chim..  Tome  42. 

'Compt.  rend.,  Tome  106  and  112. 

»Du  Bois-Reymond's  Arcb.,  1894,  physiol.  Abtb.,  S.  383  and  555. 


24  THE  PROTEIN  SUBSTANCES. 

peptones  or  albumoses  except  in  the  lack  of  salphnr.  They  have 
also  prepared  synthetically,  by  means  of  a  method  not  completely 
described,  a  body  which  acts  like  native  albumin  coagulated  by 
heat. 

By  the  oxidation  of  albumin  in  acid  solutions,  volatile  fatty  acids,  their 
aldehydes,  nitriles,  ketones,  as  well  as  benzoic  acid  are  obtained,  also  hydrocyanic 
acid  by  oxidizing  with  potassium  dichromate  and  acid.  Nitric  acid  gives  various 
nitro-products,  such  as  xanthoproteic  acid  (van  der  Pant's),  trinitroalbumin 
(LOEW)  or  oxyuitroalbumin,  nitrobenzoic  acid,  and  others.  With  aqua  regia 
fumaric  acid,  oxalic  acid,  chlorazol.  and  other  bodies  are  produced.  By  the 
action  of  bromine  under  strong  pressure  a  large  number  of  derivatives  are 
obtained,  such  as  bromanil  and  tribromacetic  acid,  bromoform,  leucin,  leucin- 
imid,  oxalic  acid,  tribromamido-benzoic  acid,  peptone,  and  bodies  similar  to 
humus. 

B3'  the  dry  distillation  of  albumin  we  obtain  a  large  number  of  decomposi- 
tion products  of  a  disagreeable  burnt  odor,  and  a  porous  glistening  mass  of 
carbon  containing  nitrogen  is  left  as  a  residue.  The  products  of  distillation  are 
partly  an  alkaline  liquid  which  contains  ammonium  carbonate  and  acetate, 
ammonium  sulphide,  ammonium  cyanide,  an  inflammable  oil  and  other  bodies, 
and  a  brown  oil  which  contains  hydrocarbons,  nitrogenized  bases  belonging  to 
the  aniline  and  pyridine  series,  and  a  number  of  unknown  substances. 

It  is  impossible  here  to  discuss  all  the  products  obtained  by  the 
action  of  different  reagents  on  the  albumins,  but  from  the  above- 
described  decomposition  products  from  proteids  it  is  clear  that  the 
products  belong  in  part  to  the  fatty  and  in  part  to  the  aromatic  series. 
Observers  are  not  decided  whether  one  or  more  aromatic  groups 
,exist  preformed  in  the  proteid  molecule.  According  to  JSTencki 
the  proteids  contain  three  aromatic  groups  as  mentioned  above:  the 
tyrosin  (oxyphenylamidopropionic  acid),  the  phenylamidopropionic 
acid,  and  the  skatolamidoacetic  acid.  Malt  '  considers  it  not 
necessary  to  recognize  more  than  one  aromatic  group  in  the  proteid 
molecule. 

By  the  oxidation  of  albumin  by  means  of  potassium  permanganate,  Malt 
obtained  an  acid,  oxyprotosulphonic  acid,  C  51.21  ;  H  6.89  ;  N  14.59  ;  S  1.77  ;  0 
25.54,  which  is  not  a  product  of  splitting,  but  an  oxidation  product  in  which 
the  group  SH  is  changed  into  SOj.OH.  This  acid  does  not  give  the  proper  color 
reaction  with  Millon's  reagent  caused  by  aromatic  monohydroxyl  derivatives 
(see  below),  nor  does  it  yield  the  ordinary  aromatic  splitting  products  of  the 
proteids.  Still  the  aromatic  group  is  not  absent,  but  it  seems  to  be  in  another 
binding  from  that  in  ordinary  albumin.  On  oxidizing  with  potassium  dichro- 
mate and  acid  this  group  appears  as  benzoic  acid,  and  on  fusing  with  alkali 
benzol  is  given  off. 

The  animal  albuminous  bodies  are  odorless,  tasteless,  and 
ordinarily  amorphous.  The  crystalloids  (DoTTEEPLATTCHEisr) 
occurring  in  the  eggs  of  certain  fishes  and  amphibians  do  not 
consist  of  pure  proteids,  but  of  proteids  containing  large  amounts 

'  Sitzungsber.  d.  k.  Akad.  d.  Wissensch.  Wien,  Abth.  II,  1885,  and  Abth, 
II,  1888.     Also  Monatshefte  f.  Chem.,  Bdd.  6  and  9. 


PROPERTIES  OF  PROTEIDS.  25 

of  lecithin,  which  seems  to  be  combiued  with  mineral  substances. 
Cr^'Stalline  proteids'  have  been  prepared  from  seeds  of  various  plants, 
and  lately  crystallized  animal  proteids  have  been  prepared  by 
HoFMEiSTER."  In  the  dry  condition  the  albuminous  bodies  appear 
as  a  white  powder,  or  when  in  thin  layers  as  yellowish,  hard,  trans- 
parent plates.  A  few  are  soluble  in  water,  others  only  soluble  in 
salt  or  faintly  alkaline  or  acid  solutions,  while  others  are  insoluble 
in  these  solvents.  All  albuminous  bodies  when  burnt  leave  an  ash, 
and  it  is  therefore  questionable  whether  there  exists  any  proteid 
body  which  is  soluble  in  water  without  the  aid  of  mineral  sub- 
stances. Nevertheless  it  has  not  been  thus  far  successfully  proved 
that  a  native  albuminous  body  can  be  prepared  perfectly  free  from 
mineral  substances  without  changing  its  constitution  or  its  proper- 
ties.^ The  albuminous  bodies  are  in  most  cases  strong  colloids. 
They  diffuse,  if  at  all,  only  very  slightly  through  animal  membranes 
or  j)archment-paper,  and  the  proteids  therefore  have  a  very  hi^li 
osmotic  equivalent.  All  albuminous  bodies  are  optically  active  and 
turn  the  ray  of  polarized  light  to  the  left. 

On  heating  a  proteid  solution  it  is  changed,  the  temperature 
necessary  depending  upon  the  proteid  present,  and  with  proper 
reactions  of  the  solution  and  under  favorable  external  conditions — 
as,  for  example,  in  the  presence  of  neutral  salts — most  proteids 
separate  in  the  solid  state  as  "  coagulated  "  proteids.  The  different 
temperatures  at  which  various  proteids  coagulate  in  neutral  salt 
solutions  give  in  many  cases  a  good  means  of  detecting  and  separat- 
ing these  various  bodies.  The  views  in  regard  to  the  use  of  these 
means  are  divided.' 

The  general  reactions  for  the  proteids  are  very  numerous,  but 
only  the  most  important  will  be  given  here.  To  facilitate  the  study 
of  these  they  have  been  divided  into  the  two  following  groups: 

1  See  Maschke,  Journ.  f.  prakt.  CLem.,  Bd.  74  ;  Dreclisel,  ibid.  (N.  F.),  Bd. 
19  ;  Grlibler,  ibid.  (N  F,),  Bd.  23  ;  Ritthausen,  ibid.  (N.  F  ),  Bd.  25  ;  Sclimiede- 
berg,  Zeitsclir.  f.  physiol.  Chem.,  Bd.  1  ,  Weyl,  ibid.,  Bd.  1. 

'  Zeitschr.  f.  pliysiol.  Chem.,  !dd.  14  and  16. 

'  See  E.  Harnack,  Ber.  d.  deutsch.  cliem.  Gesellscb. ,  Bdd.  22,  23,  25;  Werigo, 
Pfluger's  Archiv.  Bd.  48. 

••See  Halliburton,  Journ.  of  Physiol.,  Vols.  5  and  11  ,  Corin  and  Berard, 
Bull,  de  I'Acad,  roy.  de  Belg.,  15  ;  Haycraft  and  Duggan,  Brit.  Med.  Journ., 
1890,  and  Proc.  Roy.  Soc.  Ed.,  1889  ;  Corin  and  Ansiaux,  Bull,  de  I'Acad.  roy. 
de  Belg.,  Tome  21  ;  L.  Fredericq,  Centralbl.  f.  Physiol.,  Bd.  3  ;  Haycraft,  ibid., 
Bd.  4  ;  Hewlett,  Journ.  of  Physiol.,  Vol.  13. 


26  THE  PROTEIN  SUBSTANCES. 

A.  Precipitation  Reactions  of  the  Proteid  Bodies. 

1.  Coagulation  Test.  An  alkaline  proteid  solution  does  not 
coagulate  on  boiling,  a  neutral  solution  only  partly  and  incom- 
pletely, and  the  reaction  must  therefore  be  acid  for  coagulation. 
The  neutral  liquid  is  first  boiled  and  then  the  proper  amount  of 
acid  added  carefully.  A  flocculent  precipitate  is  formed,  and  if 
properly  done  the  filtrate  should  be  water-clear.  If  dilute  acetic 
acid  be  used  for  this  test,  the  liquid  must  first  be  boiled  and  then 

1,  2,  or  3  drops  of  acid  added  to  each  10-15  c.c,  depending  on  the 
amount  of  proteid  present,  and  boiled  before  the  addition  of  each 
drop.  If  dilute  nitric  acid  be  used,  then  to  10-15  c.c.  of  the  pre- 
viously boiled  liquid  15-20  drops  of  the  acid  must  be  added.  If 
too  little  nitric  acid  be  added  a  soluble  combination  of  the  acid  and 
proteid  is  formed  which  is  precipitated  by  more  acid.  A  proteid 
solution  containing  a  small  amount  of  salts  must  first  be  treated  with 
about  Ifo  NaCl,  since  the  heating  test  may  fail,  especially  on  using 
acetic  acid,  in  the  presence  of  only  a  slight  amount  of  proteid. 

2.  Behavior  toivards  Mineral  Acids  at  Ordinary  Temper atiires. 
The  proteids  are  precipitated  by  the  three  ordinary  mineral  acids 
and  by  metaphosphoric  acid,  but  not  by  orthophosphoric  acid.  If 
nitric  acid  be  placed  in  a  test  tube  and  the  albumin  solution  be 
allowed  to  flow  gently  thereon,  a  white,  opaque  ring  of  precipitated 
albumin  will  form  where  the  two  liquids  meet  (Heller's  albumin 
test).  3.  Preciintation  hy  Metallic  Salts.  Copper  sulphate,  neu- 
tral and  basic  lead  acetate  (in  small  amounts),  mercuric  chloride, 
and  other  salts  precipitate  albumin.  On  this  is  based  the  use  of 
albumins  as  antidotes  in  poisoning  by  metallic  salts.  4.  Precipi- 
tation hy  Ferro-  or  Femcyanide  of  Potassium  m  Acetic  Acid 
Solution.  In  these  tests  the  relative  quantities  of  reagent,  proteid, 
or  acid  do  not  interfere  with  the  delicacy  of  the  test.  5.  Precipi- 
tation hy  Neutral  Salts,  such  as  Na,,SO^  or  NaCl,  when  added  to 
saturation  to  the  liquid  acidified  with  acetic  acid  or  hydrochloric 
acid.  6.  Precipitation  hy  AlcoJiol.  The  solution  must  not  be 
alkaline,  but  must  be  either  neutral  or  faintly  acid.  It  must,  at 
the  same  time,  contain  a  sui!icient  quantity  of  neutral  salts. 
7.  Precipitation  hy  Tannic  Acid  in  acetic-acid  solutions.  The 
absence  of  neutral  salts  or  the  presence  of  free  mineral  acids  may 
not  cause  the  precipitate  to  appear,  but  after  the  addition  of  a  suffi- 
cient quantity  of  sodium  acetate  the  precipitate  will  in  both  cases 


REACTIONS  FOR  PROTEIDS.  27 

appear.  8.  Precipitation  by  Phospho-tutigstic  or  Phospho-molyhdic 
Acids  in  the  presence  of  free  mineral  acids.  Potassium-merctiric 
iodide  and  potassium-hismuth  iodide  precipitate  albumin  solutions 
acidified  with  hydrochloric  acid.  9.  Precipitation  by  Picric  Acid 
in  solutions  acidified  by  organic  acids.  10.  Precipitation  by  Tri- 
chloracetic Acid '  in  'l-ofo  solution. 

B.  Color  Reactions  for  Proteid  Bodies. 

1.  Millon''s  reaction.^  A  solution  of  mercury  in  nitric  acid 
containing  some  nitrous  acid  gives  a  precipitate  witli  proteid  solu- 
tions which  at  the  ordinary  temperature  is  slowly,  but  at  the  boil- 
ing-point more  quickly,  colored  red;  and  the  solution  may  also  be 
colored  a  feeble  or  bright  red.  Solid  albuminous  bodies,  when 
treated  by  this  reagent,  give  the  same  coloration.  This  reaction, 
which  depends  on  the  presence  of  the  aromatic  group  in  the  proteid, 
is  also  given  by  tyrosiu  and  other  benzol  derivatives  with  a  hydroxyl 
group  in  the  benzol  nucleus.'  2.  Xanthoproteic  reaction.  With 
strong  nitric  acid  the  albuminous  bodies  give,  on  heating  to  boiling, 
yellow  flakes  or  a  yellow  solution.  After  saturating  with  ammonia 
or  alkalies  the  color  becomes  orange-yello\\^.  3.  Adamhieivicz'' 
reaction.  If  a  little  proteid  is  added  to  a  mixture  of  1  vol.  concen- 
trated sulphuric  acid  and  2  vols,  glacial  acetic  acid  a  reddish-violet 
color  is  obtained  slowly  at  ordinary  temperatures,  but  more  quickly 
on  heating.  Gelatine  does  not  give  this  reaction,  -t.  Biuret  test. 
If  a  proteid  solution  be  first  treated  with  caustic  potash  or  soda  and 
then  a  dilute  copper  sulphate  solution  be  added  drop  by  drop,  first 
a  reddish,  then  a  reddish-violet,  and  lastly  a  violet-blue  color  is 
obtained.  5.  Proteids  are  soluble  on  heating  with  concentrated 
hydrochloric  acid,  producing  a  violet  color,  and  when  they  are  pre- 
viously boiled  with  alcohol  and  then  washed  with  ether  (Lieber- 
MANN  *)  they  give  a  beautiful  blue  solution.  6.  With  concentrated 
sulphuric  acid  and    sugar   (in   small   quantities)    the   albuminous 

'  F.  Obermayer,  Wiener  med.  Jahrbliclier,  1888. 

'The  reagent  is  obtained  iu  the  following  way  ;  1  pt.  mercury  is  dissolved 
in  2  pts.  of  nitric  acid  (of  sp.  gr.  1,42),  first  when  cold  and  later  by  warming. 
After  complete  solution  of  the  mercury  add  1  volume  of  the  solution  to  2  vol- 
lumes  of  water.  Allow  this  to  stand  a  few  hours  and  decant  the  supernatant 
liquid. 

^  See  O.  Nasse,  Sitzungsber.  d.  Naturforsch.  Gesellsch.  zu  Halle,  1879. 

*Centralbl.  f.  d.  med.  Wissensch.,  1887. 


28  THE  PROTEIN  SUBSTANCES. 

bodies  give  a  beautiful  red  coloration.     These  color  reactions  apply 
to  all  albuminous  bodies. 

Many  of  these  color  reactions  are  obtained  as  sliown  by  Salkowski  '  by  tlie 
aromatic  splitting  products  of  the  proteids.  Millon's  reaction  is  only  obtained 
by  the  substances  of  the  phenol  group  ;  the  Xanthoproteic  reaction  by  the 
phenol  group  and  skatol  or  skatolcarbonic  acid.  Adamkiewicz's  reaction  is 
only  given  by  the  indol  group,  especially  skatolcarbonic  acid.  Liebermann's 
reaction  is  not  given  by  any  of  the  aromatic  splitting  products. 

The  delicacy  of  the  same  reagent  differs  for  the  different 
albuminous  bodies,  and  on  this  account  it  is  impossible  to  give  the 
degree  of  delicacy  for  each  reaction  for  all  albuminous  bodies.  Of 
the  precipitation  reactions  Heller's  test  (if  we  eliminate  the 
peptones  and  certain  albumoses)  is  recommended  in  the  first  place 
for  its  delicacy,  though  it  is  not  the  most  delicate  reaction,  and 
because  it  can  be  performed  so  easily.  Among  the  precipitation 
reactions,  that  with  basic  lead  acetate  (when  carefully  and  exactly 
executed)  and  the  reactions  6,  7,  8,  and  9  are  the  most  delicate. 
The  color  reactions  1  to  4  show  great  delicacy  in  the  order  in  which 
they  are  given. 

No  proteid  reaction  is  in  itself  characteristic,  and,  therefore,  in 
testing  for  proteids  one  reaction  is  not  sufficient,  but  a  number  of 
precipitation  and  color  reactions  must  be  employed. 

For  the  qnantitative  estimation  of  coagnlable  proteids  the 
determination  by  boiling  with  acetic  acid  can  be  performed  with 
advantage  since,  by  operating  carefully,  it  gives  exact  results. 
Treat  the  proteid  solution  with  a  l-2fo  common-salt  solution,  or 
if  the  solution  contains  large  amounts  of  proteid  dilute  with  the 
proper  quantity  of  the  above  salt  solution,  and  then  carefully 
neutralize  with  acetic  acid.  Now  determine  the  quantity  of  acetic 
acid  necessary  to  completely  precipitate  the  proteids  in  small  meas- 
ured portions  of  the  neutralized  liquid  which  have  previously  been 
heated  on  the  water-bath,  so  that  the  filtrate  does  not  respond  with 
Heller's  test.  Now  warm  a  larger  weighed  or  measured  quantity 
of  the  liquid  on  the  water-bath,  and  add  gradually  the  required 
quantity  of  acetic  acid,  with  constant  stirring,  and  continue  the 
heat  for  some  time.  Filter,  wash  with  water,  extract  with  alcohol 
and  then  with  ether,  dry,  weigh,  incinerate  and  weigh  again.  "With 
proper  work  the  filtrate  should  not  give  Heller's  test.  This 
method  serves  in  most  cases,  and  especially  so  in  cases  where  other 
bodies  are  to  be  quantitatively  estimated  in  the  filtrate. 

The  precipitation  by  means  of  alcohol  may  be  used  in  the 
quantitative  estimation  of  proteids.  The  liquid  is  first  carefully 
neutralized,  treated  with  some  NaCl  if  necessary,  and  then  alcohol 

'  Zeitschr.  f.  physiol.  Chem.,  Bd.  12,  S.  215. 


METHODS  OF  ESTIMATIOX.  29 

added  until  the  solution  contains  70-80  vol.  per  cent  anhydrous 
alcohol.  The  precipitate  is  collected  on  a  filter,  extracted  with 
alcohol  and  ether,  dried,  weighed,  incinerated  and  again  weighed. 
This  method  is  only  applicable  to  liquids  which  do  not  contain 
any  other  substances,  like  glycogen,  which  are  insoluble  in  alcohol. 

In  both  these  methods  small  quantities  of  proteids  may  remain 
in  the  filtrates.  These  traces  may  be  determined  as  follows:  Con- 
centrate the  filtrate  sufficiently,  remove  any  separated  fat  by 
shaking  with  ether,  and  then  precipitate  with  tannic  acid. 
Approximately  63f^  of  the  tannic  acid  precipitate,  washed  with  cold 
water  and  then  dried,  may  be  considered  as  proteid. 

Good  results  are  also  obtained  by  the  following  method  as  sug- 
gested by  Devoto.'  The  liquid  is  treated  with  80  gms.  crystallized 
ammonium  sulphate  for  every  100  c.c.  of  fluid  and  warmed  on  the 
water-bath  until  the  salt  dissolves.  Then  ^ilace  the  vessel  in  steam 
for  30— 10  minutes  to  2  hours,  collect  the  finely  divided  precipitate 
on  a  filter,  wash  with  water  until  free  from  sulphates,  extract  with 
alcohol  and  ether,  dry  and  proceed  as  ordinarily.  This  method 
does  not  give  quite  exact  results  with  blood  or  fluids  containing 
blood,  but  otherwise  it  seems  to  be  very  serviceable. 

The  quantitative  estimation  of  proteids  by  means  of  precipitat- 
ing with  copper  sulphate  cannot  be  used  in  all  cases.  The  same  is 
true  for  the  estimation  by  means  of  the  polariscope,  which  does  not 
give  sufficiently  accurate  results. 

The  removal  of  proteids  from  a  solution  may  in  most  cases  be 
performed  by  boiling  with  acetic  acid.  Small  amounts  of  j^roteid 
which  remain  in  the  filtrates  may  be  separated  by  boiling  with 
freshly  precipitated  lead  carbonate  or  with  ferric  acetate,  as 
described  in  Chapter  XV  (on  the  urine).  If  the  liquid  cannot  be 
boiled,  the  proteid  may  be  precipitated  by  the  very  careful  addition 
of  lead  acetate,  or  by  the  addition  of  alcohol.  If  the  liquid  con- 
tains substances  which  are  precipitated  by  alcohol,  such  as  glycogen, 
then  the  proteid  may  be  removed  by  the  alternate  addition  of 
potassium-mercuric  iodide  and  hydrochloric  acid  (see  Chapter  VIII, 
on  Glycogen  Estimation). 

Synopsis  of  the  Most  Important  Properties  of  the  Diflferent  Chief 
Groups  of  Proteids. 

Those  proteids  which  occur  formed,  in  the  ordinary  sense,  in 
the  animal  fluids  and  tissues,  and  which  can  be  isolated  from  these 
without  losing  their  original  properties  by  different  chemical  means, 
are  called  native  proteids.  New  modifications,  with  other  prop- 
erties, may  be  obtained  from  these  native  proteids  by  the  action 
of  heat,  various  chemical  reagents,  such  as  acids,  alkalies,  alcohol, 

'Zeitschr.  f.  physiol.  Chem.,  Bd.  15,  S.  465. 


30  THE  PROTEIN  SUBSTANCES. 

and  others,  as  also  by  proteolytic  enzymes.  These  new  proteids  are 
called  MODIFIED '  peoteids,  in  contradistinction  to  the  native 
proteids.  The  albumins,  globulins,  and  nucleoalbumins,  as  given 
in  the  scheme  on  page  18,  belong  to  the  native  proteids,  while  the 
acid  and  alkali  albuminates,  albumoses,  peptones,  and  the  coagulated 
proteids  belong  to  the  modified  proteids. 

The  native  proteids  may  be  precipitated  by  sufficient  amounts 
of  neutral  salts  without  changing  their  properties,  although  the 
various  proteids  act  differently  with  different  neutral  salts.  Some 
are  precipitated  by  NaCl,  others  only  by  MgSO^,  and  still  others  by 
only  (NHJj^O^,  which  is  the  precipitant  for  nearly  all  proteids. 
These  various  properties,  as  also  the  different  solubility  in  water  and 
dilute  salt  solution,  are  used  at  the  present  time  to  differentiate 
between  the  various  proteids  and  groups,  although  it  must  be  stated 
that  these  differences  are  only  relative  and  are  often  uncertain. 

Albumins.  These  bodies  are  insoluble  in  water  and  are  not  pre- 
cipitated by  the  addition  of  a  little  acid  or  alkali.  They  are  pre- 
cipitated by  the  addition  of  large  quantities  of  mineral  acids  or 
metallic  salts.  Their  solution  in  water  coagulates  on  boiling  in  the 
presence  of  neutral  salts,  but  a  weak  saline  solution  does  not.  If 
NaCl  or  MgSO^  is  added  to  saturation  to  a  neutral  solution  in  water 
at  the  normal  temperature  or  at  +  30°  0.  no  precipitate  is  formed; 
but  if  acetic  acid  is  added  to  this  saturated  solution  the  albumin 
readily  separates.  When  ammonium  sulphate  is  added  in  substance 
to  saturation  to  an  albumin  solution  a  complete  precipitation  occurs 
at  ordinary  temperature.  Of  all  the  albuminous  bodies  the  albumins 
are  the  richest  in  sulphur,  containing  from  l.Qfo  to  2.2^. 

Globulins.  These  albuminous  bodies  are  insoluble  in  water,  but 
dissolve  in  dilute  neutral  salt  solutions.  The  globulins  are  precipi- 
tated unchanged  from  these  solutions  by  sufficient  dilution  with 
water,  and  on  heating  they  coagulate.  The  globulins  dissolve  in 
water  on  the  addition,  of  very  little  acid  or  alkali,  and  on  neutraliz- 
ing the  solvent  they  precipitate  again. 

The  solution  in  a  minimum  amount  of  alkali  is  precipitated  by 
carbon  dioxide,  but  the  precipitate  may  be  redissolved  by  an  excess 
of  the  precipitant.  The  neutral  solutions  of  the  globulins  contain- 
ing salts  are  partly  or  completely  precipitated  on  saturation  with 

'  The  word  denaturierung  as  used  by  Neumeister  and  tlie  author  is 
translated  by  the  word  modified,  as  it  best  expresses  the  meaning.  The  word 
derived  might  also  be  used. 


NUCLEO  ALBUMINS.  31 

NaCl  or  MgSO^  in  substance  at  normal  temperatures.  Tlie 
globulins  are  completely  precipitated  by  saturating  with  ammonium 
sulphate.  The  globulins  contain  an  average  amount  of  sulphur? 
not  below  1^. 

A  sharp  line  between  the  globulins  on  one  side  and  the  artificial  albuminates 
on  the  other  can  hardly  be  drawn.  The  albuminates  are,  indeed,  as  a  rule  in- 
soluble in  dilute  common-salt  solutions;  but  an  albuminate  maybe  prepared 
by  the  action  of  strong  alkali  which  is  soluble  in  commou-salt  solutions  imme- 
diately after  precipitation.  We  also  have  globulins  which  are  insoluble  in 
NaCl  after  having  been  in  contact  with  water  for  some  time. 

Nucleoalbumins.  These  bodies  are  found  widely  diffused  in 
both  the  animal  and  vegetable  kingdoms.  They  form  one  of  the 
chief  constituents  of  protoplasm,  while  the  albumins  and  in  part 
also  the  globulins  are  special  constituents  of  the  animal  juices. 
The  nucleoalbumins  are  found  in  organs  abounding  in  cells,  but 
they  also  occur  in  secretions  and  sometimes  in  other  fluids  in 
apparent  solution  as  destroyed  and  altered  protoplasm.  The 
nucleoalbumins  behave  like  rather  strong  acids;  they  are  nearly 
insoluble  in  water,  but  dissolve  easily  with  the  aid  of  a  little  alkali. 
Such  a  solution,  neutral  or,  indeed,  a  faintly  acid  one,  does  not 
coagulate  on  boiling.  The  nucleoalbumins  resemble  the  globulins 
and  the  albuminates  in  solubility  and  precijaitation  properties,  but 
differ  from  them  in  being  hardly  soluble  in  neutral  salts.  The 
most  important  difference  between  the  nucleoalbumins,  the  globu- 
lins, and  the  albuminates  is  tiiat  the  nucleoalbumins  contain 
phosphorus,  and  by  the  action  of  pepsin  hydrochloric  acid  on 
nucleoalbumins  a  phosphorized  product,  parauuclein  or  pseudo- 
nucleui,  is  split  off  which,  according  to  Liebermann,'  is  a  combi- 
nation of  albumin  with  metaphosphoric  acid.  The  nucleoalbumins 
seem  habitually  to  contain  less  sulphur  than  the  bodies  of  the  pre- 
ceding groups.     Some  iron  is  found  as  a  constant  constituent. 

The  nucleoalbumins  are  often  confounded  with  nucleoproteids 
and  also  with  phosphorized  glycoproteids.  From  the  first  class  they 
differ  by  not  yielding  any  xanthin  bodies  when  boiled  with  acids, 
and  from  the  second  group  by  not  yielding  any  reducing  substance 
on  the  same  treatment. 

Lecithalbumins.  On  the  preparation  of  certain  protein  substances  products 
are  often  obtained  containing  lecithin,  and  this  lecithin  can  only  be  removed 
with  difficulty  or  incompletely  by  a  mixture  of  alcohol  and  ether.     Ovovitellin 

'  Ber.  d.  deutsch.  chem.  CJesellsch.,  Bd.  21. 


32  THE  PROTEIN  SUBSTANCES. 

is  sucli  a  protein  body  containing  considerable  lecithiu,  and  Hoppe-Setlek  ' 
considers  it  a  combination  of  albumin  and  lecithin.  Liebermann  '^  lias  obtained 
proteids  containing  lecithin  as  an  insoluble  residue  on  the  peptic  digestion  of 
mucous  membranes  of  the  stomach,  liver,  kidneys,  lungs,  and  spleen.  He  con- 
siders them  as  combinations  of  proteid  and  lecithin  and  calls  them  lecithalhu- 
mins.  They  differ  from  the  nucleo-albumins  in  that  no  metaphosphoric  acid  is 
split  off  and  from  the  nucleo-proteids  for  the  same  reason,  and  also  in  that  they 
do  not  yield  xanthin  bases.    Further  investigations  are  necessary  on  this  subject. 

Alkali  and  Acid  Albuminates.  By  the  action  of  alkalies  all 
native  albuminous  bodies  are  converted,  with  the  elimination  of 
nitrogen  or  by  the  action  of  stronger  alkali  with  the  emission  of 
sulphur,  into  a  new  modification,  called  alkali  albuminate,  whose 
specific  rotation  is  increased  at  the  same  time.  If  caustic  alkali  in 
substance  or  in  strong  solution  be  allowed  to  act  on  a  concentrated 
proteid  solution,  such  as  blood-serum  or  egg-albumin,  the  alkali 
albuminate  may  be  obtained  as  a  solid  jelly  which  dissolves  in  water 
on  heating,  and  which  is  called  "  Lieberkuhn's  solid  alkali  albumi- 
nate." By  the  action  of  dilute  caustic  alkali  solutions  on  dilute 
proteid  solutions  we  have  alkali  albuminates  formed  slowly  at  the 
ordinary  temperature,  bat  more  rapidly  on  heating.  These  solu- 
tions may  be  modified  by  the  source  of  the  proteid  acted  upon,  and 
also  by  the  extent  of  the  action  of  the  alkali,  but  still  they  have 
certain  reactions  in  common. 

If  proteid  is  dissolved  in  an  excess  of  concentrated  hydrochloric 
acid,  or  if  we  digest  a  proteid  solution  acidified  with  1-2  p.  m. 
hydrochloric  acid  in  the  warmth,  or  digest  the  proteid  alone  with 
pepsin  hydrochloric  acid,  we  obtain  new  modifications  of  proteid 
which  indeed  may  show  somewhat  varying  properties,  but  have  cer- 
tain reactions  in  common.  These  modifications,  which  may  be 
obtained  in  a  solid  gelatinous  condition  on  sufficient  concentration, 
are  called  acid  albuminates  or  acid  albumins,  sometimes  also  syn- 
tonin,  though  we  prefer  to  call  that  acid  albuminate  syntonin  which 
is  obtained  by  extracting  muscles  with  hydrochloric  acid  of  1  p.  m. 

The  alkali  and  acid  albuminates  have  the  following  reactions  in 
common:  They  are  nearly  insoluble  in  water  and  dilute  common- 
salt  solutions  (see  page  31),  but  they  dissolve  readily  in  water  on 
the  addition  of  a  very  small  quantity  of  acid  or  alkali.  Suoh  a 
solution  or  one  nearly  neutral  does  not  coagulate  on  boiling  if 
neutral  salts  are  not  present  in  sufficient  quantity,  but  is  precipi- 

'  Hoppe-Seyler,  Med.  chem.  Untersuch.,  1868 ;  also  Zeitschr.  f.  physiol. 
Chem.,  Bd.  13,  S.  479. 

2  Pfliiger's  Archiv,  Bdd.  50  and  54. 


ALBUM08E8  AND  PEPTONES,  83 

tated  at  the  normal  temperature  on  neutralizing  the  solvent  by  an 
alkali  or  an  acid.  A  solution  of  an  alkali  or  acid  albuminate  in 
acid  is  easily  precipitated  on  saturating  with  NaCl,  but  a  solution 
in  alkali  is  precipitated  with  difficulty  or  not  at  all,  according  to 
the  amount  of  alkali  it  contains.  The  nearly  neutral  solutions  are 
precipitated  by  mineral  acids  in  excess,  also  by  many  metallic  salts» 
Notwithstanding  this  agreement  in  the  reactions,  the  acid  and 
alkali  albuminates  are  essentially  different,  and  by  dissolving  an 
alkali  albuminate  in  some  acid  no  acid  albuminate  solution  is 
obtained,  nor  is  an  alkali  albuminate  formed  on  dissolving  an  acid 
albuminate  in  water  by  the  aid  of  a  little  alkali.  The  alkali 
albuminates  are  relatively  strong  acids.  They  may  be  dissolved  in 
water  with  the  addition  of  CaCOj,  with  the  elimination  of  CO,,, 
which  does  not  occur  with  typical  acid  albuminates,  and  they  show 
in  opposition  to  the  acid  albuminates  also  other  variations  which 
stand  in  connection  with  their  strongly  marked  acid  nature.  Dilute 
solutions  of  alkalies  act  more  energetically  on  proteids  than  do  acids 
of  corresponding  concentration.  In  the  first  case  a  part  of  the 
nitrogen,  and  often  also  the  sulphur,  is  split  off,  and  from  this 
property  we  may  obtain  an  alkali  albuminate  by  the  action  of  an 
alkali  upon  an  acid  albuminate;  but  we  cannot  obtain  an  acid 
albuminate  by  the  reverse  reaction.     (K.  Morner.') 

The  preparation  of  the  albuminates  has  been  given  above.  By 
the  action  of  alkalies  or  acids  upon  an  proteid  solution  the  corre- 
sponding albuminate  may  be  precipitated  by  neutralizing  with  acid 
or  alkali.  The  washed  precipitate  is  dissolved  in  water  by  the  aid 
of  a  little  alkali  or  acid,  and  again  precipitated  by  neutralizing  the 
solvent.  If  this  precipitate  which  has  been  washed  in  water  is 
treated  with  alcohol  and  ether,  the  albuminate  will  be  obtained  in 
a  pure  form. 

Albumoses  and  Peptones.  Peptones  are  designated  as  the  final 
products  of  the  decomposition  of  albuminous  bodies  by  means  of 
proteolytic  enzymes,  in  so  far  as  these  final  products  are  still  true 
albuminous  bodies,  while  we  designate  as  albumoses,  proteoses,  or 
propeptones  the  intermediate  products  produced  in  the  peptoniza- 
tion of  proteids  in  so  far  as  they  are  substances  not  similar  to 
albuminates. 

Albumoses  and  peptones  may  also  be  produced  by  the  hydrolytic 
decomposition  of  the  proteids  with  acids  or  alkalies,  also  by  the 

'  Pfliiger's  Arc  hi  v,  Bd.  17. 


34  TBE  PMOTEm  SUBSTANCES. 

putrefaction  of  the  same.  They  may  also  be  formed  in  very  small 
quantities  as  by-prodncts  in  the  investigations  of  animal  fluids  and 
tissues,  and  the  question  to  what  extent  these  exist  preformed  under 
physiological  conditions  requires  very  careful  investigation. 

Between  the  peptones  which  represent  the  last  splitting  products 
^nd  those  albumoses  which  stand  closest  to  the  original  proteids  we 
have  undoubtedly  a  series  of  intermediate  products.  Under  such 
circumstances  it  is  a  difficult  problem  to  try  to  draw  a  sharp  line 
between  the  peptone  and  the  albumose  group,  and  it  is  just  as  diffi- 
cult to  define  our  conception  of  peptones  and  albumoses  in  an  exact 
.and  satisfactory  manner. 

The  albumoses  have  been  considered  as  those  albuminous  bodies 
whose  neutral  or  faintly  acid  solutions  do  not  coagulate  on  boiling 
and  which,  to  distinguish  them  from  peptones,  were  characterized 
chiefly  by  the  following  properties.  The  watery  solutions  are  pre- 
cipitated at  the  ordinary  temperature  by  nitric  acid  as  well  as  by 
acetic  acid  and  potassium  ferrocyanide,  and  this  precipitate  has  the 
peculiarity  of  disappearing  on  heating  and  reappearing  on  cooling. 
If  a  solution  of  albumoses  is  saturated  with  NaCl  in  substance,  the 
albumoses  are  partly  precipitated  in  neutral  solutions,  but  on  the 
addition  of  acid  saturated  with  the  salt  they  completely  precipitate. 
This  precipitate,  which  dissolves  on  warming,  is  a  combination  of 
albumose  with  the  acid. 

We  formerly  designated  as  peptone  those  proteid  bodies  which 
are  readily  soluble  in  water  and  which  do  not  coagulate  by  heat, 
whose  solutions  are  precipitated  neither  by  nitric  acid,  nor  by  acetic 
acid  and  potassium  ferrocyanide,  nor  by  neutral  salts  and  acid. 

The  reactions  and  properties  which  the  albumoses  and  peptones 
had  in  common  were  formerly  considered  as  the  following :  They 
give  all  the  color  reactions  of  the  proteids,  but  with  the  biuret  test 
they  give  a  more  beautiful  red  color  than  the  ordinary  proteids. 
They  are  precipitated  by  ammoniacal  lead  acetate,  by  mercuric 
chloride,  tannic,  phospho-tungstic,  phospho-molybdic  acids,  potas- 
sium-mercuric iodide  and  hydrochloric  acid,  and  lastly  by  picric 
acid.  They  are  precipitated  but  not  coagulated  by  alcohol,  namely, 
the  precipitate  obtained  ii'  soluble  m  water  even  after  being  in  con- 
tact with  alcohol  for  a  long  time.  The  albumoses  and  peptones 
also  have  a  greater  diffusive  power  than  native  albuminous  bodies, 
and  the  diffusive  power  is  greater  the  nearer  the  questionable  sub- 
stance stands  to  the  final  product,  the  now  so-called  pure  peptone. 


ALB  U MOSES  AND  PEPTONES.  35 

These  old  views  have  undergone  an  essential  change  in  the  last 
few  years.  After  Heynsius'  '  observation  that  ammonium  sulphate 
was  a  general  precipitant  for  proteids,  also  peptone  in  the  old  sense, 
KiJHNE '  and  his  pupils  proposed  this  salt  as  a  means  of  separating 
albumoses  and  peptones.  Those  products  of  digestion  which  sepa- 
rate on  saturating  their  solution  with  ammonium  sulphate  are  con- 
sidered by  KiJHNE  and  indeed  by  most  of  the  modern  investigators 
as  albumoses,  while  those  which  remain  in  solution  are  called 
peptones  or  pure  peptone.  This  pure  peptone  is  formed  in  rela- 
tively large  amounts  in  pancreatic  digestion,  while  in  pepsin 
digestion  it  is  only  formed  in  small  quantities  or  after  prolonged 
digestion. 

According  to  Schutzenberger  '  and  Kuhne  '  the  proteids 
yield  two  chief  groups  of  new  albuminous  bodies  when  decomposed 
by  dilute  mineral  acids  or  with  proteolytic  enzymes;  of  these  the 
anti  group  shows  a  greater  resistance  to  further  action  of  the  acid 
and  enzyme  than  the  other,  namely,  the  hemi  group.  Correspond- 
ing to  these  views  Kuhne  divides  the  albumoses  into  two  chief 
groups,  the  antialbumoses  and  hemialbitmoses,  and  the  peptones  into 
two  chief  groups,  the  antipeptones  and  the  hemipeptones.  In  pepsin 
digestion  we  obtain,  besides  different  albumoses,  a  mixture  of  anti- 
and  hemipeptone,  which  mixture  Kuhne  called  amphopeptone.  In 
the  digestion  with  trypsin  (the  proteolytic  enzyme  of  the  pancreas) 
the  hemipeptone  is  further  split  into  leucin,  tyrosin,  and  other  sub- 
stances, while  the  antipeptoue  remains  unchanged.  By  the  suf- 
ficiently energetic  action  of  trypsin  only  one  peptone  is  at  last 
obtained,  the  so-called  antipeptone. 

KiJHNE  and  his  pupils,  who  have  conducted  these  complete 
investigations  on  the  albumoses  and  peptones,  classify  the  various 
albumoses  according  to  their  different  solubilities  and  precipitation 
powers.  In  the  pepsin  digestion  of  fibrin  ^  they  obtained  the  fol- 
lowing albumoses:  {a)  Heteroalhumose^  insoluble  in  water  but  soluble 
in  dilute  salt  solution;  {h)  Protalbumose,  soluble  in  salt  solution  and 

•  Pflilger's  Archiv,  Bd.  34. 

'  See  Kiihne,  Verhandl.  d.  naturhistor,  Vereins  zu  Heidelberg  (N.  F.),  3  ;  J. 
Wenz,  Zeitschr.  f.  Biologic,  Bd.  22  ;  Kiiline  and  Chittenden,  Zeitschr.  f .  Bio- 
logic, Bd.  22  ,  R.  Ncumcister,  ibid. ,  Bd.  23  ;  Kiihne,  ibid. ,  Bd.  29. 

*Bull.  de  la  soc.  chimique  de  Paris,  23. 

*See  Kiihne,  Verhandl.  d.  naturhistor.  Vereins  zu  Heidelberg  (N.  F.),  Bd. 
1,  and  Kiihne  and  Chittenden,  Zeitschr.  f.  Biologic,  Bd.  19. 

'  See  Kiihne  and  Chittenden,  Zeitschr.  f .  Biologie,  Bd.  30. 


36  TEE  PROTEIN  SUBSTANCES. 

water.  These  two  albnmoses  are  precipitated  by  NaCl  in  neutral 
solutions,  but  not  completely.  Heteroalbumose  may  be  converted 
into  a  modification,  called  (c)  Dysalhumose,  which  is  insoluble  in 
dilate  salt  solutions  by  being  in  contact  with  water  for  a  long  time 
or  by  drying,  [d)  Deuteroalbumose  is  an  albumose  which  is  soluble 
in  water  and  dilute  salt  solution  and  which  is  incompletely  precipi- 
tated from  acid  solution  by  saturating  with  NaCl  and  not  precipi- 
tated from  neutral  solutions.  This  precipitate  is  a  combination  of 
the  albumose  with  acid  (Herth  '). 

Herth  1  claims  that  the  relative  proportion  of  acid  or  alkali,  salt,  water,  or 
albumose  in  a  solution  essentially  changes  the  solubility  and  precipitation 
power  of  the  same.  He  also  claims  that  the  occurrence  of  several  difEerent 
liinds  of  albnmoses  cannot  be  demonstrated,  because  with  one  and  the  same 
albumose,  the  above  conditions  being  changed,  its  solubilities  and  precipitating 
powers  are  changed.  Hamburger  '  found  the  same  to  be  true  from  his  inves- 
tigations. 

The  albumoses  obtained  from  different  proteid  bodies  do  not 
seem  to  be  identical,  but  differ  in  their  behavior  to  precipitants. 
Special  names  have  been  given  to  these  various  albumoses  according 
to  the  mother  proteid,  namely,  gloluloses,^  vitilloses,*  caseoses,^ 
myosinoses,*  etc.  These  various  albumoses  are  further  distinguished, 
Si'&proto-,  hetero-,  and  deutero-caseo&es  for  example.  All  the  albu- 
moses formed  in  the  digestion  of  animal  and  vegetable  proteid  are 
embraced  in  the  common  nsime proteoses  by  Chittenden".' 

Neumeister*  designates  as  atmidalbumose  that  body  which  is  obtained  by 
the  action  of  superheated  steam  on  fibrin.  At  the  same  time  he  also  obtained 
a  substance  called  atmidalbumin  which  stands  between  the  albuminates  and 
the  albumoses.  Chittenden  and  Frank  *  have  obtained  as  products  of  the 
action  of  superheated  steam  on  ovalbumin,  besides  a  little  peptone,  leucin,  and 
tyrosin,  two  substances,  similar  to  albumoses,  which  correspond  to  the  two 
atmid  substances  of  Neumeister,  but  differ  from  them  by  containing  a  higher 
percentage  of  carbon. 

'Monatshefte  f.  Chem.,  Bd.  5. 

i^See  Maly's  Jahresber.,  Bd.  16,  S.  20. 

^Klihne  and  Chittenden,  Zeitschr,  f.  Biologie,  Bd.  22. 

*  Neumeister,  ibid.,  Bd.  32;  Chittenden  and  Hartwell,  Journ.  of  Physiol., 
Vol.  11. 

*  Chittenden  and  Painter,  Studies  from  the  Laboratory,  etc.,  Yale  University, 
Vol.  3,  New  Haven,  1891  ;  Chittenden,  ibid.,  Vol.  3  ;  Sebelein,  Chem.  Central- 
blatt,  1890. 

« Kuhne  and  Chittenden,  Zeitschr.  f .  Biologie,  Bd.  25 ;  Chittenden  and 
Goodwin,  Journ.  of  Physiol.,  Vol.  12. 

■"  Chittenden  and  Hartwell,  Journ.  of  Physiol.,  Vol.  13. 
8  Zeitschr.  f .  Biologie,  Bd.  26. 
9 Journal  of  Physiol.,  Vol.  15. 


ALBUM0SE8  AND  PEPTONES.  37 

Of  the  soluble  albumoses  Neumeister  '  designates  protoalbu- 
mose  and  heteroalbumose  as  priinary  albumoses,  while  the  deutero- 
albumoses,  which  are  closely  allied  to  the  peptones,  he  calls 
secondary  albumoses.  As  essential  difference  between  the  primary 
and  secondary  albumoses  he  suggests  the  following: '  The  primary 
albumoses  are  precipitated  by  nitric  acid  in  salt-free  solutions,  while 
the  secondary  albumoses  are  only  precipitated  in  salt  solutions, 
while  certain  deuteroalbumoses,  such  as  deuterovitillose  and  deutero- 
myosinose,  are  only  precipitated  by  nitric  acid  in  solutions  saturated 
with  NaCl.  The  primary  albumoses  are  precipitated  from  neutral 
solutions  by  copper  sulphate  solution  (2  :  100),  also  by  NaCl  in 
substance,  while  the  secondary  albumoses  are  not.  The  primary 
albumoses  are  completely  precipitated  from  their  solution  saturated 
with  NaCl  by  the  addition  of  acetic  acid  saturated  with  salt,  while 
the  secondary  albumoses  are  only  partly  precipitated.  The  primary 
albumoses  are  readily  precipitated  by  acetic  acid  and  potassium 
ferrocyanide,  while  the  secondary  are  only  incompletely  precipitated 
after  some  time.  The  deuteroalbumoses  are  derived  from  the 
primary  albumoses  and  therefore  have  a  smaller  molecular  weight. 
Contrary  to  this  view  Kuhne  ^  has  found  that  deuterofibrinoses 
diffuse  less  readily  than  the  protofibrinose,  and  also,  according  to 
Sabanejevv,*  the  deuteroalbumose  has  a  higher  molecular  weight 
(3200)  than  the  protoalbumose  (2467-2643). 

Paal  °  has  prepared  combinations  of  peptone,  from  ovalbumin, 
with  hydrochloric  acid  in  a  manner  similar  to  that  with  gelatine. 
The  elementary  composition  of  the  different  preparations  showed 
considerable  variation,  as  did  also  the  molecular  weight.  Tiie  acid 
combining  power  of  the  hydration  products  produced  in  peptoniza- 
tion increased  with  the  progress  of  the  hydrolytic  cleavage. 
Schrotter  °  has  prepared  from  Witte's  albumose  mixture  a  crys- 
talline albumose,  separating  from  methyl  alcohol  on  cooling,  whose 
hydrochloride  contained  on  an  average  10.8^  HCl  and  whose  molec- 
ular weight  was  587-714  as  determined  by  Raoult's  method.  As 
the  electrical  conductivity  of  hydrochloric  acid  diminishes  in  pro- 

'  Zeitschr.  f .  Biologic,  Bd.  24. 
^Ibid.,  Bd.  26. 
^Ibid.,  Bd.  29. 

*Ber.  d.  deutsch.  chem.  Gesellscli.,  Bd,  26,  Ref.  p.  385. 
^Ibid.,  Bd.  27. 
.  •Monatshefte  f.  Chem..  Bd.  14. 


38  THE  PROTEIN  SUBSTANCES. 

portion  as  the  acid  is  neutralized  by  alkali,  so  Sjoqvist  '  found 
a  similar  behavior  when  hydrochloric  acid  was  neutralized  with 
proteids.  Starting  from  these  circumstances  Sjoqvist  has  studied 
the  combinations  of  proteids  with  HCl,  HNO^,  H^SO,,  and  H3PO,, 
and  has  tried  to  determine  the  chemical  equivalent  of  proteids. 
He  found  this  to  be  about  800  for  ovalbumin,  about  600  for  albu- 
mose,  and  about  250  for  peptone. 

The  true  peptones  are  exceedingly  hygroscopic,  and  when  per- 
fectly dry  sizzle  like  phosphoric  anhydride  when  treated  with 
water.  They  are  exceedingly  soluble  in  water,  diffuse  more  readily 
than  the  albumoses,  and  are  not  precipitated  by  ammonium  sulphate. 
Pure  true  peptones  are  not  precipitated  either  by  picric  acid  or  by 
potassium-mercuric  iodide  and  acid.  They  are  incompletely  pre- 
cipitated by  phospho-tungstic  or  phospho-molybdic  acids.  The 
peptones  are  precipitated  by  tannic  acid,  but  this  may  be  redis- 
solved  in  an  excess  of  the  precipitant  (Sebelien  ').  According  to^ 
Sabanejew  the  molecular  weight  of  the  peptones  is  below  400. 

As  the  so-called  true  peptones  hitherto  have  not  been  prepared 
perfectly  pure,  and  therefore  the  characteristic  properties  are  still 
not  known,  we  consider  the  behavior  to  ammonium  sulphate  as  the 
absolute  difference  between  albumoses  and  peptones.  It  is  still 
doubtful  whether  the  behavior  of  a  single  salt,  the  ammonium  sul- 
phate, yields  sufficient  basis  for  the  characterization  of  two  groups 
of  albuminous  bodies,  the  albumoses  and  peptones;  and  this  ques- 
tion is  warranted  since,  according  to  Neumeistee,  we  have  a 
deuteroalbumose  (formed  from  the  protalbumose  in  peptic  digestion) 
which  is  not  completely  precipitated  by  ammonium  sulphate.  It 
seems  that  the  transformation  of  proteids  into  peptones  takes  place 
through  a  number  of  intermediate  steps  similar  to  the  transforma- 
tion of  starch  into  dextrose  through  a  series  of  dextrins.  A  com- 
plete separation  of  these  several  intermediate  products  as  well  as 
their  purification  is  such  an  extremely  difficult  task  that  it  is  nearly 
impossible  at  present  to  say  how  far  such  a  differentiation  is 
warranted  or  feasible. 

What  relationship  do  the  albumoses  and  peptones  bear  to  the 
proteid  from  which  they  are  formed  ?  Heeth  '  has  found  that 
fibrin  albumose  and  fibrin  have  approximately  the  same  constitu- 

'  Skand.  Arch.  f.  Physiol.,  Bd.  5. 

»Chem.  Centralbl..  1890. 

^Zeitschr.  f  physiol.  Chem.,  Bd.  1,  and  Monatshefte  f.  Chein,,  Bd.  5. 


ALBUMOSES  AND  PEPTONES.  39 

tion.  KuHNE  and  Chittenden,  as  also  Chittenden  and  his 
pupils,'  have  analyzed  the  different  albumoses  from  fibrin,  globulin, 
ovalbumin,  myosin,  and  casein,  and  found  in  certain  albumoses 
an  increase  and  in  others  a  decrease  in  the  amount  of  carbon, 
nitrogen,  and  sulphur  as  compared  with  the  mother-proteid. 
From  the  results  of  their  analyses  it  has  been  found  that,  with  the; 
probable  exception  of  the  albumoses  standing  closest  to  the  peptone^ 
the  difference  in  the  constitution  of  the  original  proteids  and  the 
corresponding  albumoses  is  sometimes  in  one  direction  and  some- 
times in  another,  and  is  at  all  events  unessential. 

According  to  the  analyses  of  peptones  (in  the  old  sense)  made 
by  Maly,'  Hekth,'  and  Henningek,*  they  seem  to  have  the  same 
constitution  as  the  proteid.  According  to  the  analyses  by  Kuhne 
and  Chittenden^  of  "true"  fibrin  peptone,  part  amphopeptone 
and  part  antipeptone  prepared  by  pancreas  infusion,  this  peptone 
was  found  to  contain  about  the  same  amount  of  hydrogen  and  the 
same  or  a  greater  amount  of  nitrogen,  but  considerably  less  carbon 
than  the  albumoses.  In  his  investigations  on  casein  Chittenden 
found,  on  the  other  hand,  that  in  antipeptone  the  amount  of 
carbon  was  higher  than  in  certain  caseoses.  As  the  preparation  of 
true  peptones  in  a  pure  condition  is  accompanied  with  great  diffi- 
culty, and  as  the  peptones  (in  the  modern  sense)  analyzed  have  not 
always  behaved  as  true  peptones  towards  the  peptone  reagents  as 
described  by  Neumeister,  it  is  most  difficult  to  draw  any  positive 
conclusion  from  these  analyses.  It  seems,  nevertheless,  that 
generally  the  so-called  true  peptones  are  perhaps  somewhat  poorer 
in  carbon  than  the  corresponding  proteids. 

The  elementary  analyses  made  up  to  the  present  time  have  not 
given  us  a  positive  answer  in  regard  to  the  relationship  existing 
between  the  proteids  on  one  side  and  the  albumoses  and  peptones 
on  the  other.  The  view  that  the  peptone  formation  is  a  hydi'olytic 
splitting  is  accepted  by  Hoppe-Seyler,'  Kuhne,  Henninger,* 
and  indeed  by  recent  investigators.  In  support  of  this  view  we 
have  the  observations  of  Henninger  *  and  Hofmeister,'  according 

'  See  references  cited  page  36  by  Kiiline  and  Chittenden. 

'  Pfluger's  Archiv,  Bdd.  9  and  20. 

^Zeitschr.  f.  physiol.  Chem.,  Bd.  1,  and  Monatshefte  f.  Chem.,  Bd.  5. 

*  Comptes  rendus,  Tome  86. 

^  See  references  page  36  by  Kilhne,  Chittenden. 

*  Hoppe-Seyler,  Physiol.  Chem.     Berlin,  1881 
'Zeitschr.  f.  physiol.  Chem.,  Bd.  2. 


40  THE  PROTEIN  SUBSTANCES. 

to  which  peptones  are  converted  into  a  proteid  similar  to  albuminates 
by  the  action  of  acetic-acid  anhydride,  or  by  heating  so  that  water 
is  expelled.  According  to  other  investigators,  as  Maly,'  Herth,'' 
LoEW,*  and  others,  the  formation  of  peptone  is  a  depolymerization 
of  the  proteids.  A  third  view  is  that  proteids  and  peptones  are 
isomeric  bodies;  while  a  fourth  view  (Griessmayer '^)  claims  that 
the  proteids  consist  of  micell  groups  which  on  peptonization  are 
first  converted  into  micelli  and  then  further  into  molecules. 
Though  an  ordinary  albumin  solution  contains  micelli  or  micell 
bonds,  so  also  a  peptone  solution  contains  a  proteid  molecule. 

The  preparation  of  different  albumoses  in  a  perfectly  pure  form 
is  very  troublesome  and  accompanied  with  a  great  many  difficulties. 
Por  this  reason  there  will  be  given  here  only  the  general  methods 
by  which  the  different  albumose  precipitates  are  obtained.  If  we 
proceed  from  a  solution  of  fibrin  in  pepsin  hydrochloric  acid,  we 
first  remove  the  syntonin  or  some  coagulable  proteid  present  by  first 
neutralizing  and  then  coagulating  by  heat.  The  neutral  filtrate  is 
saturated  with  NaOl,  which  precipitates  a  mixture  of  primary 
albumoses.  This  precipitate  is  washed  with  a  saturated  NaCl  solu- 
tion, pressed  and  dissolved  in  dilute  salt  solution.  An  insoluble 
residue  remains,  which  is  called  dysalbumose.  The  solution  of  the 
primary  albumoses  is  repeatedly  and  completely  dialyzed.  Hetero- 
albumose  separates  out,  while  the  protalbumose  remains  in  solution 
and  may  be  precipitated  by  alcohol.  The  above  filtrate,  which  has 
had  the  primary  albumoses  removed  and  saturated  with  NaCl,  is 
treated  with  acetic  acid,  which  has  previously  been  saturated  with 
ISTaCl,  until  no  further  precipitate  occurs.  This  precipitate,  which 
consists  of  a  mixture  of  primary  and  secondary  albumoses,  is  filtered 
off,  the  filtrate  freed  from  salt  by  dialysis,  and  the  deutero- 
albumose  precipitated  by  ammonium  sulphate.  The  various  albu- 
moses may  also  be  precipitated  from  the  original  solution  by 
ammonium  sulj)hate,  dissolved  in  water  and  freed  from  ammonium 
-sulphate  by  means  of  dialysis,  and  then  separated  as  above  described. 

In  the  preparation  of  true  peptone  we  make  use  of  a  prolonged 
pepsin  digestion,  but  much  quicker  results  are  obtained  by  the  use 
of  trypsin  digestion.  The  albumoses  must  be  entirely  removed, 
which  is  done  by  alternately  precipitating  in  acid,  neutral  and 
alkaline  solution,  with  ammonium  sulphate.  According  to 
KuHNE^  we  proceed  in  the  following  way:  The  sufficiently  dilute 
and  neutral  solution  (free  from  albuminates  and  coagulable  proteids) 
is  first  precipitated,  while  boiling  hot,  with  ammonium  sulphate. 
On   cooling  the   precipitated  albumoses  and  crystallized   salt  are 

1  Pfluger's  Archiv,  Bd.  31. 

«See  Maly's  Jahresber.,  Bd.  14,  S.  36. 

'Zeitschr.  f.  Biologie,  Bd.  29. 


FREPARATION  OF  ALBUMOSES  AND  PEPTONES.  41 

removed  by  filtration  and  the  filtrate  heated  to  boiling,  made 
strongly  alkaline  with  ammonia  and  ammonium  carbonate,  again 
saturated  with  ammonium  sulphate  at  the  boiling  temperature. 
Remove  precipitate  by  filtration  when  cold,  heat  the  filtrate  again 
until  all  odor  of  ammonia  is  expelled,  saturate  with  ammonium 
sulphate  while  hot,  and  acidify  with  acetic  acid  and  filter  on 
cooling. 

The  filtrate  is  freed  from  a  great  part  of  the  salt  by  strongly 
concentrating  the  liquid,  allowing  it  to  cool,  and  removing  the  salt 
by  filtration.  Another  large  portion  of  the  salt  may  be  removed 
from  this  filtrate  by  the  careful  fractional  precipitation  with  alcohol, 
which  yields  an  alcoholic  solution  rich  in  peptone  with  only  a  small 
quantity  of  ammonium  salt.  This  solution  is  boiled  to  remove  the 
alcohol,  and  then  boiled  with  barium  carbonate  to  remove  the 
ammonium  sulphate.  The  filtrate  is  freed  from  excess  of  barium 
by  the  careful  addition  of  dilute  sulphuric  acid.  This  filtrate, 
which  must  not  contain  an  excess  of  sulphuric  acid,  is  now  concen- 
trated and  the  peptone  precipitated  therefrom  by  alcohol. 

For  the  detection  of  albumoses  and  peptones  in  animal  fluids  or 
in  watery  extracts  of  organs  and  tissues  we  proceed  as  follows, 
according  to  Devoto:'  The  coagulable  proteids  are  removed  by 
heating  with  as  pure  ammonium  sulphate  as  possible,  as  above 
described  (page  29).  True  peptones  (besides  deuteroalbumose  not 
precipitated)  may  be  detected  in  the  cold  filtrate  by  means  of  the 
biuret  test.  The  albumoses  are  contained  in  the  mixture  of  pre- 
cipitate and  salt  crystals  collected  on  the  filter.  The  albumoses  are 
dissolved  from  this  mixture  by  washing  with  water,  and  may  be 
detected  in  the  wash-water  by  means  of  the  biuret  test.  The  ques- 
tion as  to  the  possibility  of  the  formation  of  traces  of  albumoses 
from  other  proteids  during  this  treatment  under  certain  circum- 
stances has  not  been  closely  investigated  as  yet. 

If  a  solution  saturated  with  ammonium  sulphate  is  to  be  tested 
by  the  biuret  test,  it  must  first  be  treated  with  a  slight  excess  of 
concentrated  caustic-soda  solution,  keeping  the  solution  cold,  and 
after  the  sodium  sulphate  has  settled  the  liquid  is  treated  with  a 
2^  solution  of  copper  sulphate,  drop  by  drop. 

The  biuret  test  (colorimetric)  and  the  polariscopic  method  have 
been  used  in  the  quantitative  estimation  of  albumoses  and  peptones. 
These  methods  do  not  yield  exact  results. 

Coagulated  Proteids. — Proteids  may  be  converted  into  the 
coagulated  condition  by  different  means:  by  heating  (see  page  25), 
by  the  action  of  alcohol,  especially  in  the  presence  of  neutral  salts, 
and  in  certain  cases,  as  in  the  conversion  of  fibrinogen  into  fibrin 
(Chapter  YI),  by  the  action  of  an  enzyme.     Ramsdex  ''  has  shown 

'Zeitschr.  f.  physiol.  Chem. ,  Bd.  15. 
*Du  Bois-Reymond's  Arch.,  1894. 


42  THE  PROTEIN  SUBSTANCES. 

that  a  proteid  solution  may  also  be  coagulated  by  continuous  shak- 
ing, and  indeed  in  a  few  cases  (ovalbumin)  it  may  be  completely 
coagulated.  This  coagulation  is,  however,  not  identical  with  heat 
coagulation.  The  nature  of  the  processes  which  take  place  during 
coagulation  is  unknown.  The  coagulated  albuminous  bodies  are 
insoluble  in  water,  in  neutral  salt  solutions,  and  in  dilute  acids  or 
alkalies,  at  normal  temperature.  They  are  dissolved  and  converted 
into  albuminates  by  the  action  of  less  dilute  acids  or  alkalies, 
especially  on  heating. 

Coagulated  proteids  appear  also  to  occur  in  animal  tissues.  We 
find,  at  least  in  many  organs  such  as  the  liver  and  other  glands, 
proteids  which  are  not  soluble  in  water,  dilute  salt  solutions,  or  very 
dilute  alkalies,  and  only  dissolve  after  being  modified  by  strong 
alkalies. 

Appendix. 

Vegetable  Proteids.  Vegetable  proteids  seem  to  have  the  same 
essential  properties  as  the  animal  proteids,  and  the  three  chief 
groups  of  native  proteids  occur  in  the  plants  as  well  as  the  animal 
organism.  We  recognize  the  following  as  vegetable  proteids: 
albumins,  globulins  (phytovitellin,  vegetable  myosin,  paraglobulin), 
and  nucleoalhimins  (pea  legumin).  Besides  these  a  special  group 
of  coagulated  proteids,  so-called  gluten  proteins,  occur,  which  are 
partly  soluble  in  alcohol.  It  seems  that  too  much  importance  is 
given  to  the  solubilities  of  the  vegetable  proteids,  and  more  exhaus- 
tive investigations  seem  to  be  necessary.' 

Poisonous  Proteids.  Attention  was  called  in  the  first  chapter 
to  the  fact  that  high  plants  and  animals,  as  well  as  microbes,  can 
produce  proteids  having  specific,  sometimes  intense,  poisonous 
action. 

We  know  very  little  positively  in  regard  to  the  nature  of  these 
proteids.  Those  which  have  been  isolated  belong  to  certain  of  the 
proteid  groups — some  are  albumins,  others  globulins  or  compound 
proteids,  and  the  majority  seem  to  be  albumoses — still  little  is 
known  in  regard  to  their  chemical  nature.  From  a  chemical  stand- 
point we  do  not  differentiate  between  a  poisonous  and  a  harmless  pro- 
teid ;  for  example,  between  a  poisonous  and  a  non-poisonous  globu- 

1  See  Kjeldahl :  Undersogelser  over  de  optiske  Forhold  hos  nogle  Plante- 
seggehvidestoffer.  Forhandlingerne  ved  de  skandinaviske  Naturforskeres  14. 
Mode.     KiobenbavDj  1892. 


COMPOUND  PROTEIDS.  43 

lin.  The  fundamental  question  whether  those  that  have  been  iso- 
lated as  poisonous  proteids  are  really  poisonous  or  not,  or  whether 
they  consist  of  a  harmless  proteid  contaminated  with  a  poisonous 
substance,  cannot  be  considered  as  settled. 

One  thing  is  certain,  and  that  is  that  one  and  the  same  tox- 
albumin  can  show  essentially  different  chemical  properties  under 
different  circumstances,  although  it  shows  the  same  specific  action. 
Tuberculin  is  an  example  of  this  kind.  This,  according  to  most 
investigators,  is  an  albumose ;  but  contrary  to  this  Helman  '  has 
isolated  a  tuberculin  which  does  not  act  like  an  albumose  and  on 
the  whole  only  gives  faint  proteid  reactions.  The  elementary  com- 
position of  one  and  the  same  toxalbumin,  prepared  in  different 
ways,  also  shows  considerable  variations.'' 

Under  such  circumstances,  nothing  definite  can  be  stated  in 
regard  to  the  properties  of  the  different  toxalbumins.  The  study 
of  the  nature  of  poisonous  proteids  seems  to  be  in  the  same  state  as 
the  study  of  the  enzymes,  and  we  cannot  deny  that  in  many  cases 
an  unmistakable  similarity  of  action  is  observed  between  toxalbu- 
mins and  enzymes. 

II.  Compound  Proteids. 

With  this  name  we  designate  a  class  of  bodies  which  are  more 
complex  than  the  simple  proteids  and  which  yield  as  nearest  split- 
ting products  simple  proteids  on  one  side  and  non-proteid  bodies, 
such  as  coloring  matters,  carbohydrates,  xanthin  bases,  etc.,  on  the 
other.  * 

The  compound  proteids  known  at  the  present  time  are  divided 
into  three  chief  groups.  These  groups  are  the  hcBmoglobins,  the 
glycoproteids,  and  the  nucleoproteicls.  The  haemoglobins  will  be 
treated  of  in  a  following  chapter  (Chapter  VI,  on  the  blood). 

Glycoproteids  are  those  compound  proteids  which  on  decomposi- 
tion yield  a  proteid  on  one  side  and  a  carbohydrate  or  derivatives 
of  the  same  on  the  other.     Some  glycoproteids- are  free  from  phos- 

'  Archives  de  sciences  biologiques  de  St.  Petersboiirg.     Tome  1,  1892. 

-See  S  Dzierzgowski  and  L.  de  Rekowslii  :  Recherclies  sur  la  transforma- 
tion des  milieux  nutritifs  par  les  bacilles  de  la  diplitberie,  etc.  Archives  de 
sciences  biologiques  de  St.  Petersbourg.     Tome  1 ,  1892. 

*  Hoppe-Seyler  has  given  the  name  prote'ide  to  these  compound  proteids,  but 
as  this  term  is  misleading  in  English  we  do  not  use  it  in  English  classifications 
in  this  sense. 


4i  THE  PROTEIN  SUBSTANCES. 

phorus  (macins,  mucinoids,  and  hyalogens),  and  some  contain 
phosphorus  (phosphoglycoproteids) . 

Mucin  Substances.  We  designate  as  mucins  colloid  substances 
whose  solutions  are  mucilaginous  and  thready,  and  which  when 
treated  with  acetic  acid  give  a  precipitate  insoluble  in  an  excess  of 
acid,  and  on  boiling  with  dilute  mineral  acids  yield  a  substance 
capable  of  reducing  copper  oxyhydrate.  This  last-mentioned  fact, 
which  was  first  observed  by  Eichwald,'  differentiates  mucins  from 
other  bodies  which  have  long  been  mistaken  for  it  and  which  have 
similar  physical  properties.  On  the  other  hand,  bodies  whose 
physical  properties  differ  from  it,  but  which  give  a  reducible  sub- 
stance on  boiling  with  dilute  mineral  acids,  have  also  been  designated 
as  mucins. 

The  different  bodies  characterized  as  mucin  substances  corre- 
spond, first,  either  to  true  mucins,  or,  second,  to  ?nucoids  or 
muci7ioids. 

All  mucin  substances  contain  carion,  hydrogen,  nitrogen, 
sulphur,  and  oxygen.  Compared  with  albuminous  bodies  they  con- 
tain less  nitrogen  and,  as  a  rule,  considerably  less  carbon.  As 
immediate  decomposition  products  they  yield  albuminous  bodies  on 
one  side  and  carbohydrates  or  acids  allied  thereto  on  the  other. 
On  boiling  with  dilute  mineral  acids  they  all  give  a  reducing  sub- 
stance. 

The  true  mucins  are  characterized  by  their  natural  solution,  or 
one  prepared  by  the  aid  of  a  trace  of  alkali,  being  mucilaginous, 
thread-like,  and  giving  a  precipitate  with  acetic  acid  which  is  in- 
soluble in  excess  of  acid.  The  7nucoids  do  not  show  these  physical 
properties  and  have  other  solubilities  and  precipitation  properties. 
As  we  have  intermediate  steps  between  different  albuminous  bodies, 
so  also  we  have  such  between  true  mucins  and  mucoids,  and  a 
sharp  line  between  these  two  groups  cannot  be  drawn. 

True  mucins  are  secreted  by  the  larger  mucous  glands,  by  cer- 
tain mucous  membranes,  also  by  the  skin  of  snails  and  other 
animals.  True  mucin  also  occurs  in  the  connective  tissue  and 
navel-cord.  Sometimes,  as  in  snails  and  in  the  membrane  of  the 
frog-egg  (GiACOSA "),  a  mother-substance  of  mucin,  a  mucinogen, 
has  been  found  which  may  be  converted  into  mucin  by  alkalies. 

•  Annal.  d.  Cliem.  u.  Pharm.,  Bd.  134. 

^Zeitsclir.  f.  physiol.  Chem.,  Bd.  7;  also  Hammarsten,  Pfliiger's  Archiv, 
Bd.  36. 


TRUE  MUCINS.  45 

Mucoid    substances  are  found  in   cartilage,   certain   cysts,   in  the 

cornea,  the  crystalline  lens,   white  of  egg,  and  in  certain  ascitic 

fluids.     As  the  mucin  question  has  been  very  little  studied,  it  is  at 

the  present  time  impossible  to  give  any  positive  statements  in  regard 

to  the  occurrence  of   mucins  and  mucoids,  especially  as  without 

doubt  in  many  cases  non-mucinous  substances  have  been  described 

as  mucins.     So  much  is  sure,  that  mucins  or  nearly  related  bodies 

occur  widely  diffused  in  the  organism  in  certain   tissues.     From 

their  decomposition  products  we  derive  a  great  deal  of  knowledge 

in  regard  to  the  formation  and  splitting  of  carbohydrates  or  kindred 

bodies  (glycuronic  acid)  from  other  complex  groups. 

True  Mucins.     Thus  far  we  have  been  able  to  obtain  only  a  few 

mucins  in  a  pure  and  unchanged  condition  due  to  the  reagents  used. 

The  elementary  analyses  of  these  mucins  have  given  the  following 

results: 

C  H         N         S  0 

Mucin  from  snail 50.33  6.84  13.65  1.75  27.44  (Hammaksten)  ' 

Mucin  from  tendon 48.30  6.44  11.75  0.81  32.70  (Loebisch)  « 

Mucin  from  submaxillary. . .    48.84  6.80  12.32  0.84  31.20  (Hammausten)* 

The  mucin  of  the  snail-skin,  which  stands  closest  to  keratin, 
contains  more  sulphur  than  the  other  mucins.  The  sulphur  is 
moreover,  at  least  in  certain  mucins,  part  in  loose  and  part  in  strong 
chemical  union. 

By  the  action  of  superheated  steam  on  mucin  a  carbohydrate, 
animal  gum  (Lakdwehr  *),  is  split  off.  This  is  not  essentially  true 
for  all  mucins,  as  the  mucin  from  the  submaxillary  gland  yields  a 
gummy  substance  containing  nitrogen.* 

On  boiling  mucin  with  dilute  mineral  acids,  acid  albuminate 
and  bodies  similar  to  albumose  or  peptone  are  obtained,  besides 
a  reducing  substance  which  has  not  been  closely  studied.  By  the 
action  of  stronger  acids  we  obtain  among  other  bodies  leucin,  tyro- 
sin,  and  levulinic  acid  (Lan'dwehr).  Certain  mucins,  as  the  sub- 
maxillary mucin,  are  easily  changed  by  very  dilute  alkalies,  as 
lime-water,  while  others,  such  as  tendon-mucin,  are  not  affected 
(LoEBiscH*).     If  a  strong  caustic-alkali  solution,  as  a  5^  KOH 

'  Pfliiger's  Arcliiv,  Bd.  36. 
'Zeitschr.  f.  pbysiol.  Cliem.,  Bd.  10. 
sZeitschr.  f.  pbysiol.  Cbem.,  Bd.  12. 

■•Zeitscbr.  f.  pbysiol.  Cbem.,  Bdd.  8  and  9  ;  also  Pfliiger's  Archiv,  Bdd.  39 
and  40. 

^  Not  oflScially  published  by  tbe  author. 
•Zeitscbr.  f.  pbysiol.  Cbem.,  Bd.  10. 


46  THE  PROTEIN  SUBSTANCES. 

solution,  is  allowed  to  act  on  submaxillary  mucin,  we  obtain  alkali 
albuminate,  a  body  similar  to  albumose  and  peptone,  and  one  or 
more  substances  of  an  acid  reaction  and  with  strong  reducing 
powers. 

In  one  or  the  other  respect  the  different  mucins  act  somewhat 
differently.  For  example,  the  snail  and  tendon  mucins  are  insolu- 
ble in  dilute  hydrochloric  acid  of  1-2  p.  m.,  while  the  mucin  of  the 
submaxillary  gland  and  the  naval-cord  are  soluble.  Tendon-mucin 
becomes  flaky  with  acetic  acid,  while  the  other  mucins  are  precipi- 
tated in  more  or  less  fibrous,  tough  masses.  Still  all  the  mucins 
have  certain  reactions  in  common. 

In  the  dry  state  mucin  forms  a  white  or  yellowish-gray  powder. 
"When  moist  it  forms,  on  the  contrary,  flakes  or  yellowish-white 
tough  lumps  or  masses.  The  mucins  are  acid  in  reaction.  They 
give  the  color  reactions  of  the  albuminous  bodies.  They  are  not 
soluble  in  water,  but  may  give  a  neutral  solution  with  water  and  the 
smallest  quantity  of  alkali.  Such  a  solution  does  not  coagulate  on 
boiling,  while  acetic  acid  gives  at  the  normal  temperature  a  precipi- 
tate which  is  insoluble  in  an  excess  of  the  precipitant.  If  5-10^ 
NaCl  be  added  to  a  mucin  solation,  this  can  now  be  carefully 
acidified  with  acetic  acid  without  giving  a  precipitate.  Such 
acidified  solutions  are  copiously  precipitated  by  tannic  acid;  with 
potassium  ferrocyanide  they  give  no  precipitate,  but  on  sufficient 
concentration  they  become  thick  or  viscous.  A  neutral  solution  of 
mucin-alkali  is  precipitated  by  alcohol  in  the  presence  of  neutral 
salts;  it  is  also  precipitated  by  several  metallic  salts.  If  mucin  is 
heated  on  the  water-bath  with  dilute  hydrochloric  acid  of  about  3^, 
the  liquid  gradually  becomes  a  yellowish  or  dark  brown  and  re- 
duces copper  oxyhydrate  from  alkaline  solutions. 

The  mucin  most  readily  obtained  in  large  quantities  is  the  sub- 
maxillary mucin,  which  may  be  prepared  in  the  following  way: 
The  filtered  watery  extract  of  the  gland,  free  from  form-elements 
and  as  colorless  as  possible,  is  treated  with  25^  hydrochloric  acid, 
so  that  the  liquid  contains  1.5  p.  m.  HCl.  On  the  addition  of  the 
acid  the  mucin  is  immediately  precipitated,  but  dissolves  on  stirring. 
If  this  acid  liquid  is  immediately  diluted  with  2-3  vols,  of  water, 
the  mucin  separates  and  may  be  purified  by  redissolving  in  1-5 
p.  m.  acid,  and  diluting  with  water  and  washing  therewith.  The 
mucin  of  the  naval-cord  may  be  prepared  in  the  same  way. '     The 

'  The  author  has  not  been  able  to  obtain  this  pure,  so  the  analysis  has  not 
been  given  in  the  previous  table  of  the  mucins. 


MUCOIDS.  4T 

tendon-mncin  is  prepared  from  tendons  which  have  first  been  freed 
from  proteid  by  common-salt  solution  and  water.  They  are  ex- 
tracted with  lime-water,  the  filtrate  is  precipitated  with  acetic  acid, 
and  the  precipitate  purified  by  redissolving  in  dilute  alkali  or  lime- 
water,  precipitating  with  acid,  and  washing  with  water  (Rollett,' 
Loebisch).     Lastly,  the  mucins  are  treated  with  alcohol  and  ether. 

Mucoids  or  Mucinoids.  To  this  grouj^  belong  pseudomucin, 
which  occurs  in  ovarial  liquids,  colloid,  which  is  probably  related 
thereto,  and  cliondromucoid,  which  occurs  in  cartilage,  and  others. 
These  bodies  will  be  treated  of  later  in  their  respective  chapters. 

Hyalogens.  Under  this  name  Krukenberg  '  has  designated  a  number  of 
differing  bodies,  which  are  characterized  by  the  following  :  By  the  action  of 
alkalies  they  change,  with  the  splitting  off  of  sulphur  and  some  nitrogen,  into 
soluble  nitrogenized  products  called  by  him  hyalines  and  which  yield  a  pure 
carbohydrate  by  further  decomposition.  We  find  that  very  heterogeneous 
substances  are  included  in  these  groups.  Certain  of  these  hyalogens  seem  un- 
doubtedly to  be  glycoproteids.  Neossin^  of  the  Chinese  edible  swallow"s-nest, 
memhranin'^  of  Descemet's  membrane  and  of  the  capsule  of  the  crys- 
talline lens,  and  spirographin^  of  the  skeletal  tissue  of  the  worm  Spiro- 
graphis  seem  to  act  as  such.  Others  on  the  contrary,  such  as  hyalin^  oi 
the  walls  of  hydatid  cysts,  onuphin''  from  the  tubes  of  Onuphis  tubicola,  seem 
not  to  be  compound  proteids.  The  so-called  mucin  of  the  holoihures,^  and 
chondrosin^  of  the  sponge,  Chondrosia  reniformis,  and  others  may  also  be 
classed  with  the  hyalogens.  As  the  various  bodies  designated  by  Kruken- 
berg as  hyalogens  are  very  dissimilar,  it  is  not  of  much  importance  to  arrange 
these  in  special  groups. 

Phosphoglycoproteids.  This  group  includes  the  phosphorized  glycoproteids. 
These  compound  proteids  are  decomposed  by  pepsin  digestion  and  split  off 
para-  or  pseudonuclein,  similar  to  nucleoalbumins.  They  differ  from  the 
nucleoalbumins  in  that  they  yield  a  reducing  substance  on  boiling  with  acids, 
and  from  the  nucleoproteids  in  that  they  do  not  yield  xanthin  bases. 

Only  two  phosphorized  glycoproteids  are  known  at  the  present  time,  namely, 
ichihulin,  occurring  in  carp  eggs  and  studied  by  Walter  '"  and  which  were 
considered  as  vitellin  for  a  time.  Ichthulin  has  the  following  composition  .  C' 
53.53  ;  H  7.71  ;  N  15.64  ;  S  0.41  ;  P  0.43  ;  Fe  0.10^.  In  regard  to  solubilities 
it  is  similar  to  a  globulin.  Walter  has  prepared  a  reducing  substance  from 
the  paranuclein  of  ichthulin  which  gave  a  very  crystalline  combination  with 
phenylhydrazin . 

Another  phosphoglycoproteid  is  helicoproteid,  obtained  by  the  author"  from 

'  Wien.  Sitzungsber.,  Bd.  39,  Abth.  2. 

''Verh.  d.  physik.-med.  Gesellsch.  zu  Wiirzburg,  1883;  also  Zeitschr.  f. 
Biologie,  Bd.  33. 

"Krukenberg,  Zeitschr.  f.  Biologie.  Bd.  33. 

*C.  Th.  Morner,  Zeitschr.  f.  physiol.  Chem.,  Bd.  18. 

'Krukenberg,  Wiirzburg,  Verhandl.  1883  ;  also  Zeitschr.  f.  Biologie.  Bd.  38. 

*A.  Liicke,  Arch.  f.  path  Anat.,  Bd.  19;  also  Krukenberg,  Vergleichende 
physiol.  Stud.,  Series  1  and  3,  1881. 

'  Schmiedeberg,  Mitth.  aus  d.  zool.  Stat,  zu  Neapel,  Bd.  3,  1882. 

'Hilger,  Pfliiger's  Archiv,  Bd.  3. 

'  Krukenberg,  Zeitschr.  f .  Biologie,  Bd.  32. 

"Zeitschr.  f.  physiol.  Chem.,  Bd.  15. 

«'  Pfliiger's  Archiv,  Bd.  36. 


48  TEE  PROTEIN  SUBSTANCES. 

tlie  glands  of  the  snail  Helix  pomatia.  It  has  the  following  conaposition  : 
C  46.99  ;  H  6.78  ;  N  6.08  ;  S  0.62  ;  P  0.475^.  It  is  converted  into  a  gummy, 
laevorotatory  carbohydrate,  called  animal  sinistrin,  by  the  action  of  alkalies. 
On  boiling  with  an  acid  it  yields  a  dextrorotatory,  reducible  substance. 

Nucleoproteids.  With  this  name  we  designate  those  compound 
proteids  which  yield  true  nncleins  (see  Chapter  V)  on  pej)sin  diges- 
tion and  those  which  yield,  besides  proteids,  xanthin  bases  or 
so-called  nnclein  bases  on  boiling  Avith  dilate  mineral  acids. 

The  nucleoproteids  seem  to  be  widely  diliased  in  the  animal 
body.  They  occur  chiefly  in  the  cell  nuclei,  but  they  also  often 
occur  in  the  protoplasm.  They  may  also  pass  into  the  animal  fluids 
on  the  destruction  of  the  cells,  hence  nucleoproteids  have  also  been 
found  in  blood  serum. 

They  may  be  considered  as  combinations  of  a  proteid  nucleus 
with  a  side  chain,  which  Kossel  '  calls  the  prostetic  group. 
This  side  chain,  which  contains  the  phosphorus,  yields  on  the 
decomposition  of  certain  nucleoproteids,  such  as  from  the  yeast 
cell, \  or  from  the  pancreas,'  besides  nuclein  bases  also  reducing 
substances,  which  form  crystalline  combinations  with  phenyl- 
hydrazin.  It  is  still  an  open  question  as  to  the  formation  of 
reducing  substances  from  other  nucleoproteids.  This  prostetic 
group  may  be  split  off  as  nucleic  acid  (see  Chapter  V)  by  the  action 
of  alkalies.  The  nucleoproteids  seem  to  be  dissimilar  according  to 
the  kind  of  nucleic  acid  split  off  because  they  yield  differing  relative 
amounts  of  the  various  xanthin  bases. 

The  nucleoproteids  are  acids  whose  alkali  compounds  are  solu- 
ble in  water  and  which  coagulate  on  heating  (this  is  true  at  least 
for  all  genuine  nucleoproteids  investigated  up  to  the  present  time). 
They  may  be  precipitated  from  their  alkali  compounds  by  acetic 
acid,  and  the  precipitate  is  more  or  less  soluble  in  an  excess  of  the 
acid.  A  confusion  may  occur  here  with  nucleoalbumins  and  also 
with  mucin  substances.  This  confusion  can  be  avoided  by  warming 
the  body  for  some  time  on  the  water-bath  with  dilute  sulphuric 
acid,  and  on  cooling  filtering  and  saturating  the  filtrate  with 
ammonia  and  testing  for  xanthin  bodies  by  an  ammoniacal  solution 
of  silver  nitrate.  Any  precipitate  formed  is  examined  more  closely 
by  the  methods  as  given  in  Chapter  V. 

'  Verb.  d.  physiol.  Gesellsch.  zu  Berlin,  1893-93,  No.  1. 

'  A,  Kossel,  Du  Bois-Reymond's  Archiv,  Physiol   Abth.,  189L 

»  O.  Hammarsten,  Zeitschr.  f,  physiol.  Chem.,  Bd.  19. 


KERATINS.  49 

The  properties  of  the  various  nucleoproteids  are  given  more 
in  detail  in  the  various  chapters  which  follow. 

III.  Albuinoids  or  Albuminoids. 

Under  this  name  we  collect  into  a  special  group  all  those  protein 
bodies  which  cannot  be  placed  in  either  of  the  other  two  groups, 
although  they  differ  essentially  among  themselves  and  from  a 
chemical  standpoint  do  not  show  any  radical  difference  from  the 
true  proteid  bodies.  The  most  important  and  abundant  of  the 
bodies  belonging  to  this  group  are  important  constituents  of  the 
animal  skeleton  or  the  cutaneous  structure.  They  occur  as  a  rule 
in  an  insoluble  state  in  the  organism,  and  they  are  distinguished  iu 
most  cases  by  a  pronounced  resistance  to  reagents  which  dissolve 
proteids  or  to  chemical  reagents  in  general.. 

The  Keratin  Group.  Keratin  is  the  chief  constituent  of  the 
horny  structure,  of  the  epidermis,  of  hair,  wool,  of  the  nails,  hoofs, 
horns,  feathers,  of  tortoise-shell,  etc.,  etc.  Keratin  is  also  found 
as  neurokeratin  (Kuhiste')  in  the  brain  and  nerves.  The  shell- 
membrane  of  the  hen's  egg  seems  also  to  consist  of  keratin. 

It  seems  that  there  exist  more  than  one  keratin,  and  these  form 
a  special  group  of  bodies.  This  fact,  together  with  the  difficulty 
in  isolating  the  keratin  from  the  tissues  in  a  pure  condition  without 
a  partial  decomposition,  is  sufficient  explanation  for  the  variation  in 
the'  elementary  composition  given  below.  As  examples  the  analyses 
of  a  few  tissues  rich  in  keratin  and  of  keratins  are  given  as  follows: 


C 

H 

N 

S 

0 

Human  hair .... 

50. 05 

6.36 

17.14 

5.00 

20.85 

(V   Laer)2 

Nail 

51.00 

6.94 

17.51 

2.80 

21.75 

(MulderH 

Neurokeratin. 

.56.11-58.45 

r.  26-8. 02 

11.46-14.32 

1.63-2.24 

(KUHNE)l 

Horn  (average  1. 

50.86 

6.94 

3.30 

(HORBACZEWSKl)* 

Tortoise-shell... 

54.89 

6.56 

\^.V 

2.22 

19.56 

(Muldek)3 

Shell-membrane 

49.78 

6.64 

16.43 

4.25 

22.90 

(Lindvall)* 

MoHR '  has  determined  the  quantity  of  sulphur  in  various 
keratin  substances.  The  percentage  varies  from  2.6  to  5.3.  Sul- 
phur is  at  least  in  part  in  loose  combination,   and   it  is   partly 

'  Kilhne   and   Ewald,    Verb    d   natiirliistor.-med.   Vereins   zu    Heidelberg- 
(N.  F.),  Bd.  1  ;  also  Kuline  and  Chittenden,  Zeitschr.  f.  Biologic,  Bd.  26. 
'  Annal.  d.  Cbem   u.  Pharm.,  Bd.  45. 
3  Versuch  einer  allgem.  physiol   Chem.     Braunschweig,  1844-51. 

*  See  Drechsel  in  Ladenburg's  Handworterbuch  d.  Chem.,  Bd.  3. 

*  See  Maly'.s  Jabresbericht,  1881. 

«  Zeitschr.  f,  pbysiol.  Chem.,  Bd.  20. 


60  THE  PROTEIN  SUBSTANCES. 

removed  by  the  action  of  alkalies  (as  sulphides),  or  indeed  in  part 
by  boiling  with  water.  Combs  of  lead  after  long  usage  become 
black,  and  this  is  due  to  the  action  of  the  sulphur  of  the  hair.  On 
heating  keratin  with  water  in  sealed  tubes  at  a  temperature  of  150° 
to  200"  C.  it  dissolves,  with  the  elimination  of  sulphuretted 
hydrogen,  forming  a  non-gelatinizing  liquid  which  contains  albu- 
mose  (called  heratinose  by  Keitkenbeeg  ')  and  peptone  (?).  Kera- 
tin is  dissolved  by  alkalies,  especially  on  heating,  forming,  besides 
alkali  sulphides,  albumoses  and  peptones  (?). 

The  decomposition  products  of  keratins  are  moreover  the  same 
as  the  true  proteids.  On  boiling  with  acids  we  obtain  besides  leucin 
and  tyrosin,  which  occurs  in  relatively  great  amounts  (1-5^), 
asparaginic  acid''  and  glutamic  acid,^  ammonia,  and  sulphuretted 
hydrogen.  Hedust*  has  obtained  a  little  lysin  and  considerable 
lysatinin  from  horn  shavings.  Besides  these  he  obtained  a  sulphur 
compound  whose  hydrochloric-acid  combination  had  the  composi- 
tion Cj^HgglSr^Oj^SCl^,  and  another  body  which  is  perhaps  identical 
with  serin.  There  is  no  doubt  that  the  keratins  are  derived  from 
the  proteids.  Deechsel  '  is  also  of  the  opinion  that  in  the  keratin 
a  part  of  the  oxygen  of  the  proteids  is  exchanged  for  sulphur,  and 
a  part  of  the  leucin,  or  any  other  amido-acid,  is  exchanged  for 
tyrosin.  Keratin  and  proteids  give  the  same  decomposition  products, 
with  the  exception  that  the  former  gives  proportionally  a  greater 
quantity  of  tyrosin  {\-6'/o).  Among  the  sulphurized  cleavage 
products  of  keratin  Emmeeling  °  found  cystin,  and  Sutee  '  thio- 
Indic  acid.  Sutee  could  not  detect  either  cystin  or  cystein. 
Among  the  cleavage  products  obtained  by  the  action  of  hydrochloric 
acid  and  tin  chloride  Hediist  *  obtained  a  base  which  is  probably 
identical  with  the  base  arginin,  QJl^Jsfi^,  isolated  by  Schulze 
and  Steiger  °  from  lupin  and  malt  acrospire. 

'  Untersuch.  liber  d,  chem.  Bau  d.  EiweisskOrper.  Sitzungsber.  d. 
Jenaischen  Gesellscb.  f.  Med.  u.  Naturwissenscli.,  1886. 

^  Kreusler,  Journ.  f.  prakt.  Chem.,  Bd.  107. 

^  Horbaczewski,  Sitzungsber.  d.  k.  k.  Wien.  Akad.  d.  Wissenscb.,  Bd.  80. 

•*  Kgl.  fysiogr.  Sallsk.  i  Lund  handlingar,  Bd.  4  ;  also  Maly's  Jaliresber., 
:Bd.  23. 

*  Drecbsel  in  Ladenburg's  Handworterbucb  d.  Chem.,  Bd.  3. 

«  Chemiker-Zeitung,  No.  80,  1894. 

•»  Zeitschr.  f.  physiol.  Chem.,  Bd.  20. 

«  Ihid.,  Bd.  20. 

«  Ihid.,  Bd.  11,  S.  43. 


ELAsrm.  51 

Bodies  occur  in  the  animal  kingdom  which  form  intermediate 
bodies  between  coagulated  albumin  and  keratin.  C.  Th.  Morxer  ' 
has  detected  such  a  body  in  the  tracheal  cartilage,  which  forms  a 
net-like  basement  membrane.  This  substance  appears  to  be  related 
to  keratin  on  account  of  its  solubilities  and  on  the  quantity  of  the 
sulphur  (which  turns  lead  black)  it  contains,  while  according  to  its 
solubility  in  gastric  juice  it  must  stand  close  to  the  proteids. 
Another  substance,  more  similar  to  keratin,  forms  the  horny  layer 
in  the  gizzard  of  birds.  According  to  J.  Hedenius  "^  this  substance 
is  insoluble  in  gastric  or  pancreatic  juice  and  acts  quite  similar  to 
keratin.  It  contains  only  Ifo  sulphur,  and  yields  on  decomposition 
only  very  little  tyrosin  besides  considerable  leucin. 

Keratin  is  amorphous  or  takes  the  form  of  the  tissues  from 
which  it  was  prepared.  On  heating  it  decomposes  and  generates 
an  odor  of  burnt  horn.  It  is  insoluble  in  water,  alcohol,  or  ether. 
On  heating  with  water  to  150°-200°  C.  it  dissolves.  It  also  dis- 
solves gradually  in  caustic  alkalies,  especially  on  heating.  It  is  not 
dissolved  by  artificial  gastric  juice  or  by  trypsin  solutions.  Keratin 
gives  the  xanthoproteic  reaction,  as  well  as  the  reaction  with 
Millon's  reagent,  even  though  they  are  not  always  typical. 

In  the  preparation  of  keratin  a  finely  divided  horny  structure  is 
treated  first  with  boiling  water,  then  consecutively  with  diluted 
acid,  pepsin-hydrochloric  acid,  and  alkaline  trypsin  solution,  and, 
lastly,  with  water,  alcohol,  and  ether. 

Elastin  occurs  in  the  connective  tissue  of  higher  animals,  some- 
times in  such  large  quantities  that  it  forms  a  special  tissue.  It 
occurs  most  abundantly  in  the  cervical  ligament  (ligamentum 
nuchas). 

Elastin  is  generally  considered  as  a  sulphur-free  substance. 
According  to  the  investigations  of  CniTTENDEisr  and  Hart,^  it  is  a 
question  whether  or  not  elastin  does  not  contain  sulphur,  which  is 
removed  by  the  action  of  the  alkali  in  its  preparation.  H.  Schwarz* 
has  been  able  to  ^Drepare  an  elastin  containing  sulphur  from  the 
aorta  by  another  method,  and  this  sulphur  can  be  removed  by  the 
action  of  alkalies,  without  changing  the  properties  of  the  elastin. 
Elastin  is  hence  perhaps  a  protein  substance  containing  sulphur 
which  exists  only  loosely  combined.    The  most  trustworthy  analyses 

'  Maly's  Jaliresber.,  Bd.  18. 

2  Skandinav.  Arch.  f.  Physiol.,  Bd.  3. 

3  Zeitschr.  f.  Biologic,  Bd.  25. 

*  Zeitschr.  f .  physiol.  Chem. ,  Bd.  18. 


52  THE  PROTEIX  SUBSTANCES. 

of  elastin  from  the  cervical  ligament  (Nos.  1  and  2)  and  from  the 
aorta  (No.  3)  have  given  the  following  results : 


C 

H 

N 

S 

o 

1. 

2. 
3. 

54.33 

54  24 
53.95 

6.99 

7.27 
7.03 

16.75 

16.70 
16.67 

0.38 

21.94 
21.79 

(HORBACZEWSKI)' 

(Chittenden  and  Hast)' 

(H.   SCHWARZ)=' 

The  splitting  products  of  elastin  are  the  same  as  for  the  true 
proteids  with  the  difference  that  glycocoll  but  no  aspartic  and 
glutamic  acids  are  obtained.*  Tyrosin  is  only  obtained  in  small 
quantities.  Schwarz  was  able  to  detect  lysatinin  in  the  decom- 
position products,  but  not  lysin  positively.  On  putrefaction "  no^ 
iudol  or  phenol  is  obtained,  but  Schwaez,  on  the  contrary,  obtained 
indol,  skatol,  benzol,  and  phenols,  but  no  methylmercaptan,  on 
fusing  aorta-elastin  with  caustic  potash.  On  heating  with  water  in 
closed  vessels,  on  boiling  with  dilute  acids,  or  by  the  action  of 
proteolytic  enzymes,  the  elastin  dissolves  and  splits  into  two  chief 
products,  called  by  Horbaczewski  Jiemielastin  and  elastinpeptone. 
According  to  CHiTTEKDEisr  and  Hart,  these  products  correspond 
to  two  albumoses  designated  by  them  protoelastose  and  deutero- 
elastose.  The  first  is  soluble  in  cold  water  and  separates  on  heat- 
ing, and  its  solution  is  precipitated  by  mineral  acid  as  well  as  by 
acetic  acid  and  potassium  ferrocyanide.  The  watery  solution  of 
the  other  does  not  become  cloudy  on  heating,  and  is  not  precipi- 
tated by  the  above-mentioned  reagents. 

Pure  dry  elastin  is  a  yellowish-white  powder ;  in  the  moist  state 
it  appears  like  yellowish-white  threads  or  membranes.  It  is  insolu- 
ble in  water,  alcohol,  or  ether,  and  shows  a  resistance  against  the 
action  of  chemical  reagents.  It  is  not  dissolved  by  strong  caustic 
alkalies  at  the  ordinary  temperature,  and  only  slowly  at  the  boiling 
temperature.  It  is  very  slowly  attacked  by  cold  concentrated 
sulphuric  acid,  and  it  is  relatively  easily  dissolved  on  warming  with 
strong  nitric  acid.  Elastins  of  differing  origins  act  differently  with 
cold  concentrated  hydrochloric  acid;  for  instance,  elastin  from  the 
aorta  dissolves  readily  therein,  while  elastin  from  the  ligamentum 
nucha},  at  least  from  old  animals,  dissolves  with  difficulty.    Elastin 

'  Zeitschr.  f.  physiol.  Chem.,  Bd.  6. 

2  Zeitsclir.  f.  Biologie,  Bd.  25. 

3  Zeitschr.  f,  physiol.  Chem.,  Bd.  18. 

^  See  Drechsel  in  Ladenburg's  Handworterbuch  d.  Chem.,  Bd.  3,  and  Hor- 
baczewski, Monatshefte  f.  Chem.,  Bd.  6. 
*  Walchli,  Journ.  f.  prakt.  Chem.,  Bd.  17. 


COLLAGEN.  53 

is  more  readily  dissolved  by  warm  concentrated  hydrochloric  acid. 
It  responds  to  the  xanthoproteic  reaction  and  with  Millox's 
reagent. 

On  account  of  its  great  resistance  to  chemical  reagents,  elastin 
may  be  prepared  (best  from  the  ligamentuni  nucha?)  in  tiie  follow- 
ing way:  First  boil  with  water,  then  with  1^  caustic  potash,  then 
again  with  water,  and  lastly  with  acetic  acid.  The  residue  is 
treated  with  cold  5^  hydrochloric  acid  for  twenty-four  hours,  care- 
fully washed  with  water,  boiled  again  with  water,  and  then  treated 
with  alcohol  and  ether. 

ScHWATZ  first  incompletely  digested  the  tissues  with  pepsin, 
washed  first  with  soda  solution  and  then  with  water,  and  boiled 
lastly  with  water  nntil  the  elastic  substance  was  dissolved  away. 
The  dried  and  powdered  substance  is  again  digested  with  gastric 
juice  and  treated  as  above,  and  then  boiled  with  water  until  the 
contaminating  reticulin-like  substance  is  completely  removed. 

Collagen,  or  gelatine-forming  substance,  occurs  very  extensively 
in  the  animal  kingdom.  The  flesh  of  cephalopods  is  claimed  to 
contain  collagen.'  Collagen  is  the  chief  constituent  of  the  fibrils 
of  the  connective  tissue  and  (as  ossein)  of  the  organic  substances  of 
the  bony  structure.  It  also  occurs  in  the  cartilaginous  tissues  as 
chief  constituent,  but  it  is  here  mixed  with  other  substances,  pro- 
ducing what  was  formerly  called  chondrigen.  Collagen  from 
different  tissues  has  not  quite  the  same  composition,  and  probably 
there  are  several  varieties  of  collagen. 

By  continuously  boiling  with  water  (more  easily  in  the  presence 
of  a  little  acid)  collagen  is  converted  into  gelatine.  Hofiieister  " 
found  that  gelatine,  on  being  heated  to  130°  C,  is  again  trans- 
formed into  collagen ;  and  this  last  may  be  considered  as  the  anhy- 
dride of  gelatine.  Collagen  and  gelatine  have  about  the  same 
composition : 

C  H           N  S+0 

Collagen 50.75  6.47  17.86  24.92  (Hofmeister)  « 

(jfelatiue  (from  hartshorn).     49.31  6.55  18.37  25.77  (Mtilder)  * 

Gelatine  (from  bones) 50.00  6.50  17.50  26.00  (Fremt)-* 

Purified  Gelatine 50.14  6.69  18.12  (Paal)* 

The   gelatine   contains   about   0.6^    sulphur,    which   probably 

1  Hoppe-Sevler,  Physiol.  Chem.     Berlin,  1877-81.     S.  97. 

2Zeitschr.  f.  physiol.  Chem.,  Bd.  2. 

'Annal.  d.  Chem.  u.  Pharm.,  Bd.  45. 

*Jahresber.  d.  Chem.,  1854. 

^Ber.  d.  deutsch.  chem,  Gesellsch.,  Bd.  25,  S.  1208. 


54  THE  PEOTEIN  SUBSTANCES. 

belongs  to  the  gelatine  and  does  not  exist  there  as  an  impurity^ 
from  the  proteids. 

The  decomposition  products  of  collagen  are  tlie  same  as  those  of 
gelatine.  Gelatine  under  similar  conditions  as  the  proteids  yields 
amido-acids,  such  as  leucin,  aspartic  and  glutamic  acids,  but  no 
tyrosin,  which  is  especially  important.  Ifc  yields,  on  the  contrary, 
large  quantities  of  glycocoll,  to  which  the  name  gelatine  sugar  is 
given  on  account  of  its  sweet  taste.  Lysin  and  lysatinin  have  also 
been  obtained  from  gelatine  by  Drechsel  and  E.  Fischer.'  On 
putrefaction  gelatine  yields  neither  tyrosin,  indol  nor  skatol,^  in 
which  it  differs  from  the  proteids.  Still  the  aromatic  group  is 
not  absent  in  gelatine,  and  it  acts  like  the  oxidized  proteid,  the 
oxyprotsulphonic  acid,  yielding  benzoic  acid  (Maly'). 

Collagen  is  insoluble  in  water,  salt  solutions,  dilute  acids,  and 
alkalies,  but  it  swells  up  in  dilute  acids.  By  continuous  boiling 
with  water  it  is  converted  into  gelatine.  It  is  dissolved  by  the 
gastric  juice  and  also  by  the  pancreatic  juice  (trypsin  solution) 
when  it  has  previously  been  treated  with  acid  or  heated  with  water 
above  +  70°  C.^  By  the  action  of  ferrous  sulphate,  corrosive  sub- 
limate, or  tannic  acid,  collagen  shrinks  greatly.  Collagen  treated 
by  these  bodies  does  not  putrefy,  and  tannic  acid  is  therefore  of 
great  importance  in  the  preparation  of  leather. 

Gelatine  or  glutin  is  colorless,  amorphous,  and  transparent  in 
thin  layers.  It  swells  in  cold  water  without  dissolving.  It  dissolves 
in  warm  water,  forming  a  sticky  liquid,  which  solidifies  on  cooling 
when  sufficiently  concentrated.  The  quantity  of  ash  contained  in 
gelatine  is  of  the  greatest  importance  in  the  gelatinization  of  gela- 
tine solutions,  as  shown  by  0.  Nasse  and  A.  Kruger,'  namely,  a 
diminished  quantity  of  ash  diminishes  the  gelatinization  power. 

Gelatine  solutions  are  not  precipitated  on  boiling,  neither  by 
mineral  acids,  acetic  acid,  alum,  lead  acetate,  nor  mineral  salts  in 
general.  A  gelatine  solution  acidified  with  acetic  acid  may  be  pre- 
cipitated by  potassium  ferrocyanide  on  carefully  adding  the  reagent, 

'  See  Drechsel,  Der  Abbau  der  Eiweisskorper.  Du  Bois-Reymoud's  Archiv, 
1891. 

"^  See  literature  on  tlie  cleavage  products  of  gelatine  :  Drechsel  in  Laden- 
burg's  Handworterbuch,  Bd.  3. 

sMonatshefte  f.  Chem.,  Bd.  10. 

*  Kiihne  and  Ewald,  Verh.  d.  naturhist.  med.  Vereins  in  Heidelberg,  1877» 
Bd.  1. 

5  See  Maly's  Jahresber.,  Bd.  19,  S.  29. 


GELATINE.  55 

but  on  the  addition  of  too  much  potassium  ferrocyanide  the  liquid 
remains  clear.  Gelatine  solutions  are  precipitated  by  tannic  acid 
in  the  presence  of  salt;  by  acetic  acid  and  common  salt  in  sub- 
stance; mercuric  chloride  in  the  presence  of  IICl  and  NaCl;  meta- 
phosphoric  acid,  phosphomolybdic  acid  in  the  presence  of  acid  ;  and 
lastly  by  alcohol,  especially  when  neutral  salts  are  present.  Gela- 
tine solutions  do  not  diffuse.  Gelatine  gives  the  biuret  reaction,  but 
not  AuAMKiEWicz's.  It  gives  Millon's  reaction  and  the  xantho- 
proteic acid  reaction  so  faintly  that  it  probably  occurs  from  an 
impurity  consisting  of  proteids. 

By  continuous  boiling  with  water  glutin  is  converted  into  a 
non-gelatinizing  modification  called  yS-glutin  by  Nasse.  According 
to  Nasse  and  Kruger  the  specific  rotatory  power  is  hereby  reduced 
from  —  167°. 5  to  about  —  136°.  On  long-continued  boiling  with 
water,  especially  ^n  the  presence  of  dilute  acids,  also  in  the  gastric 
or  tryptic  digestion,  the  gelatine  is  transformed  into  gelatine  albu- 
moses,  so-called  geJatoses  and  gelatine  peptones.,  which  dift"use  more 
or  less  readily. 

According  to  Hofmetster  '  two  new  substances,  semiglutin  and 
hemicoUin,  are  formed.  The  former  is  insoluble  in  alcohol  of  70- 
80^  and  is  precipitated  by  platinum  chloride.  The  latter,  which 
is  not  precipitated  by  platinum  chloride,  is  soluble  in  alcohol. 
CniTTENDEK  aud  Solley  '^  have  obtained  in  the  peptic  and  tryptic 
digestion  a  proto-  and  a  deuterogelatose,  besides  some  true  peptone. 
The  elementary  composition  of  the  gelatoses  does  not  essentially 
differ  from  that  of  the  gelatine.  Paal*  has  prej^ared  gelatine 
peptone  hydrochlorides  f  I'om  gelatine  by  the  action  of  dilute  hydro- 
chloric acid.  Some  of  these  salts  are  soluble  in  ethyl  and  methyl 
alcohol,  and  others  insoluble  therein.  The  peptones  obtained  from 
these  salts  contain  less  carbon  and  more  hydrogen  than  the  glutin 
from  which  they  originated,  showing  that  hydration  has  taken 
place.  The  molecular  weight  of  the  gelatine  peptone  as  determined 
by  PA.AL  by  Raoult's  method  was  300  to  353,  while  that  for 
gelatine  was  878  to  960. 

Collagen  may  be  obtained  from  bones  by  extracting  them  with 
hydrochloric  acid  (which  dissolves  the  earthy  phosphates)  and  then 
carefully  removing  the  acid  with  water.     It  may  be  obtained  from 

'Zeitscbr.  f   physiol.  ('hem.,  Bd.  3. 

'Journ.  of  physiol.,  Vol.  13. 

'Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  35. 


56  THE  PROTEIN  SUBSTANCES. 

tendons  by  extracting  with  lime-water  or  dilute  alkali  (which  dis- 
solve the  proteids  and  mucin)  and  then  thoroughly  washing  with 
water.  Gelatine  is  obtained  by  boiling  collagen  with  water.  The 
finest  commercial  gelatine  always  contains  a  little  proteid,  which 
may  be  removed  by  allowing  the  finely  divided  gelatine  to  swell  up 
in  water  and  thoroughly  extracting  with  large  quantities  of  fresh 
water.     Then  dissolve  in  warm  water  and  precipitate  with  alcohol. 

Chondrin  or  cartilage  gelatine  is  only  a  mixture  of  glutin  with  tLe  specific 
constituents  of  the  cartilage  and  their  transformation  products. 

Reticulin.  The  reticular  tissues  of  the  lymphatic  glands  con- 
tain a  variety  of  fibres  which  have  also  been  found  by  Mall  '  in  the 
spleen,  intestinal  mucosa,  liver,  kidneys,  and  lungs.  These  fibres 
consist  of  a  special  substance,  reticulin,  investigated  by  Siegfried.' 

Reticulin  has  the  following  composition:  C  52.88;  H  6.97; 
^  15.63;  S  1.88;  P  0.34;  ash  2.27.  The  phosphorus  occurs  in 
organic  combination.  It  yields  no  tyrosin  on  splitting  with  hydro- 
chloric acid.  It  yields,  on  the  contrary,  sulphuretted  hydrogen, 
ammonia,  lysin,  lysatinin,  and  amido-valerianic  acid.  On  con- 
tinuous boiling  with  water,  or  more  readily  with  dilute  alkalies, 
reticulin  is  converted  into  a  body  which  is  precipitated  by  acetic 
a,cid,  and  at  the  same  time  phosphorus  is  split  off. 

Eeticulin  is  insoluble  in  water,  alcohol,  ether,  lime-water, 
sodium  carbonate,  and  dilute  mineral  acids.  It  is  dissolved,  after 
several  weeks,  on  standing  with  caustic  soda  at  the  ordinary  tem- 
perature. Pepsin  hydrochloric  acid  or  trypsin  do  not  dissolve  it. 
Eeticulin  responds  to  the  biuret,  xanthoproteic,  and  Adamkiewicz's 
reactions,  but  not  with  Millon's  reagent. 

It  may  be  prepared  as  follows,  according  to  Siegfried:  Digest 
intestinal  mucosa  with  trypsin  and  alkali.  Wash  the  residue,  extract 
with  ether,  and  digest  again  with  trypsin  and  then  treat  with 
alcohol  and  ether.  On  careful  boiling  with  water  the  collagen 
present  either  as  contamination  or  as  a  combination  with  reticulin 
is  removed.     The  thoroughly  dried  residue  consists  of  reticulin. 

Skeletins  are  a  number  of  nitrogenized  substances  which  form 
the  skeletal  tissue  of  various  classes  of  invertebrates  so  designated 
by  Krukenberg.'  These  substances  are  chitin.^  sjjongin,  con- 
chiolin,  cornein,  a,ndJibroin  (silk).     Of  these  chitin  does  not  belong 

Abhandl.  d.  math.-phys.  Klasse  d.  kgl.  sachs.  Gesellsch.  d.  Wiss.,  1891. 
'  Ueber  die  chemischen  Eigenschaften  des  reticulirten  Gewebes.     Inaugural 
dissertation.     Leipzig,  1892. 

3  Grundziige  einer  vergl.  Physiol,  d.  thier.  Gerilstsubst.     Heidelberg,  1885. 


SKELETINS.  57 

to  the  protein  substances,  and  fibroin  (silk)  is  hardly  to  be  classed 
as  a  skeletin.  Only  those  so-called  skeletins  will  be  given  that 
actually  belong  to  the  protein  group. 

Spongin  forms  the  chief  mass  of  the  ordinary  sponge.  It  gives  no  gelatine 
on  boiling  with  acids,  but  yields  leucin  and  glycocoll  and  no  tyrosin.  Zalo- 
COSTAS'  claims  to  have  found  tyrosin  and  also  butalanin  and  glycalaniu 
(0511,2X204).  Conchiolin  is  found  in  the  shells  of  mussels  and  snails  and  also 
in  the  egg-shells  of  these  animals.  It  yields  leucin  but  no  tyrosin.  The  Byssus 
contains  a  substance,  clo.seIy  related  to  conchiolin,  which  is  soluble  with 
difficulty.  Cornein  forms  the  axial  system  of  the  Antipathes  and  Gorgonia.  It 
gives  leucin  and  a  crystallizable  substance,  cornicrystaUin  (Krukenbero). 
Fibroin  and  Sericin  are  the  two  chief  constituents  of  raw  silk.  By  the  action 
of  superheated  water  the  sericin  dissolves  and  gelatinizes  on  cooling  (silk 
gelatine),  while  the  more  difficultly  soluble  fibroin  remains  undissolved  in  the 
shape  of  the  original  fibre.  On  boiling  with  acid  the  fibroin  yields  alanin 
(Weti.^j,  glycocoll,  and  a  great  deal  (5-8^)  of  tyrosin.  Fibroin  is  dissolved  in 
cold  concentrated  hydrochloric  acid  with  the  expulsion  of  \%  nitrogen  as 
ammonia,  and  it  is  converted  into  another,  nearly  related  substance  called 
sericoin  (Wetl).  Sericin  yields  no  glycocoll,  but  leucin  and  a  crystallizable 
substance  called  seri/i  (amidoethylenlactic  acid).  The  composition  of  the 
above-mentioned  bodies  is  as  follows  : 

C  H  N          S  O 

Conchiolin  (from  snail-eggs)  50.93  6.88  17.86  0.31  24.34  (Krukenberg)' 

Spongin 46.50  6.30  16.20  0.5  27.50  (CroockewittV 

48.75  6.35  16.40  (Posselt)^ 

Cornein 48.96  5.90  16.81  ....  28  33  (Krckenberg)« 

Fibroin 48.23  6.27  18.31  27.19  (Cramer)'' 

"      48.30  6.50  19.20  26.00  (Vignon)^ 

Sericin 44.32  6.18  18.30  30.20  (Cramer) 

Amyloid,  so  called  by  Virchow,  is  a  protein  substance  appear- 
ing under  pathological  conditions  in  the  internal  organs,  such  as 
the  spleen,  liver,  and  kidneys,  as  infiltrations;  and  in  serous  mem- 
branes as  granules  with  concentric  layers.  It  probably  also  occurs 
as  a  constituent  of  certain  prostate  calculi.  Amyloid  has  not  been 
obtained  jDure,  therefore  its  composition  cannot  be  given  with  cer- 
tainty. Friedreich  and  Kbkule  '  found  C  53.6;  H  7.0;  N  15.0; 
and  S  +  0  24.4^.  Kuhne  and  Rudxeff'"  found  l.Sfo  sulphur. 
Amyloid  is  not  related  to  the  carbohydrates  in  the  ordinary  sense, 
and  on  boiling  with  acids  it  gives  neither  glucose  nor  any  other 

'  Compt.  rend.,  Tome  107. 

'  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  21. 

3  Ibid.,  Bd.  18,  and  Zeitschr.  f   Biologie,  Bd.  22. 

*  Anna!,  d.  Chem.  u.  Pharm..  Bd.  48. 
'  Ibid.,  Bd.  45. 

*  Ber.  d,  deutsch.  chem.  Gesellsch.,  Bd.  17. 
■"  Jouru.  f.  prakt.  Chem.,  Bd.  96. 

*  Compt.  rend..  Tome  115. 

'  Virchow's  Archiv,  Bd.  16. 
"  Ibid.,  Bd.  33. 


58  TEE  PROTEIN  SUBSTANCES. 

reducing  substance.  On  the  contrary,  it  yields  leucin  and  tyrosin. 
According  to  Krawkow,'  amyloid  yields  a  residue  similar  to  chitin 
on  boiling  with  strong  caustic  alkali. 

It  is  insoluble  in  water,  alcohol,  ether,  dilute  hydrochloric  acid, 
and  acetic  acid.  It  is  dissolved  in  concentrated  hydrochloric  acid 
or  caustic  alkali,  and  is  converted  into  acid  or  alkali  albuminates 
depending  upon  the  agents  employed.  According  to  Kostjurijst,^ 
amyloid  is  dissolved  by  the  gastric  juice,  which  is  the  reverse  of 
older  theories.  A.  Tschermak  '  found  that  the  amyloid  from  the 
liver  and  spleen  was  readily  soluble  in  alkalies,  less  soluble  in 
organic  acids  and  mineral  acid,  as  well  as  by  peptic  or  tryptic 
digestion  or  by  heating  in  sealed  tubes  with  water.  First  soluble, 
unchanged  amyloid  is  formed,  which  is  then  transformed  into  albu- 
minates, albumoses,  and  peptones.  All  these  products  give  the 
same  color  reactions  as  the  mother-substance.  Tschermak  con- 
siders amyloid  as  a  coagulated  proteid.  Amyloid  gives  the  xantho- 
proteic reaction  and  the  reactions  of  MiLLOisr  and  Adamkiewicz. 
Its  most  important  property  is  its  behavior  with  certain  coloring 
matters.  It  is  colored  reddish  brown  or  a  dingy  violet  by  iodine; 
a  violet  or  blue  by  iodine  and  sulphuric  acid ;  red  by  methylaniline 
iodide,  especially  on  the  addition  of  acetic  acid ;  and  red  by  aniline 
green. 

Amyloid  is  prepared  by  extracting  the  tissue  with  cold  and  then 
boiling  water,  afterwards  with  alcohol  and  ether.  After  boiling 
with  alcohol  containing  hydrochloric  acid  and  digesting  with  gastric 
juice,  that  which  is  insoluble  is  considered  as  amyloid.  As  the 
amyloid  may  be  dissolved  by  the  gastric  juice  (Kostjurin),  the 
utility  of  this  method  seems  doubtful. 

'  Centralbl.  f.  d.  med.  Wissenscli,  1892. 

5  Wien.  med.  Jahrbuclier,  1886.    Cit.  from  Maly's  Jaliresber.,  Bd.  16,  S.  32. 

2  Zeitschr.  f.  pliysiol.  Chem.,  Bd.  20. 


CHAPTER  III. 

THE   CARBOHYDRATES. 

We  designate  with  this  name  bodies  which  occur  especially 
abundant  in  the  plant  kingdom.  As  the  protein  bodies  form  the 
chief  portion  of  the  solids  in  animal  tissues,  so  the  carbohydrates 
form  the  chief  portion  of  the  dry  substance  of  the  plant  structure. 
They  occur  in  the  animal  kingdom  only  in  proportionately  small 
quantities  either  free  or  in  combinations  with  more  complex  mole- 
cules, forming  compound  proteids.  Carbohydrates  are  of  extraor- 
dinarily great  importance  as  food  for  both  man  and  animals. 

The  carbohydrates  contain  carhoii,  hydrogen^  and  oxygen.  The 
last  two  elements  occur  in  the  same  proportion  as  they  do  in  water, 
namely,  2:1,  and  this  is  the  reason  why  the  name  carbohydrates 
has  been  given  to  tbem.  This  name  is  not  quite  pertinent,  if 
strictly  considered;  because  even  though  we  have  bodies,  such  as 
acetic  acid  and  lactic,  which  are  not  carbohydrates  and  still  have 
their  oxygen  and  hydrogen  in  the  relationship  to  form  water,  never- 
theless we  also  have  sugars  (rhamnose,  C^H.^OJ  which  have  these 
two  elements  in  another  proportion.  Heretofore  it  was  thought 
possible  to  characterize  as  carbohydrates  those  bodies  which  con- 
tained 6  atoms  of  carbon,  or  a  multijole,  in  the  molecule,  but  this 
is  not  considered  valid  at  the  present  time.  We  have  true  carbohy- 
drates containing  less  than  6  and  also  those  containing  7,  8,  and  9 
carbon  atoms  in  the  molecule.  The  carbohydrates  have  no  proper- 
ties or  characteristics  in  general  which  differentiate  them  from 
other  bodies;  on  the  contrary,  the  various  carbohydrates  are  in 
many  cases  very  different  in  their  external  properties.  Under 
these  circumstances  it  is  very  difficult  to  give  a  positive  definition 
of  carbohydrates. 

From  a  chemical  standpoint  we  can  say  that  all  carbohydrates 
are  aldehyde  or  ketone  derivatives  of  hexatomic  alcohols.     The 

59 


60  THE  CABBOHi URATES. 

simplest  carbohydrates,  the  simple  sugars  or  monosaccharides,  are 
either  aldehyde  or  ketone  derivatives  of  these  alcohols,  and  the  more 
complex  carbohydrates  seem  to  be  derived  from  these  by  the  forma- 
tion of  anhydrides.  It  is  a  fact  that  the  more  complex  carbo- 
hydrates yield  two  or  even  more  molecules  of  the  simple  sugars 
when  made  to  undergo  hydrolytie  splitting. 

The  carbohydrates  are  generally  divided  into  three  chief  groups, 
namely,  monosacchajides,  disaccharides,  and  polysaccliarides. 

Our  knowledge  of  the  carbohydrates  and  their  structural  rela- 
tionships have  been  very  much  extended  by  the  pioneering  investi- 
gations of  KiLiANi '  and  especially  those  of  E.  Fischer.' 

As  the  carbohydrates  occur  chiefly  in  the  plant  kingdom  it  is 
naturally  not  the  place  here  to  give  a  complete  discussion  of  the 
numerous  carbohydrates  known  up  to  the  present  time.  According 
to  the  plan  of  this  work  it  is  only  possible  to  give  a  short  review  of 
those  carbohydrates  which  occur  in  the  animal  kingdom  or  are  of 
special  importance  as  food  for  man  and  animals. 

Monosaccliaricles. 

All  varieties  of  sugars,  the  monosaccharides  as  well  as  disaccha- 
rides, are  characterized  by  the  termination  "  ose,"  to  which  a  root 
is  added  signifying  their  origin  or  other  relations.  According  to 
the  number  of  carbon  atoms  contained  in  the  molecule  the  mono- 
saccharides are  divided  into  Hoses,  tetroses,  pentoses,  hexoses, 
heptoses,  and  so  on. 

All  monosaccharides  are  either  aldehydes  or  ketones  of  hex- 
atomic  alcohols.  The  first  are  termed  aldoses  and  the  other  heioses. 
Ordinary  glucose  is  an  aldose,  while  ordinary  fruit-sugar  (fructose) 
is  a  ketose.  The  difference  may  be  shown  by  the  structural 
formula  of  these  two  varieties  of  sugar : 

Glucose  =  CH,(OH).CH(OH).0H(OH).0H(OH).CH(OH).0HO; 
Fructose  =  OH,(OH).CH(OH).CH(OH).CH(OH).CO.CH,(OH). 

A  difference  is  also  observed  on  oxidation.  Thj  aldoses  can  be 
converted  into  oxyacids  having  the  same  quantity  of  carbon,  while 

'  Ber.  d.  deutscli.  chem.  Gesellscli.,  Bdd.  18,  19,  and  20. 

*  See  E.  Fischer's  lecture:  "  Syntliesen  in  der  Zuckergruppe,"  Ber.  d. 
deutsch.  chem.  Gesellsch.,  Bd.  33,  S.  2114.  An  excellent  work  on  Carbohydrates 
is  Tollen's  "  Kurzes  Handbuch  der  Kohlehydrate,"  Breslau,  1888,  which  gives 
a  complete  review  of  the  literature, 


MONOSACCHARIDES  61 

the  ketoses  yield  acids  having  less  carbon.  On  mild  oxidation  the 
aldoses  yield  monobasic  oxyacids  and  dibasic  acids  on  more  energetic 
oxidation.  Thus  ordinary  glucose  yields  gluconic  acid  in  the  first 
case  and  saccharic  acid  in  the  second. 

Gluconic  acid  =  CH,(OH).[CH(OH)],.COOH; 
Saccharic  acid  =  COOH.[CH(OH)],.OOOH. 

The  monobasic  oxyacids  are  of  the  greatest  importance  in  the 
artificial  formation  of  the  monosaccharides.  These  acids,  as  lac- 
tones, can  be  converted  into  their  respective  aldehydes  (correspond- 
ing to  the  sugars)  by  the  action  of  nascent  hydrogen.  On  the 
other  hand  they  may  be  transformed  into  stereo-isomeric  acids  on 
heating  with  chinolin,  pyridin,  etc.,  and  the  stereo-isomeric  sugars 
may  be  obtained  from  these  by  reduction. 

Numerous  isomers  occur  among  the  monosaccharides,  and  espe- 
cially in  the  hexose  group.  In  certain  cases,  as  for  instance  in 
glucose  and  fructose,  we  are  dealing  with  a  different  constitution 
(aldoses  and  ketoses),  but  in  most  cases  we  have  stereo-isomerism 
due  to  the  presence  of  asymmetric  carbon  atoms. 

The  monosaccharides  are  converted  into  the  corresponding 
alcohols  by  nascent  hydrogen.  Thus  akabinose,  which  is  a 
pentose,  CJI,„Oj,  is  transformed  into  the  pentatomic  alcohol, 
ARABiT,  CjHjjOj.  The  three  hexoses,  glucose,  fructose,  and 
GALACTOSE,  0^11,^0^,  are  transformed  into  the  corresponding  three 
hexatomic  alcohols,  sorbite,  mannite,  and  dulcite,  C^H.^O^. 
Inversely,  the  corresponding  sugars  may  be  prepared  from  their 
alcohols  by  careful  oxidation. 

Similar  to  the  ordinary  aldehydes  and  ketones  the  sugars  may 
be  made  to  take  up  hydrocyanic  acid.  Cyanhydrines  are  thus 
formed.  These  addition  products  are  of  special  interest  in  that 
they  make  the  artificial  preparation  possible  of  sugars  rich  in  carbon 
from  sugars  poor  in  carbon. 

As  example,  if  we  start  from  glucose  we  obtain  glucocyanlaydrin  on  the 
addition  of  hydrocyanic  acid  :  CH2(OH).[CH(OH)]4.COH  -j-  HCN  =  CHslOH). 
[CH(0H)]4.CH(0H).CN.  On  the  saponification  of  glucocvanhydrin  the  cor- 
responding oxyacid  is  formed:  CHa(OH).[CH(OH)]4.CH(6H).CN  +  2HjO  = 
CHj(0H).[CH(OH)]4,CH(OH).C00H  +  NHg.  By  the  action  of  nascent  hydrogen 
on  the  lactone  of  this  acid  we  obtain  glucoheptose,  C7Hi40t. 

The  monosaccharides  give  the  corresponding  oximes  with  hydro- 
xylamin;  thus  glucose  yields  glucosoxime,  CH,(OII).[CH(OH)]^. 
CH  :  N.OH.     These  combinations  are  of  importance  on  account  of 


62  THE  CARBOIITDRATES. 

the  fact,  as  found  by  Wohl,'  that  they  are  the  starting-point  in  the 
building  up  of  varieties  of  sugars,  namely,  the  preparation  of 
sugars  poor  in  carbon  from  those  rich  in  carbon. 

The  monosaccharides  are  strong  reducing  bodies,  similar  to  the 
aldehydes.  They  reduce  metallic  silver  from  ammoniacal  silver 
solutions,  and  also  several  metallic  oxides,  such  as  copper,  bismuth, 
and  mercury  oxides,  on  warming  their  alkaline  solutions.  This 
property  is  of  the  greatest  importance  in  their  detection  and  quan- 
titative estimation. 

The  behavior  of  the  sugars  to  phenylhydrazin  acetate  is  of 
special  importance.  Their  watery  solutions  first  yield  hydra- 
zones  with  phenylhydrazin  acetate,  and  then  osazones  on  lengthy 
warming  in  the  water-bath.     The  reaction  takes  place  as  follows: 

(a)  CH2(OH).[CH(OH)]3.CH(OH).CHO  +  H^N.NH.C.Hs 

=  CH2(OH).[CH(OH)]3.CH(OH)CH  :  N.NH.C.Hj  +  H^O. 
Plienylglucoshydrazon . 

(6)  CH2(OH)[CH(OH)]3.CH(OH).CH  :  N.NH.CeHs  +  HjN.NH.CaHs 
=  CH2(OH).[CH(OH)]3.C  :  CH  •  N.NH.CsHs 

N.NH.CeHs-fHaO  +  H,. 
Phenylglucosazon. 

The  hydrogen  is  not  evolved,  but  acts  on  a  second  molecule  of  phenylhy- 
drazon  and  splits  it  into  anilin  and  ammonia : 

H,N.NH.C,H5  +  Hj  =  H.N.CeHs  +  NH3. 

The  osazones  are  yellow  crystalline  combinations,  which  differ 
from  each  other  in  melting-point,  solubility,  and  optical  properties 
and  hence  have  received  great  importance  in  the  characterization  of 
certain  sugars.  They  have  also  become  of  extraordinarily  great 
importance  in  the  study  of  the  carbohydrates  for  other  reasons. 
Thus  they  are  very  good  means  of  precipitating  sugars  from  solu- 
tion in  which  they  occur  mixed  with  other  bodies,  and  they  are  of 
the  greatest  importance  in  the  artificial  preparation  of  sugars. 

On  splitting,  by  the  short  action  of  gentle  heat  and  fuming 
hydrochloric  acid,  the  osazones  yield  phenylhydrazin  hydrochloride 
and  so-called  osones,  bodies  which  are  ketoaldehydes : 

CH,(0H).[CH(0H)]3.C.CH:N.NH.C,H, 

N.  NH.  0,H,         +  3H,0  +  2HC1 
=  2C.H,.NH.NH,.HC1  -f  CH,(0H).[CH(0H)]3.C0.CH0. 

Osone. 
'  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  26,  S.  730. 


MONOSACCHARIDES.  63 

The  ketoses  are  obtained  from  the  osones  by  reduction  with  ziuc 
dust  and  acetic  acid  : 

CH,(0H).[CH(0H)]3C0.CH0  +  2H 

=  CH,(OH).[CH(OH)],.CO.CH,(OH). 

If  we  start  with  an  aldose,  we  do  not  get  the  same  sugar  back 
again,  but  an  isomere  ketose,  and  in  this  way  we  can  convert  glucose 
into  fructose. 

We  can  also  pass  from  the  osazones  to  the  corresponding  sugars 
(ketoses)  in  other  ways,  namely,  by  direct  reduction  of  the  osazones 
with  acetic  acid  and  zinc  dust.  The  corresponding  osamin  is  first 
formed,  and  then  on  treating  with  nitrous  acid  a  ketose  is  obtained : 

CH,(0H).[CH(0H)]3.C.CH:X.XH.C,H, 

N.NH.C.H,  +  H,0  +  4H  = 

Phenylglucosazon. 

CH,(OH).[CH(OH)],.CO.CH,(NHJ+C,H,NH.NH,+C.H,.NH, 

Isoglucosamin. 

and 

CH,(0H).[CH(0H)]3.C0.CH,(NHJ  +  HXO, 

=  CH,(OH).[CH(OH)]3.CO.CH3(OH)  +  N,  +  H,0. 

Fructose. 

From  what  has  been  stated  we  see  that  there  are  various  ways 
of  preparing  sugars  artificially.  They  may  be  prepared  (1)  by  the 
careful  oxidation  of  the  related  alcohols;  (2)  reduction  of  the  corre- 
sponding monobasic  oxyacids;  (3)  splitting  of  the  osazone  with 
hydrochloric  acid  and  a  reduction  of  the  osone;  (4)  direct  reduction 
of  the  osazone  and  treating  the  osamin  with  nitrous  acid;  (5) 
syntheses  from  combinations  poor  in  carbon  (see  syntheses  of  the 
hexoses). 

The  monosaccharides  are  colorless  and  odorless  bodies,  neutral  in 
reaction,  with  a  sweet  taste,  readily  soluble  in  water,  generally  solu- 
ble with  diflQculty  in  absolute  alcohol,  and  insoluble  in  ether,  and 
some  of  which  crystallize  well  in  the  pure  state.  They  are  optically 
active,  some  Isevorotatory  and  others  dextrorotatory^  but  there  are 
also  optically  inactive  modifications  (racemic),  which  are  formed 
from  two  optically  opposed  components. 

We  designate  the  optical  activity  of  the  carbohydrates  with  the 
letter  1-  for  laevogyrate,  d-  for  dextrogyrate,  and  i-  for  inactive. 
These   are   only   partly   useful.     Thus   dextrorotatory   glucose   is 


64  THE  CARBOHYDRATES. 

designated  d-glucose,  la?vorotatory  1-glucose,  and  the  inactive 
i-glncose.  Emil  Fischer  has  nsed  these  signs  in  another  sense. 
He  designates  by  these  signs  the  homogeneousness  of  the  various 
kinds  of  sugars  instead  of  their  optical  activity.  For  example,  he 
does  not  designate  the  laevorotatory  fructose,  1-fructose,  but 
d-fructose,  showing  its  close  relation  to  dextrorotatory  d-glucose. 
This  designation  is  generally  accepted,  and  the  above-mentioned 
signs  only  show  the  optical  properties  in  a  few  cases. 

Specific  rotation  means  the  rotation  in  degrees  produced  by  1  gm.  substance 
dissolved  in  1  cc.  liquid  placed  in  a  tube  1  d.  cm.  long,  The  reading  is  ordi- 
narily made  at  -)-  30°  C.  and  with  a  homogeneous  sodium  light.  The  sp.  rota- 
tion with  this  light  is  represented  by  a(D),  and  is  expressed  by  the  following- 
formula  ;  a(D)  =  ±  ,  in  which  a  represents  the  reading  of  degrees,  1  the 

length  of  the  tube  in  decimetres,  and  p  the  weight  of  substance  in  1  cc. 
of  the  liquid.     Inversely  the  per  cent  P  of  substance  can  be  calculated,  when 

the  specific  rotation  is  known,  by  the  formula  P  =  — — ,  in  which  s  represents 

the  known  specific  rotation. 

A  freshly  prepared  sugar  solution  often  shows  another  rotation  form,  when 
it  is  allowed  to  stand  for  some  time.  If  the  rotation  gradually  diminishes,  this 
is  called  birotation,  while  a  gradual  increase  in  the  rotation  is  called  half -rotation. 
The  birotation  and  half-rotation  may  be  immediately  abolished  by  the  addition 
of  very  little  ammonia  (1  p,  m.).     C.  Schultze  and  Tolliks.'  , 

Many  monosaccharides,  but  not  all,  ferment  with  yeast,  and  it 
has  been  shown  that  only  those  varieties  of  sugar  containing  3,  6, 
or  9  atoms  of  carbon  in  the  molecule  are  fermentable  with  yeast. 
Still  amongst  the  hexoses  we  find  exceptions,  namely,  a  few  artifi- 
cially prepared  hexoses  do  not  ferment  with  yeast.  Various  kinds 
of  schizomycetes  cause  a  different  fermentation,  such  as  lactic  and 
butyric  acid  fermentation  and  mucilaginous  fermentation. 

The  simple  varieties  of  sugar  occur  in  part  in  nature  as  such 
already  formed,  which  is  the  case  with,  both  of  the  very  important 
sugars,  grape-sagar  and  fructose.  They  also  occur  in  great  abund- 
ance in  nature  as  more  complex  carbohydrates  (di-  and  polysaccha- 
rides) ;  also  as  ester  combinations  with  different  substances,  as 
so-called  glucosides. 

Among  the  groups  of  monosaccharides  known  at  the  present 
time,  those  containing  less  than  five  and  more  than  six  carbon 
atoms  in  the  molecule  have  no  great  importance  in  zoo-chemistry, 
although  they  are  of  high  scientific  interest.  Of  the  other  two 
groups  the  hexoses  are  of  the  greatest  importance,  because  in  the 

'  Annal.  d.  Chem.  u.  Pharm.,  Bd.  271. 


PENTOSES.  65 

past  only  tliose  carbohydrates  with  six  carbon  atoms  were  considered 
as  true  carbohydrates.  As  the  pentoses  have  been  the  snbject  of 
zoo-chemical  investigations  of  late,  they  will  also  be  given  in  short. 

Pentoses  (C,H,„OJ. 

As  a  rale  the  pentoses  do  not  occur  as  such  in  nature,  but  are 
formed  in  the  hydrolytic  splitting  of  several  complex  carbohydrates, 
the  so-called  pentosanes,  especially  on  boiling  gums  with  dilute 
mineral  acids.  They  exist  very  widely  distributed  in  the  j)lant 
kingdom,  and  are  especially  of  great  importance  in  the  building  up 
of  certain  plant  constituents.  They  have  only  thus  far  been  found 
in  exceptional  cases  in  animals.  Salkowski  and  Jastrowitz  ' 
have  found  a  pentose  in  the  urine  of  those  addicted  to  the  morphine 
habit.  A  pentose  has  been  found  by  the  author''  amongst  the 
cleavage  products  of  a  uncleoproteid  from  the  pancreas. 

The  pentoses  seem  to  be  of  importance  as  food  for  herbivorous 
animals.  Salkowski  ^  and  Cremer  '  have  shown  that  the  pentoses 
xylose,  arabinose,  and  rhamnose  are  absorbed  by  rabbits  and  hens, 
and  that  these  animals  utilize  the  pentoses,  and  even  form  glycogen 
therefrom.  The  pentoses  seem  to  be  absorbed  by  human  beings, 
but  the  views  in  regard  to  their  assimilation  are  somewhat  disputed.* 

The  pentoses  are  non-fermentable,  reducible  aldoses.  On  heat- 
ing with  sulphuric  or  hydrochloric  acids  they  yield  f urfurol,  but  no 
levulinic  acid.  The  furfurol  passing  over  on  distilling  with  hydro- 
chloric acid  may  not  only  be  used  in  the  detection  (with  aniline 
acetate  paper  which  is  colored  red  with  furfurol),  but  also  in  the 
quantitative  estimation  of  pentoses  (or  pentosanes).  On  warming 
with  hydrochloric  acid  containing  phloroglucin  a  beautiful  red 
solution  is  the  result,  and  this  solutiou  gives  a  sharply-defined 
absorption  band  on  the  right  of  the  sodium  line.  The  most  im- 
portant pentoses  are  arabinose  and  xylose. 

Arabinose  (dextro-rotatory  arabinose,  pectin  sugar)  is  obtained 
on  boiling  gum  arable  or  cherry-gum  with  "I'fo  sulphuric  acid.  It 
crystallizes,  has  a  sweet  taste,  melts  at  about  160°,  and  is  strongly 

>  Centralbl.  f.  d.  med.  Wissenscli.,  1892,  S.  337  and  593, 
2  Zeitscbr.  f.  physiol.  Chem.,  Bd.  19. 
•'  Centralbl.  f.  d.  med.  Wissensch.,  1892,  S.  337  and  593. 
4  Zeitscbr.  f.  Biologie,  Bd.  29. 

^  See  Ebstein,  Virchow's  Arch,,  Bd.  129,  and  Cremer,  Zeitscbr.  f.  Biologie, 
Bd.  29. 


66  THE  CARBOHYDRATES. 

dextro-rotatory.  Its  osazon  melts  at  157-158°  C.  The  artificially 
prepared  laevogyrate  as  well  as  the  optically  inactive  arabinose  are 
known. 

Xylose  (wood  sugar).  This  body  is  obtained  with  the  previous 
stereo-isomeric  pentose  on  boiling  wood  gums  with  dilute  acids.  It 
crystallizes,  is  feebly  dextrogyrate,  and  gives  an  osazon,  which 
melts  at  about  160°  C. 

Amongst  the  pentoses  we  have  rihose,  obtained  on  the  reduction  of  the  lac- 
tone of  ribonic  acid,  which  is  produced  from  arobonic  acid.  Rhamnose,  which 
used  to  be  called  isodulcite,  is  a  methylpentose,  CeHuOc ,  and  is  obtained  from 
different  glucosides  (quercitin,  xanthorhamnin,  etc.). 

Hexoses  (C,H,,0,). 

The  most  important  and  best-known  simple  sugars  belong  to 
this  group,  and  the  remaining  bodies  considered  as  carbohydrates 
(with  the  exception  of  arabinose  and  inosite)  are  anhydrides  of  this 
group.  Certain  hexoses,  such  as  dextrose  and  fructose,  occur  in 
nature  already  formed,  while  others  are  produced  by  the  hydrolytic 
splitting  of  other  more  complicated  carbohydrates  or  glucosides. 
Others,  such  as  mannose  or  galactose,  are  formed  by  the  hydrolytic 
cleavage  of  natural  products;  while  some,  on  the  contrary,  such  as 
gulose,  talose,  and  others,  are  obtained  only  by  artificial  means. 

All  hexoses,  as  also  their  anhydrides,  yield  levulinic  acid, 
C^HgOg,  besides  formic  acid  and  humus  substances,  on  boiling  with 
dilute  mineral  acids.  Some  of  the  hexoses  are  fermentable  with 
yeast,  while  the  artificially  prepared  hexoses  do  not,  or  at  least  only 
with  great  difficulty  and  incompletely. 

Some  hexoses  are  aldoses,  while  others  are  ketoses.  Belonging 
to  the  first  group  we  have  mannose,  glucose,  gulose,  galactose, 
and  talose,  and  to  the  otlier  fructose,  and  possibly  also  sorbi- 
nose. We  differentiate  also  between  the  d,  1,  and  i  modifica- 
tions, for  instance,  d-,  1-,  and  i-glucose;  hence  the  number  of 
isomers  is  very  great. 

The  most  important  syntheses  of  the  carbohydrates  have  been 
made  by  E.  Fischer  and  his  pupils  chiefly  within  the  members  of 
the  hexose  group,  A  short  summary  of  the  syntheses  of  hexoses  is 
given  below. 

The  first  artificial  preparation  of  glucose  was  made  by  Butlerow.'  On 
treating  trioxymethylen,    a  polymer    of    formaldehyde,    with    lime-water    he 

'Ann.  d.  Chem.  u.  Pharm.,  Bd.  130,   Compt.  rend.,  Tome  53. 


DEXTROSE.  67 

obtained  a  faintly  sweetisli  syrup  called  methylenitan.  LoEW  '  later  obtained 
about  the  same  ]iroduct  on  the  condensation  of  formaldehyde  in  the  presence 
of  bases,  and  he  called  this  product  formose.  E.  Fischer  '■'  has  shown  that  this 
formose  syrup  consists  of  a  mixture  of  a  nonfernientable  sugar,  formose,  and 
a  fermentable  sugar,  a-itcrose.  This  last-mentioned  hexose  is  the  starting-point 
for  further  syntheses. 

The  name  a-acrose  has  been  given  to  these  bodies  because  they  are  oljtained 
from  acrolein  bromide  by  the  action  of  bases  (Fischek).  They  are  also 
obtained  admixed  with  fi-acwse  on  the  oxidation  of  glycerin  with  bromine  in 
the  presence  of  sodium  carbonate,  and  treating  the  resulting  mixture  of  glycerin, 
aldehyde,  and  dioxyacetoii,  CH2(0H).CH(0H).CH0  and  CH2(OH).CO.CH2(OH) 
with  alkalies.     A  condensation  takes  place  with  the  formation  of  hexoses. 

a-acrose  may  be  isolated  from  the  above  mixture  and  obtained  pure  by  first 
converting  it  into  its  osazon  and  then  retransformiug  this  into  the  sugar, 
a-acrose  is  identical  with  i-fructose.  With  yeast  one-half,  the  loevogyrate 
d-fructose  ferments,  while  the  dextrogyrate  1-fructose  remains.  The  i-  and 
1-fructose  may  be  prepared  in  this  way. 

On  the  reduction  of  a-acrose  we  obtain  a  acrit,  which  is  identical  with 
i-mannite.  On  oxidation  of  i-mannite  we  obtain  i-mannose,  from  which  only 
1-mannose  remains  on  fermentation.  On  further  oxidation  of  i-maunose  it 
yields  i-mann(mic  acid.  The  two  active  mannonic  acids  may  be  separated  from 
each  other  by  the  fractional  crystallization  of  their  strychnin  or  morphin  salts. 
The  two  corresponding  mannoses  may  be  obtained  from  these  two  acids,  d-  and 
1-mannonic  acids,  by  reduction. 

d-fructose  is  obtained  from  d-mannose  by  the  method  given  on  page  63, 
using  the  osazon  as  an  intermediate  step.  The  d-  and  1-mannonic  acids  are 
partly  converted  into  d-  and  1-gluconic  acid  on  heating  with  chinolin,  and  d-  or 
1-glucose  is  obtained  on  the  reduction  of  these  acids.  I-glucose  is  best  prepared 
from  1-arabinose  by  means  of  the  cyanhydrin,  reaction,  using  1-gluconic  acid  as 
the  intermediate  step.  The  combination  of  1-  and  d-gluconic  acid,  forming 
i-gluconic  acid,  yields  i-glucose  on  reduction. 

The  artificial  preparation  of  sugars  by  means  of  condensation  of  formal- 
dehyde has  received  special  interest  because,  according  to  Baeyer's  assimila- 
tion hypothesis  of  plants,  formaldehyde  is  first  formed  by  the  reduction  of 
carbon  dioxide,  and  the  sugars  are  produced  by  the  condensation  of  this  formal- 
dehyde. BoKORNY^  has  shown,  by  special  experiments  on  alg«  Spirogyra,  that 
formaldehyde  sodium  sulphite  was  split  by  the  living  algae  cells.  The  formal 
dehyde  set  free  is  immediately  condensed  to  carbohydrate  and  precipitated  as 
starch. 

Among  the  hexoses  known  at  the  present  time  only  dextrose, 
fructose,  and  galactose  are  really  of  physiological  chemical  interest ; 
therefore  the  obher  hexoses  will  only  be  incidentally  mentioned. 

Dextrose  (d. -glucose),  glycose,  grape-sugar,  and  diabetic 
SUGAR,  occurs  abundantly  in  the  grape,  and  also,  often  accompanied 
with  levnlose  (d. -fructose),  in  honey,  sweet  fruits,  seeds,  roots,  etc. 
It  occurs  in  the  intestinal  tract  during  digestion,  also  in  small 
quantities  in  the  blood  and  lymph,  and  as  traces  in  other  animal 
fluids  and  tissues.     It  only  occurs  as  traces  in  urine  under  normal 

'Journ.  f.  prakt.  Chem.,  Bd.  33,  and  Ber.  d.  deutscli.  cliem,  Gesell.,  Bdd. 
20,  21,  22. 

*Ihid..  Bd.  21. 

»Biolog.  Centralbl.,  Bd.  12,  S.  321  and  481. 


68  TEE  CARBOHYBRArES. 

conditions,  while  in  diabetes  the  quantity  is  very  large.  It  is  formed 
in  the  hydrolytic  cleavage  of  starch,  dextrin,  and  other  compound 
carbohydrates,  as  also  in  the  splitting  of  glucosides. 

Properties  of  Dextrose.  Dextrose  crystallizes  sometimes  with 
1  mol.  water  of  crystallization  in  warty  masses  or  small  leaves  or 
plates,  and  sometimes  when  free  from  water  in  needles.  The  sugar 
containing  water  of  crystallization  melts  even  below  100°  C.  and 
loses  its  water  of  crystallization  at  110°  C,  The  anhydrous  sugar 
melts  at  146°  C,  and  is  converted  into  glucosan,  CJij^O^,  at 
170°  C.  with  the  elimination  of  water.  On  strongly  heating  it  is 
converted  into  caramel  and  then  decomposed. 

Grape-sugar  is  readily  soluble  in  water.  This  solution,  which 
is  not  as  sweet  as  a  cane-sugar  solution  of  the  same  strength,  is 
dextrogyrate  and  shows  strong  birotation.  The  specific  rotation  is 
somewhat  dependent  upon  concentration  of  the  solution,  but  the 
specific  rotation  of  a  watery  solution  of  1-15^  anhydrous  dextrose 
at  +^0°  C.  may  be  considered  as  -\-6'^°.Q.  Dextrose  dissolves 
sparingly  in  cold,  but  more  freely  in  boiling,  alcohol.  100  parts 
alcohol  of  sp.  gr.  0.837  dissolves  1.95  parts  anhydrous  glucose  at 
+  17°. 5  C.  and  27.7  parts  at  the  boiling  temperature  (Akthojst  '). 
Glucose  is  insoluble  in  ether.  If  an  alcoholic  caustic-alkali  solution 
is  added  to  an  alcoholic  solution  of  glucose,  an  amorphous  precipi- 
tate of  insoluble  alkali  compound  is  formed.  On  warming  this 
compound  it  decomposes  easily  with  the  formation  of  a  yellow  or 
brownish  color,  which  is  the  basis  of  the  following  reaction. 

Moore's  Test.  If  a  glucose  solution  is  treated  with  about  ^  of 
its  volume  of  caustic  potash  or  soda  and  warmed,  the  solution 
becomes  first  yellow,  then  orange,  yellowish  brown,  and  lastly  dark 
brown.  It  has  at  the  same  time  a  faint  odor  of  caramel,  and  this 
odor  is  more  pronounced  on  acidification. 

Glucose  forms  many  crystallizable  combinations  with  NaCl,  of 
which  the  easiest  to  obtain  is  (OgHijOJj.JSTaCl  +  H,0,  which  forms 
large  colorless  six-sided  double  pyramids  or  rhomboids  with  13.40^ 
NaCl. 

Glucose  in  neutral  or  very  faintly  acid  (by  an  organic  acid) 
solution  passes  into  alcoholic  fermentation  with  beer-yeast,  CgH,,0„ 
=  2C  H  .OH  +  200,.  The  most  favorable  temperature  for  this 
fermentation  is  34°   0.    according  to  Jodblauer."     Besides  the 

'  Cited  from  Tollens'  Handbucb. 

s  Hoppe-Seyler's  Handbucb,  6,  Auf . ,  1893,  S.  63. 


REACTIONS  FOR  DEXTROSE.  69 

alcohol  and  carbon  dioxide  there  are  formed,  especially  at  higher 
temperatures,  small  quantities  of  homologous  alcohols  (amyl-alco- 
hol),  glycerin,  and  succinic  acid.  In  the  i)resence  of  acid  milk  or 
cheese  the  grape-sugar  passes,  especially  in  the  presence  of  a  base 
such  as  ZnO  or  CaC03,  into  lactic-acid  fermentation.  The  lactic 
acid  may  then  further  pass  into  butyric-acid  fermentation:  2C3HgO, 
=  C,H,0,  +  2C0,  +  4H. 

Grape-sugar  reduces  several  metallic  oxides,  such  as  copper 
oxide,  bismuth  oxide,  mercuric  oxide,  in  alkaline  solutions,  and  the 
most  important  reactions  for  sugar  are  based  on  this  fact. 

Tkommer's  test  is  based  on  the  property  that  glucose  possesses 
of  reducing  copper-hydrated  oxide  in  alkaline  solution  into  sub- 
oxide. Treat  the  glucose  solution  with  about  \-^  vol.  caustic  soda 
and  then  carefully  add  a  dilute  copper-sulphate  solution.  The 
copper-hydrated  oxide  is  thereby  dissolved,  forming  a  beautiful  blue 
solution,  and  the  addition  of  copper  sulphate  is  continued  until  ;i 
n^ery  small  amount  of  hydrate  remains  undissolved  in  the  liquid. 
This  is  now  warmed  and  a  yellow  hydrated  suboxide  or  red  suboxide 
separates  even  below  the  boiling-point.  If  too  little  copper  salt  has 
been  added,  the  test  will  be  yellowish  brown  in  color  as  in  Moore's 
test;  but  if  an  excess  of  copper-salt  has  been  added,  the  excess  of 
hydrate  is  converted  on  boiling  into  a  dark-brown  hydrate  which 
interferes  with  the  test.  To  prevent  these  difficulties  the  so-called 
Fehling's  solution  may  be  employed.  This  reagent  is  obtained 
by  mixing  before  use  equal  volumes  of  an  alkaline  solution  of 
Rochelle  salts  and  a  coj^per-sulphate  solution  (see  Quantitative 
Estimation  of  Sugar  in  the  Urine  in  regard  to  concentration). 
This  solution  is  not  reduced  or  noticeably  changed  by  boiling.  The 
tartrate  holds  the  excess  of  copper-hydrate  oxide  in  solution,  and 
an  excess  of  the  j  eagent  does  not  interfere  in  the  performance  of 
the  test.     In  the  presence  of  sugar  this  solution  is  reduced. 

Bottger-Almeist's  test  is  based  on  the  property  glucose  possesses 
of  reducing  bismuth  oxide  in  alkaline  solution.  The  reagent  best 
adapted  for  this  purpose  is  obtained,  according  to  Nylander's" 
modification  of  Almen's  original  test,  by  dissolving  4  grms. 
Rochelle  salt  in  100  parts  10^  caustic-soda  solution  and  adding 
2  grms.  bismuth  subnitrate  and  digesting  on  the  water-bath  until 
as  much  of  the  bismuth  salt  is  dissolved  as  possible.     If  a  glucose 

'  Zeitsclir.  f.  physiol.  Chem.,  Bd.  8. 


TO  THE  CARBOHTDRATES. 

solution  is  treated  with  about  y^  vol.,  or  with  a  larger  quantity  of 
the  solution  when  large  quantities  of  sugar  are  present,  and  boiled 
for  a  few  minutes,  the  solution  becomes  first  yellow,  then  yellowish 
brown,  and  lastly  nearly  black,  and  after  a  time  a  black  deposit  of 
bismuth  (?)  settles. 

On  heating  with  phentlhydrazin  acetate  a  dextrose  solution 
gives  a  precipitate  consisting  of  fine  yellow  crystalline  needles  which 
are  nearly  insoluble  in  water  but  soluble  in  boiling  alcohol,  and 
which  separate  again  on  treating  the  alcoholic  solution  with  water. 
The  crystalline  precipitate  consists  of  phenylglucosazone.  This 
compound  melts  when  pure  at  304-205°  0. 

Glucose  is  not  precipitated  by  a  lead-acetate  solution,  but  is 
almost  completely  precipitated  by  an  ammoniacal  basic  lead-acetate 
solution.  On  warming  the  precipitate  becomes  flesh-color  or  rose- 
red  (Rubber's  reaction'). 

If  a  watery  solution  of  grape-sugar  is  treated  with  benzoyl- 
chloride  and  an  excess  of  caustic  soda,  and  shaken  until  the  odor 
of  benzoylchloride  has  disappeared,  a  precipitate  of  benzoic-acid 
ester  of  glucose  will  be  produced  which  is  insoluble  in  water  or 
alkali  (Baumann"'). 

If  -J-l  c.c.  of  a  dilute  watery  solution  of  glucose  is  treated  with 
a  few  drops  of  a  15^  alcoholic  solution  of  a-napJithol,  the  liquid  is 
colored  a  beautiful  violet  on  the  addition  of  1-2  c.c.  concentrated 
sulphuric  acid  (Molisch'),  This  reaction  depends  on  the  forma- 
tion of  furfurol  from  the  sugar  by  the  action  of  the  sulphuric  acid. 

DiAZOBENZOL-sui.PiiONrc  ACID  gives  with  a  dextrose  solution  made  allialine 
with  a  fixed  alkali  a  red  color,  after  10-15  minutes  gradually  changing  to  violet. 
Orthonitrophenyl-propiolic  acid  yields  indigo  when  boiled  with  a  small 
quantity  of  sugar  and  sodium  carbonate,  and  this  is  converted  into  indigo-white 
ijy  an  excess  of  sug^ir.  An  alkaline  solution  of  grape-sugar  is  colored  deep  red 
on  being  warmed  with  a  dilute  solution  of  picric  acid. 

A  more  complete  description  as  to  the  performance  of  these 
several  tests  will  be  given  in  detail  in  a  subsequent  chapter  (on  the 
urine). 

Dextrose  is  prepared  pure  by  the  following  simple  method  of 
SoxHLET  and  Tollens,  being  a  modification  of  Schwaz's* 
method : 

'  Zeitschr.  f.  Biologie,  Bd.  20, 

'  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  19  ;  also  Kueny,  Zeitschr.  f.  physiol. 
Chem.,  Bd.  14. 

3  Monatshefte  f.  Chem.,  Bd.  7,  and  Centralbl.  f.  d.  med.  Wissensch,,  1887,. 
S.  34  and  49. 

*  Tollens'  Ilandbuch  der  Kohlehydrate,  S.  39. 


D  FRUCTOSE.  71 

Treat  12  litres  alcohol  with  480  c.c.  fnming  hydrochloric  acid 
and  warm  to  45-50°  C. ;  gradually  add  4  kilos  powdered  cane-sngar, 
and  allow  to  cool  after  heating  for  2  hours,  when  all  the  sugar  will 
have  dissolved  and  been  inverted.  To  incite  crystallization,  some 
crystals  of  anhydrous  dextrose  are  added,  and  after  several  days  the 
crystals  are  sucked  dry  by  the  air-pump,  washed  witii  dilute  ulcohol 
to  remove  hydrochloric  acid  and  crystallized  from  alcohol  or  methyl 
alcohol.  According  to  Tolleists  it  is  best  to  dissolve  the  sugar  in 
one  half  its  weight  of  water  on  the  water-bath  and  then  add  double 
this  volume  of  90-95^  alcohol. 

In  detecting  dextrose  in  animal  fluids  or  extracts  of  tissues  we 
may  make  use  of  the  above-mentioned  reduction-tests,  the  optical 
determination,  the  fermentation,  aud  phenylhydrazin  tests.  For 
the  quantitative  estimation  the  reader  is  referred  to  the  chapter  on 
nrine.  Those  liquids  containing  proteids  must  first  have  these 
removed  by  coagulation  with  heat  and  addition  of  acetic  acid,  or  by 
precipitation  with  alcohol  or  metallic  salts,  before  testing  for 
dextrose.  In  regard  to  the  difficulties  of  operating  with  blood  and 
serous  fluids  we  refer  the  student  to  the  works  of  Schenk,' 
EoHMA2q"]sr,'  Abeles,'  and  Seegen'.'' 

The  guloses  are  stereo-isomers  of  dextrose  and  may  be  prepared  artificially, 
d-gulose  is  obtained  on  tbe  reduction  of  d-gulonic  acid,  which  is  derived  on  the 
reduction  of  glycuronic  acid  (see  chapter  on  urine). 

Mannoses. — d-mannose,  also  called  scminose,  is  obtained  with  d-fructose,  on 
the  careful  oxidation  of  d-inannite.  It  is  also  obtained  on  the  hydrolysis  of 
natural  carbohydrates,  such  as  salep  slime,  and  reserve  cellulose  (especially 
from  the  shavings  from  the  ivory-nut).  It  is  dextrorotatory,  readily  ferments 
with  beer-yeast,  gives  a  hydrazon  not  readily  soluble  in  water,  and  an  osazon 
which  is  identical  with  that  from  d-glucose. 

d-fructose,  also  called  levulose,  fruit-sugar,  occurs,  as 
above  stated,  mixed  with  dextrose  extensively  distributed  in  the 
plant  kingdom  and  also  in  honey.  It  is  formed  in  the  hydrolytic 
cleavage  of  cane-sugar  and  other  carbohydrates,  but  it  is  readily 
obtained  by  the  hydrolytic  splitting  of  inulin.  In  extraordinary 
cases  of  diabetes  mellitus  we  find  fructose  in  the  urine.  This  sugar 
has  won  special  dietetic  importance  in  diabetes  on  account  of  its 
being  readily  assimilated. 

Fructose  crystallizes  with  difficulty  in  needles  partly  anhydrous 
and  partly  containing  water.  It  is  readily  soluble  in  water,  but 
nearly  insoluble  in  cold  absolute  alcohol,  thongh  rather  readily  in 
boiling  alcohol.      Its  watery  solution  is  lasvogyrate,  but  the  state- 

'  Pfliiger's  Archiv,  Bdd.  46  and  47. 
2  C'entralbl.  f.  Physiol.,  Bd.  4. 

*  Zeitschr.  f.  physiol    Chem.,  Bd.  15. 

*  Centralbl.  f.  Plivsiol.,  Bdd.  4  and  8. 


72  2UE  CARDOIIYBRATES. 

ments  in  regard  to  the  specific  rotation  are  quite  variable.  Fructose 
ferments  with  yeast,  and  gives  the  same  reduction  tests  as  dextrose 
and  also  the  same  osazone.  It  gives  a  combination  with  calcium 
which  is  less  soluble  than  the  corresponding  dextrose  combination. 
Fructose,  as  above  stated,  is  best  obtained  by  the  hydrolytic 
splitting  of  innlin,  by  warming  with  faintly  acidulated  water. 

Sorbinose  (sorbin)  is  obtained  from  the  juice  of  the  berry  of  the  mountain 
ash  under  certain  conditions.  It  is  crystalline  and  is  laevogyrate,  and  is  con- 
verted into  sorbit  by  reduction  ,  hence  it  seems  to  be  a  ketose  which  is  stereo- 
isomeric  with  fructose. 

Galactose  (not  to  be  mistaken  for  lactose  or  milk-sugar)  is 
obtained  on  the  hydrolytic  cleavage  of  milk-sugar  and  by  hydrolysis 
of  other  carbohydrates,  especially  varieties  of  gums  and  slime 
bodies.  It  is  also  obtained  on  heating  cerebrin,  a  nitrogenized 
glucoside  prepared  from  the  brain,  with  dilute  mineral  acids. 

It  crystallizes  in  needles  or  leaves,  which  melt  at  168°  0.  It  is 
somewhat  less  soluble  than  dextrose  in  water.  It  is  dextrogyrate, 
and  shows  multirotation.  It  ferments  with  yeast  (alttiough  not  as 
rapidly  as  dextrose) ;  still  the  statements  on  this  subject  are  contra- 
dictory. Galactose  reduces  Feeling's  solution  to  a  less  extent 
than  dextrose,  and  10  c.c.  of  this  solution  are  reduced,  according  to 
SoxHLET,  by  0.0511  gm.  galactose  in  Ifo  solution.  Its  phenylosazon 
melts  at  193°  C.  On  oxidation  it  first  yields  galactonic  acid  and 
then  mncic  acid.  Both  1-  and  i-galactose  have  been  artificially 
prepared. 

Talose  is  a  sugar  which  is  artificially  prepared  by  the  reduction  of  talonic 
acid.  Talonic  acid  is  obtained  from  d-galactonic  acid  by  heating  it  with  chino- 
lin  or  pyridin  to  140-150°  C, 

Disaccbarides, 

Some  of  the  varieties  of  sugar  belonging  to  this  group  occur 
ready  formed  in  nature  Thus  we  have  cane-sugar  and  milk-sugar. 
Some,  on  the  contrary,  such  as  maltose  and  isomaltose,  are  produced 
by  the  partial  hydrolytic  cleavage  of  complicated  carbohydrates. 
Isomaltose  is  besides  this  also  obtained  from  glucose  by  reversion 
(see  below). 

The  disaccbarides  or  hexobioses  are  to  be  considered  as  anhy- 
drides, derived  from  two  monosaccharides  with  the  exit  of  1  mol. 
water.  Corresponding  to  this,  their  general  formula  is  0,^112.^0,,. 
On  hydrolytic  cleavage,  on  the  addition  of  water,  they  yield  two 


(JANE  SUGAR.  73 

molecules  of  liexoses,  and  indeed  either  two  molecules  of  the  same 
hexose  or  two  different  hexoses.     Thus: 

Cane-sugar  +  H^O  =  glucose  +  fructose; 
Maltose       +  H^O  =  glucose  +  glucose; 
Milk-sugar  +  H^O  =  glucose  -f  galactose. 

The  fructose  turns  the  polarized  ray  more  to  the  left  than  the 
glucose  does  to  the  right ;  hence  the  mixture  of  hexoses  obtained  on 
the  cleavage  of  cane-sugar  has  an  opposite  rotation  to  the  cane-sugar 
itself.  On  this  account  the  mixture  is  called  ustvert  sugar,  and 
the  hydrolytic  splitting  is  designated  as  inversion.  This  term 
inversion  is  not  only  used  for  the  splitting  of  cane-sugar,  but  is 
also  used  for  the  hydrolytic  cleavage  of  compound  sugars  into 
monosaccharides.  The  reverse  reaction,  whereby  monosaccharides 
are  condensed  into  complicated  carbohydrates,  is  called  reversion. 

We  subdivide  the  disaccharides  into  two  groups.  One,  to  which 
cane-sugar  belongs,  wliere  the  members  have  not  the  property  of 
reducing  certain  metallic  oxides  and  of  reacting  with  phenylhy- 
drazin.  The  other  group,  on  the  contrary,  to  which  the  two 
maltoses  and  milk-sugar  belong,  the  members  act  like  monosac- 
charides in  regard  to  the  reduction  tests,  and  yield  osazones  with 
phenylhydrazin.  The  members  of  this  last  group  have  the  char- 
acter of  aldehyde-alcohols;  hence  they  are  given  the  following 
formula : 

/0-CH, 
CH,(OH).[CH(OH)J,.CH<  j 

\0— CH.[CH(0H)]3CH0. 

Cane-sugar  or  Saccharose  occurs  extensively  distributed  in 
the  plant  kingdom.  It  occurs  to  greatest  extent  in  the  stalk  of  the 
sugar-millet  and  sugar-cane,  the  roots  of  the  sugar-beet,  the  trunk 
of  certain  varieties  of  palms  and  maples,  in  carrots,  etc.  Cane-sugar 
is  of  extraordinarily  great  importance  as  a  food  and  condiment. 

Cane-sugar  forms  large,  colorless  monoclinic  crystals.  On  heat- 
ing it  melts  in  the  neighborhood  of  160°  C,  and  on  heating  stronger 
it  turns  brown,  forming  so-called  caramel.  It  dissolves  very  readily 
in  water,  and  according  to  Scheibler  '  100  parts  saturated  sugar 
solution  contains  67  parts  sugar  at  20°  C.     It  dissolves  with  diffi- 

'  See  Tollens'  Handbuch  der  Kohleliydrate,  S.  121. 


74  THE  CARB0HYBBATE8. 

culty  in  strong  alcohol.  Cane-sugar  is  strongly  dextrorotatory. 
The  specific  rotation  is  only  slightly  modified  by  concentration,  but 
is  markedly  changed  by  the  presence  of  other  inactive  snbstances. 
The  specific  rotation  is  {oc)D  =  +  66°. 5. 

Cane-sugar  acts  indifferently  towards  Moore's  test  and  to  the 
ordinary  reduction  tests,  and  it  does  not  react  with  phenylhydrazin. 
It  does  not  ferment  directly,  but  ferments  after  inversion,  which 
can  be  brought  about  by  an  enzym,  invertin,  contained  in  the 
yeast.  An  inversion  of  cane-sugar  also  takes  place  in  the  intestinal 
canal.  Concentrated  sulphuric  acid  blackens  cane-sugar  very 
quickly  even  at  the  ordinary  temperature,  and  anhydrous  oxalic 
acid  acts  the  same  on  warming  on  the  water-bath.  Various 
products  are  obtained  on  the  oxidation  of  cane-sugar,  dependent 
upon  the  variety  of  oxidizing  material  and  also  upon  the  intensity 
of  the  action.  Saccharic  acid  and  oxalic  acid  are  the  most  im- 
portant products. 

The  reader  is  referred  to  complete  text-books  on  chemistry  for 
the  preparation  and  quantitative  estimation  of  cane-sugar. 

Maltose  (malt-sugar)  is  formed  in  the  hydrolytic  cleavage  of 
starch  by  malt  diastase,  saliva,  and  pancreatic  juice.  It  is  obtained 
from  glycogen  under  the  same  conditions  (see  Chapter  VIII). 
Maltose  is  also  produced  transitorily  in  the  action  of  sulphuric  acid 
on  starch.  Maltose  forms  the  fermentable  sugar  of  the  potato  or 
grain  mash,  and  also  of  the  beerwort. 

Maltose  crystallizes  with  1  mol.  water  of  crystallization  in  fine 
white  needles.  It  is  readily  soluble  m  water,  rather  easily  in 
alcohol,  but  insoluble  in  ether.  Its  solutions  are  dextrorotatory, 
and  show  birotation.  The  specific  rotation  is  {oc)^)  =  -f  1.37°. 
Maltose  foments  readily  and  completely  with  yeast,  and  acts  like 
dextrose  in  regard  to  the  reduction  tests.  It  yields  phenj'lnialtosa- 
zone  on  warming  with  phenylhydrazin  for  1|-  hours.  This  phenyl - 
maltosazone  melts  at  206°  C.  Maltose  differs  from  dextrose  chiefly 
in  the  following:  It  does  not  dissolve  as  readily  in  alcohol,  has  a 
stronger  dextrorotatory  power,  has  a  feebler  reducing  action  on 
Fehling's  solution.  10  c.c.  Fehling's  solution  is,  according  to 
SoxHLET,'  reduced  by  77.8  millig^-ams  anhydrous  maltose  in 
approximately  Ifo  solution. 

Isomaltose.     This  variety  of  sugar  is  produced,  as  has  been 

1  Cit.  from  Tollens'  Handbuch,  S    152. 


STARCH.  75 

shown  by  Fischer,'  besides  dextrin-like  products,  by  the  action  of 
fuming  hydrochloric  acid  on  glucose.  It  is  also  formed,  besides 
ordinary  maltose,  in  the  action  of  diastase  on  starcli  paste.  It  is 
also  produced,  Avith  maltose,  by  the  action  of  saliva  or  pancreatic 
juice  (KuLZ  and  Vogel')  or  blood-serum  (Rohmann  ')  on  starch. 
It  also  occurs  in  beer  and  in  technical  starch-sugar. 

Isomaltose  dissolves  very  readily  in  water,  has  a  pronounced 
sweetish  taste,  ferments  but  slowly.  It  is  dextrorotatory,  and 
has  very  nearly  the  same  power  of  rotation  as  maltose.  Isomaltose 
is  characterized  by  its  osazone.  This  forms  fine  yellow  needles, 
which  begin  to  form  drops  at  140°  C.  and  melt  at  150-153°  C. 
It  is  rather  easily  soluble  in  hot  water. 

Milk-sugar  (lactose).  As  this  sugar  occurs  exclusively  in  the 
animal  world,  in  the  milk  of  human  beings  and  animals,  it  will  be 
treated  of  in  a  following  chapter  (on  milk). 

Trehalose  is  a  liexobiose  found  in  fungi.  Melebiose  is  a  saccharose  obtained 
with  d-fructose  in  the  partial  hydrolytic  cleavage  of  raflBnose  (a  hexotriose) 
occurring  in  beet-root  molasses,     Melebiose  splits  into  galactose  and  glucose. 

Polysaccliaricles. 

If  we  exclude  the  hexotrioses  and  the  few  remaining  sugar-like 
polysaccharides,  this  group  includes  a  great  number  of  very  complex 
carbohydrates,  which  occur  only  in  the  amorphous  condition  or  not 
as  crystals  in  the  ordinary  sense.  Contrary  to  the  bodies  belonging 
to  the  other  groups,  these  have  no  sweet  taste.  Some  are  soluble  m 
water,  while  others  swell  up  therein,  especially  in  warm  water,  and 
finally  are  neither  dissolved  nor  visibly  changed.  Polysaccharides 
are  ultimately  converted  into  monosaccharides  by  bydrolytic 
cleavage. 

The  polysaccharides  (not  sugar-like)  are  ordinarily  divided  into 
the  following  chief  groups:  starch  group.,  gum  and  vegetable-muci- 
lage group,  and  cellulose  group. 

Starch  Group  (C,H,„OJx. 

Starch,  Amylum  (CJI.  OJx.  This  substance  occurs  in  the 
plant  kingdom  very  extensively  distributed  in  the  different  parts  of 

'  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  23,  S.  3687. 

'  Zeitschr.  f    Biologic,  Bd.  31. 

3  Centralbl    f.  d.  med.  Wissensch.,  1893,  S.  849. 


T6  THE  GABB0HYDEATE8. 

the  plant,  especially  as  reserve  food  in  the  seeds,  roots,  tuhers,  and 
trunk. 

Starch  is  a  white,  odorless,  and  tasteless  powder,  consisting  of 
small  grains,  which  have  a  stratified  structure  and  different  shape 
and  size  in  different  plants.  According  to  the  ordinary  opinion 
the  starch-grains  consist  of  two  different  substances,  starch 
GEANULOSE  and  STAECH  CELLULOSE,  of  which  the  first  only  goes 
into  solution  on  treatment  with  diastatic  enzymes. 

Starch  is  considered  insoluble  in  cold  water.  The  grains  swell 
up  in  warm  water  and  burst,  yielding  a  paste.  Starch  is  insoluble 
in  alcohol  and  ether.  On  heating  starch  with  water  alone,  or 
heating  with  glycerin  to  190°  C,  or  on  treating  the  starch-grains 
with  6  parts  dilute  hydrochloric  acid  of  sp.  gr.  1.06  at  ordinary 
temjDerature  for  6  to  8  weeks,'  it  is  converted  into  soluble  starch 
(amylodextein",  amidulin).  Soluble  starch  is  also  formed  as  an 
intermediate  step  in  the  conversion  of  starch  into  dextrose  by  dilute 
acids  or  diastatic  enzymes.  Starch-granules  swell  up  and  form  a 
pasty  mass  in  caustic  potash  or  soda.  This  mass  gives  neither 
Mooee's  nor  Teommee's  test.  Starch-paste  does  not  ferment  with 
jeast.  The  most  characteristic  test  for  starch  is  the  blue  coloration 
produced  by  iodine  in  the  presence  of  hydroiodic  acid  or  alkali 
iodides.^  This  blue  coloration  disappears  on  the  addition  of  alcohol 
or  alkalies,  and  also  on  warming,  but  reappears  again  on  cooling. 

On  boiling  with  dilute  acids  starch  is  converted  into  glucose. 
In  the  conversion  by  means  of  diastatic  enzymes  we  have  as  a  rule, 
besides  dextrin,  maltose,  and  isomaltose,  only  very  little  glucose. 
We  are  considerably  in  the  dark  as  to  the  kind  and  number  of 
intermediate  products  produced  in  this  process  (see  dextrin). 

Starch  may  be  detected  by  means  of  the  microscope  and  by  the 
iodine  reaction.  Starch  is  quantitatively  estimated,  according  to 
Sachsse's  method,^  by  converting  it  into  sugar  by  hydrochloric 
acid  and  then  determining  the  sugar  by  the  ordinary  methods. 

Inulin,  (Cj.H,„OJx  +  H,0,  occurs  in  the  underground  parts  of 
many  compositse,  especially  in  the  roots  of  the  inula  helenium,  the 
tubers  of  the  dahlia,  the  varieties  of  helianthus,  etc.  It  is  ordi- 
narily obtained  from  the  tubers  of  the  dahlia. 

1  See  Tollens'  Ilandbucli,  S.  187. 

5  Mylius,  Ber.  d.  deutscL.  chem.  Gesellsch.,  Bd.  20,  S.  688,  and  Zeitsclir.  f. 
physiol.  Chem.,  Bd.  11. 

3  Tollens'  Handbucli,  S.  184. 


GUMS  AND    VEGETABLE  MUCILAGES.  77 

luuliu  forms  a  white  powder,  similar  to  starch,  consisting  of 
spheroid  crystals,  which  are  readily  soluble  in  warm  water  without 
forming  a  paste.  It  separates  slowly  on  cooling,  but  more  rapidly 
on  freezing.  Its  solutions  are  Isevogyrate  and  are  precipitated  by 
alcohol,  and  are  only  colored  yellow  with  iodine.  Inulin  is  con- 
verted into  the  la^vogyrate  monosaccharide  fructose,  on  boiling  with 
dilute  sulphuric  acid.  Diastatic  enzymes  have  no  or  very  slight 
action  on  inulin.' 

Lichenin  (moss-starch)  occurs  in  many  lichens,  namely,  in  Iceland  moss. 
It  is  not  soluble  in  cold  water,  but  swells  up  into  a  jelly.  It  is  soluble  in  hot 
water,  forming  a  jelly  on  allowing  the  concentrated  solution  to  cool.  It  is 
colored  yellow  by  iodine,  and  yields  glucose  on  boiling  with  dilute  acids. 
Lichenin  is  not  changed  by  diastatic  enzymes  such  as  ptyalin  or  amylopsin 
(NlLSON'^). 

Glycogen.  This  carbohydrate,  which  stands  to  a  certain  extent 
between  starch  and  dextrin,  is  principally  found  in  the  animal 
kingdom,  hence  it  will  be  treated  in  a  subsequent  chapter  (on  the 
liver). 

The  Gums  and  Vegetable  Mucilages  (C,H,„OJx. 

These  bodies  may  be  divided  into  two  chief  groups,  according  to 
their  origin  and  occurrence,  namely,  the  dextrin  group  and  the 
vegetable  gums  or  mucilages.  The  dextrines  stand  in  close  relation- 
ship to  the  starches  and  are  formed  therefrom  as  intermediate 
products  in  the  action  of  acids  and  diastatic  enzymes.  The  vari- 
ous kinds  of  vegetable  gums  and  vegetable  mucilages  occur,  on  the 
contrary,  as  natural  products  in  the  plant  kingdom,  and  some  may 
be  separated  from  certain  plants  as  amorphous,  transparent  masses 
and  others  may  be  extracted  from  certain  parts  of  the  plant,  such 
as  the  wood  and  seeds,  by  proper  solvents. 

The  dextrines  yield  as  final  products  only  hexoses,  and  indeed 
only  dextrose  on  complete  hydrolysis.  The  vegetable  gums  and 
the  mucilages  yield,  on  the  contrary,  not  only  hexoses,  but  also  an 
abundance  of  pentoses  (gum.  arable  and  wood-gum),  d-galactose 
occurs  often  amongst  the  hexoses,  and  as  differentiation  from  the 
dextrines  they  yield  mucic  acid  on  oxidation  with  nitric  acid.  The 
dextrines,  as  well  as  the  ordinary  varieties  of  gums  and  mucilages, 
are  precipitated  by  alcohol.  Basic  lead  acetate  precipitates  the 
gums  and  mucilages,  but  not  the  dextrins. 

'  Tollens'  Handbuch,  S.  203. 
'  Upsala  Lakaref   forh.,  Bd.  28. 


78  '  THE   CARBOHYDRATES. 

Dextrin  (British  gum)  is  produced  on  heating  starch  to  200- 
210°  C,  or  by  heating  starch,  which  has  previously  been  moistened 
with  water  containing  a  little  nitric  acid,  to  100-110°  C.  Dex- 
trins  are  also  produced  by  the  action  of  dilute  acids  and  diastatic 
enzymes  on  starch.  We  are  not  quite  clear  in  regard  to  the  steps 
takiug  place  in  the  above  processes,  but  the  ordinary  views  are  as 
follows :  Soluble  starch  is  the  first  product,  from  which  a  dextrin, 
erytlirodextnn,  which  is  colored  red  by  iodine,  and  sugar  are 
formed  by  hydrolytic  splitting.  On  further  splitting  of  this 
erythrodextrin  more  sugar  and  a  dextrin,  acJiroodextrin,  which  is 
not  colored  by  iodine,  is  formed.  From  this  achroodextrin  after 
successive  splittings  we  have  sugar  and  dextrins  of  lower  molecular 
weights  formed,  until  finally  we  haye  sugar  and  a  dextrin,  malto- 
dextrin,  which  refuses  to  split  further,  as  final  products.  The 
views  are  rather  contradictory  in  regard  to  the  number  of  dextrins 
which  occur  as  intermediate  steps.  The  sugar  formed  is  isomaltose, 
from  which  maltose  and  very  little  dextrose  are  produced.  Another 
view  is  that  first  several  dextrins  are  formed  consecutively  m  the 
successive  splitting  with  hydration,  and  then  finally  the  sugar  is 
formed  by  the  splitting  of  the  last  dextrin. ' 

The  various  dextrins  have  not  as  yet  been  separated  from  each 
other,  nor  isolated  as  chemical  individuals;  hence  the  characteristic 
properties  and  reactions  can  only  be  given  for  the  dextrins  in 
general. 

The  dextrins  appear  as  an  amorphous,  white  or  yellowish-white 
powder  which  is  readily  soluble  in  water.  Their  concentrated 
solutions  are  viscid  and  sticky,  similar  to  gum  solutions.  The 
dextrins  are  dextrogyrate,  the  specific  rotation  of  maltodextrin 
being  («r)D  =  +  174°. 5.  They  are  insoluble  or  nearly  so  in 
alcohol,  and  insoluble  in  ether.  Watery  solutions  of  dextrins  are 
not  precipitated  by  basic  lead  acetate.  Dextrins  dissolve  copper 
oxyhydrate  in  alkaline  liquids,  forming  a  beautiful  blue  solution. 
The  question  whether  or  not  perfectly  pure  dextrin  reduces 
Fehling's  solution  is  undecided.  According  to  Brucke'  a  non- 
reducible dextrin  may  be  obtained  by  warming  a  solution  of  achroo- 
dextrin  with   an   excess    of    alkaline   copper   solution    and    then 

'  In  regard  to  the  new  theories  see  Lintner  and  Dull,  Ber.  d.  deutsch.  chem. 
Gesellsch  ,  Bd.  26,  S,  2533,  and  Scheiblerand  Mittelmeier,  ibid.,  Bd.  23,  S.  3060, 
and  Bd   26.  S.  2930. 

2  Vorlesungen  liber  Physiologie.     Wien,  1874.     S.  231. 


CELLULOSE.  Y9 

precipitating  with  alcohol.  According  to  Scheiki.er  and  Mittel- 
meiek'  the  dextrin  obtained  by  the  action  of  acid  is  a  polysaccharide 
of  an  aldehydic  nature,  hence  it  acts  as  a  reducing  agent.  The 
dextrins  are  not  directly  fermentable.  The  behavior  of  the  various 
dextrins  to  iodine  has  been  given  above,  but  it  must  be  remarked 
that,  according  to  Musculus  and  Meter,'  erythrodextrin  is  only 
a  mixture  of  achroodextrin  with  a  little  soluble  starch. 

The  vegetable  gums  are  soluble  in  water,  forming  solutions  which 
are  viscid  but  may  be  filtered.  We  designate,  on  the  contrary,  as 
vegetable  mucilages  those  varieties  of  gum  which  do  not  or  only 
partly  dissolve  in  water,  and  which  sv.^ell  up  therein  to  a  greater  or 
less  extent.  The  natural  varieties  of  gum  and  mucilage  to  which 
several  generally  known  and  important  substances,  such  as  gum 
arable,  wood-gum,  cherry-gum,  salep  and  quince  mucilage,  and 
probably  also  the  little-studied  pectin  substances,  belong  will  not  be 
treated  of  in  detail,  because  of  their  unimportance  from  a  zoo- 
physiological  standpoint. 

The  Cellulose  Group  (C,H,„OJx. 

Cellulose  is  that  carbohydrate,  or  perhaps  more  correctly  mix- 
ture of  carbohydrates,  which  forms  the  chief  constituent  of  the  walls 
of  the  plant-cells.  This  is  true  for  at  least  the  walls  of  the  young 
cells,  while  in  the  walls  of  the  older  cells  the  cellulose  is  extensively 
incrusted  with  a  substance  called  ligxix. 

The  true  celluloses  are  characterized  by  their  great  insolubility. 
They  are  insoluble  in  cold  or  hot  water,  alcohol,  ether,  dilute  acids, 
and  alkalies.  "We  have  only  one  specific  solvent  for  cellulose,  and 
that  is  an  ammoniacal  solution  of  copjaer  oxide  called  Schweitzer's 
reagent.  The  cellulose  may  be  precipitated  from  this  solvent  by 
the  addition  of  acids,  and  obtained  as  an  amorphous  powder  after 
washing  with  water. 

Cellulose  is  converted  into  a  substance,  so-called  amyloid, 
which  gives  a  blue  coloration  with  iodine  by  the  action  of  concen- 
trated sulphuric  acid.  By  the  action  of  strong  nitric  acid  or  a 
mixture  of  nitric  acid  and  concentrated  sulphuric-acid  celluloses  is 
converted  into  nitric-acid  esters  or  nitro-cellulose,  which  are  highly 
explosive  and  have  found  great  practical  use. 

1  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  23,   S.  3060,  and  Bd.  26,  S.  2930. 
'  Zeitschr.  f.  physiol.  Chem.,  Bd.  4,  S.  451. 


80  THE  CARBOHYDRATES. 

The  ordinary  celluloses  when  treated  at  the  ordinary  tempera- 
ture with  strong  sulphuric  acid  and  then  boiled  for  some  time  after 
diluting  with  water  is  converted  into  dextrose.  Other  varieties 
of  cellnlose  have  a  different  behavior,  namely,  we  have  a  cellulose 
which  yields  mannose  on  the  preceding  treatment.  This  substance, 
called  mannoso-cellulose  by  E.  Schulze,'  occurs  in  the  coffee-bean, 
as  well  as  in  the  cocoannt  and  sesame  cake,  and  is  not  to  be  con- 
sidered as  belonging  to  the  hemicellulose  group. 

Hemicelluloses  are,  according  to  E.  Schulze,  those  constituents 
of  the  cell- wall  related  to  cellulose  which  differ  from  the  ordinary 
cellulose  by  dissolving  on  heating  with  strongly  diluted  mineral 
acids,  such  as  1.25^  sulphuric  acid,  with  a  splitting  into  monosac- 
charides. The  sugars  produced  hereby  are  of  different  kinds.  The 
hemicellulose  from  the  yellow  lupin  yields  galactose  and  arabinose, 
from  the  rye  and  wheat  bran  arabinose  and  xylose,  and  from  the 
ivory-nut — called  reserve  cellulose  by  Reiss  ' — mannose. 

The  cellulose,  at  least  in  part,  undergoes  decomposition  in  the 
intestinal  tract  of  man  and  animals.  A  closer  discussion  of  the 
nutritive  value  of  cellulose  will  be  given  in  a  future  chapter  (on 
digestion).  The  great  importance  of  the  carbohydrates  in  the 
animal  economy  and  to  animal  metabolism  will  also  be  given  in 
following  chapters. 

'Zeitschr.  f.  physiol.  Chem.,  Bd,  16. 
^Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  33. 


CHAPTEE   IV. 

THE   ANIMAL   FATS. 

The  fats  form  the  third  chief  group  of  the  organic  foods  of  man 
and  animals.  They  occur  very  widely  distributed  in  the  animal 
and  plant  kingdoms.  Fat  occurs  in  all  organs  and  tissues  of  the 
animal  organism,  though  the  quantity  may  be  so  variable  that  a 
tabular  exhibit  of  the  amount  of  fat  in  different  organs  is  of  little 
interest.  The  marrow  contains  the  largest  quantity,  having  over 
960  p.  m.  The  three  most  important  deposits  of  fat  in  the  animal 
organism  are  the  intermuscular  connective  tissue,  the  fatty  tissue 
in  the  abdominal  cavity,  and  the  subcutaneous  connective  tissues. 
Amongst  the  plants  the  seeds  and  fruit,  and  in  certain  instances  also 
the  roots,  are  rich  in  fat. 

The  fats  consist  nearly  entirely  of  so-called  neutral  fats  with 
only  very  small  quantities  of  fatty  acids.  The  neutral  fats  are 
esters  of  the  triatomic  alcohol,  glycerin,  with  monobasic  fatty  acids. 
These  esters  are  triglycerides,  that  is,  the  three  hydrogen  atoms  of 
the  hydroxyl  of  the  glycerin  are  replaced  by  the  fatty-acid  radicals, 
and  their  general  formula  is  therefore  CgH^.Og.Rj.  The  animal  fats 
consist  chiefly  of  esters  of  the  three  fatty  acids,  stearic,  palmitic, 
and  oleic  acids.  In  the  plant  kingdom  triglycerides  of  other  fatty 
acids,  such  as  lauric  acid,  linoleic  acid,  erucic  acid,  etc.,  sometimes 
occur  abundantly. 

The  animal  fats  are  of  the  greatest  interest  and  consist  of  a 
mixture  of  varying  quantities  of  tkistearin",  teipalmitin',  and 
TRIOLEIN,  having  an  average  elementary  composition  of  C  76.5, 
H  12.0,  and  0  11.5  per  cent. 

Fats  from  different  species  of  animals,  and  even  from  different 
parts  of  the  same  animal,  have  an  essentially  different  consistency, 
depending  upon  the  relative  amounts  of  the  different  fats.  In  solid 
fats — as  tallow — tristearin  and  tripalmitin  are  in  excess,  while  the 

81 


82  THE  ANIMAL  PATS. 

less  solid  fats  are  characterized  by  a  greater  abundance  of  tripal- 
mitin  and  triolein.  This  last-mentioned  fat  is  fonnd  in  greater 
quantities  proportionally  in  cold-blooded  animals,  and  this  accounts 
for  the  fat  of  these  animals  remaining  fluid  at  temperatures  at 
wliich  the  fat  of  warm-blooded  animals  solidifies.  Human  fat  from 
'diiferent  organs  and  tissues  contains,  in  round  numbers,  670-800 
p.  m.  triolein.  The  melting-point  of  different  fats  depends  upon 
the  composition  of  the  mixtures,  and  it  not  only  varies  for  fat  from 
different  tissues  of  the  same  animal,  but  also  for  the  fat  from  the 
.same  tissues  in  various  kinds  of  animals. 

Neutral  fats  are  colorless  or  yellowish  and,  when  perfectly  pure, 
odorless  and  tasteless.  They  are  lighter  than  water,  on  which  they 
float  when  in  a  molten  condition.  They  are  insoluble  in  water, 
dissolve  in  boiling  alcohol,  but  separate  on  cooling, — often  in 
crystals.  They  are  easily  soluble  in  ether,  benzol,  and  chloroform. 
The  fluid  neutral  fats  give  an  emulsion  when  shaken  with  a  solu- 
tion of  gum  or  albumin.  With  water  alone  they  give  an  emulsion 
only  after  vigorous  and  prolonged  shaking,  but  the  emulsion  is  not 
persistent.  The  presence  of  some  soap  causes  a  very  fine  and  per- 
manent emulsion  to  form  easily.  Fat  produces  spots  on  paper 
vhich  do  not  disappear;  it  is  not  volatile;  it  boils  at  about  300°  0. 
with  partial  decomposition,  and  burns  with  a  luminous  and  smoky 
flame.  The  fatty  acids  have  most  of  the  above-mentioned  proper- 
ties in  common  with  the  neutral  fats,  but  differ  from  them  in  being 
soluble  in  alcohol-ether,  in  having  an  acid  reaction,  and  by  not 
giving  the  acrolein  test.  The  neutral  fats  generate  a  strong  irritat- 
ing vapor  of  acrolein,  due  to  the  decomposition  of  glycerine, 
C3H^(OH)3  —  SH^O  —  CgH^O,  when  heated  alone,  or  more  easily 
when  heated  with  potassium  bisulphate  or  with  other  substances 
removing  water. 

The  neutral  fats  may  be  split  by  the  addition  of  the  constituents 
of  water  according  to  the  following  equation:  C3H^(OE)3  +  3H^0 
=  03X1^(011)3  +  3H0R.  This  splitting  may  be  produced  by  the 
pancreatic  enzyme  or  by  superheated  steam.  We  most  frequently 
decompose  the  neutral  fats  by  boiling  them  with  caustic  alkali  not 
too  concentrated,  or,  still  better  (in  zoochemical  researches),  with 
an  alcoholic  potash  solution.  By  this  procedure,  which  is  called 
saponification,  the  alkali  salts  of  the  fatty  acids  (soaps)  are  formed. 
If  the  saponification  is  made  with  lead  oxide,  then  lead-plaster, 
lead-salt  of  the  fatty  acids,  is  produced.     We  do  not  ouly  call  the 


STEARIN  AND  PALMITIN.  83 

splitting  of  neutral  fats  by  alkalies  saponification,  but  also  the 
splitting  of  neutral  fats  into  fatty  acids  and  glycerin  in  general. 

On  keeping  fats  for  a  long  time  in  contact  with  air  they  undergo 
a  change,  becoming  yellow  in  color,  acid  in  reaction,  and  develop  an 
unpleasant  odor  and  taste.  It  becomes  rancid^  and  in  this  change 
a  part  of  the  fat  is  split  into  fatty  acids  and  glycerin,  and  then  an 
oxidation  of  the  free  fatty  acids  takes  jilace,  producing  volatile 
bodies  of  an  unpleasant  odor.  The  rancidity  is  not  due,  as  shown 
by  Gaffky  and  Ritsert,'  to  the  presence  of  microbes.  According 
to  these  investigators  the  change  is  due  to  the  combined  action  of 
air  and  light. 

In  certain  animal  fats,  as  in  milk-fat,  small  quantities  of 
triglycerides  of  lower  fatty  acids,  such  as  butyric,  caproic  acids, 
etc.,  occur.  The  same  is  observed  in  fat  from  certain  animals, 
although  little  studied.  Still  these  are  of  minor  importance  as 
compared  to  the  three  most  important  fats  of  the  animal  bod}^, 
namely,  tristearin^  tripalmitin,  and  triolein. 

Stearin,  or  tristearin,  C3H^(C\^H3^0J„  occurs  especially  in 
the  solid  varieties  of  tallow,  but  also  in  the  vegetable  fats. 

Stearic  acid,  C,gH3gO„,  is  found  in  the  free  state  in  decomposed 
pus,  in  the  expectorations  in  gangrene  of  the  lungs,  and  in  cheesy 
tuberculous  masses.  It  occurs  as  lime-soap  in  excrements  and 
adipocere,  and  in  this  last  product  also  as  an  ammonia  soap.  It 
perhaps  exists  as  sodium  soap  in  the  blood,  transudations,  and  pus. 

Stearin  is  the  hardest  and  most  insoluble  of  the  three  ordinary 
neutral  fats.  It  is  nearly  insoluble  in  cold  alcohol  and  soluble  with 
great  difficulty  in  cold  ether  (225  parts).  It  separates  from  warm 
alcohol  on  cooling  as  rectangular,  less  frequently  as  rhombical 
plates.  The  statements  in  regard  to  the  melting-point  are  some- 
what varied.  Pure  stearin,  according  to  IIeintz,*  melts  between 
+  55°  and  71°. 5.  The  stearin  from  the  fatty  tissues  (not  pure) 
melts  at  +  63°  C. 

Stearic  acid  crystallizes  (on  cooling  from  boiling  alcohol)  in 
large,  shining,  long-rhombical  scales  or  plates.  It  is  less  soluble 
than  the  other  fatty  acids  and  melts  at  69.2°  C.  Its  barium  salt 
contains  19.49'^  barium. 

Palmitin,  tripalmitin,  C,H,(C,Jl3,0,)3.  Of  the  two  solid 
varieties  of  fats,  palmitin  is  the  one  which  occurs  in  predominant 

'  Naturwissenschaftl.  Woclienschr. ,  1890. 
'Aunal.  d.  Chem.  u.  Pharm  .  Bd.  93.  S.  300. 


84  THE  ANIMAL  FATS. 

quantities  in  human  fat  (Langer).'  Palmitin  is  present  in  all 
animal  fats  and  in  several  kinds  of  vegetable  fats.  A  mixture  of 
stearin  and  palmitin  was  formerly  called  MARGARiiT. 

Palmitic  acid,  Cj^Hj^O^.  As  to  occarrence,  about  the  same 
remarks  apply  as  to  stearic  acid.  The  mixture  of  these  two  acids 
has  been  called  margaric  acid,  and  this  mixture  occurs — often  as 
very  long,  thin,  crystalline  plates — in  old  pus,  in  expectorations  from 
gangrene  of  the  lungs,  etc. 

Palmitin  crystallizes,  on  cooling  from  a  warm  saturated  solution 
in  ether  or  alcohol,  in  starry  rosettes  of  fine  needles.  The  mix- 
ture of  palmitin  and  stearin,  called  margarin,  crystallizes,  on  cool- 
ing from  a  solution,  as  balls  or  roand  masses  which  consist  of  short 
or  long,  thin  plates  or  needles  which  often  appear  like  blades  of 
grass.  Palmitin,  like  stearin,  has  a  variable  melting  and  solidifying 
point,  depending  upon  the  way  it  has  been  previously  treated. 
The  melting-point  is  often  given  as  -{-  62°.  According  to  other 
statements"  it  melts  at  50°. 5  C,  solidifies  on  further  heat  and 
melts  again  at  66°. 50  C. 

Palmitic  acid  crystallizes  from  an  alcoholic  solution  in  tufts  of 
fine  needles.  It  melts  at  +  62°  C. ;  still  the  admixture  with  stearic 
acid,  as  Hein'tz  has  shown,  essentially  changes  the  melting  and 
solidifying  points  according  to  the  relative  amounts  of  the  two 
acids.  Palmitic  is  somewhat  more  soluble  in  cold  alcohol  than 
stearic  acid;  but  they  have  about  the  same  solubility  in  boiling 
alcohol,  ether,  chloroform,  and  benzol. 

Olein,  TEiOLEiN,  C3H^(C,jH330j3,  is  present  in  all  animal  fats 
and  in  greater  quantities  in  plant  fats.  It  is  a  solvent  for  stearin 
and  palmitin.  Oleic  acid,  elaic  acid,  CjJij^O,,  occurs  probably 
as  soaps  in  the  intestinal  canal  during  digestion  and  in  the  chyle. 

Olein  is,  at  ordinary  temperatures,  a  nearly  colorless  oil  of  a 
specific  gravity  of  0.914,  without  odor  or  marked  taste.  It  solidifies 
in  crystalline  needles  at  —  5°  C.  It  becomes  rancid  quickly  if 
exposed  to  the  air.  It  dissolves  with  difficulty  in  cold  alcohol,  but 
more  easily  in  warm  alcohol  or  in  ether.  It  is  converted  into  its 
isomer,  elaidin,  by  nitrous  acid. 

Oleic  acid  forms  at  ordinary  temperature  a  colorless,  tasteless, 
and  odorless  oily  liquid  which  solidifies  in  crystals  at  about  +  4°  C., 
which  then  melt  again  at  +  ^4"^  C.     On  being  heated  it  yields, 

'  MoDatshefte  C.  Chem. ,  Bd,  3. 

»U.  Beriedikl.  Analyse  der  Fette.     Berlin,  1886.     S,  29. 


DETECTION  OF  FATS.  85 

besides  volatMe  fatty  acids,  sebacic  acid,  C,„H,gO^,  which  crystal- 
lizes iu  shining  plates  and  melts  at  +  127°  C.  Oleic  acid  is  con- 
verted by  nitrous  acid  into  its  isomer,  elaidic  acid,  which  is  a 
solid,  melting  at  -|-  45°  C.  Oleic  acid  is  insoluble  in  water,  but 
dissolves  in  alcohol,  ether,  and  chloroform.  With  concentrated 
sulphuric  acid  and  some  cane-sugar  it  gives  a  beautiful  red  or 
reddish- violet  liquid  whose  color  is  similar  to  that  produced  in 
Pettenkofer's  test  for  bile-acids. 

If  the  watery  solution  of  the  alkali  combinations  of  oleic  acid  is 
precipitated  with  lead  acetate,  a  white,  tough,  sticky  mass  of  lead 
oleate  is  obtained  which  is  not  soluble  in  water  and  only  slightly  in 
alcohol,  but  is  soluble  in  ether  {differing  from  the  lead-salts  of  the 
other  two  fatty  acids). 

An  acid  related  to  oleic  acid,  doeglic  acid,  wbicli  is  solid  at  0°  C,  liquid 
at  -|-  16°,  and  soluble  iu  alcohol,  is  found  iu  the  blubber  of  the  Balama 
ro><trata.  Kurbatopp  '  has  demonstrated  the  presence  of  liuoleic  acid  in  the 
fat  of  the  silurus,  sturgeon,  seal,  and  certain  other  animals. 

To  detect  the  presence  of  fat  in  an  animal  fluid  or  tissue  the  fat 
must  first  be  extracted  with  ether.  After  the  evaporation  of  tiie 
ether  the  residue  is  tested  for  fat  and  the  acrolein  test  must  not  be 
neglected.  If  this  test  gives  positive  results,  then  neutral  fats  are 
present;  if  the  results  are  negative,  then  only  fatty  acids  are 
present.  If  the  above  residue  after  evaporation  gives  the  acrolein 
test,  then  a  small  portion  is  dissolved  in  alcohol-ether  free  from 
acid  and  which  has  been  colored  bluish  violet  by  tincture  of  alkanet. 
If  the  color  becomes  red,  a  mixture  of  neutral  fat  and  fatty  acids 
is  present.  In  this  case  the  fat  is  treated  in  the  warmth  with  a 
soda  solution  and  evaporated  on  the  water-bath,  constantly  stirring 
until  all  the  water  is  removed.  The  fatty  acids  hereby  combine 
with  the  alkali,  forming  soaps,  while  the  neutral  fats  are  not  saponi- 
fied under  these  conditions.  If  this  mixture  of  soaps  and  neutral 
fats  is  treated  with  water  and  then  shaken  with  pure  ether,  the 
neutral  fats  are  dissolved,  while  the  soaps  remain  in  the  watery 
solution.  The  fatty  acids  may  be  separated  from  this  solution  by 
the  addition  of  a  mineral  acid  which  sets  the  acid  free. 

The  neutral  fats  separated  from  the  soaps  by  mean  of  ether  are 
often  contaminated  with  cholesterin,  which  must  be  sej)arated  in 
quantitative  determinations  by  saponification  with  alcoholic  caustic 
potash.  The  cholesterin  is  not  attacked  by  the  caustic  alkali,  while 
the  neutral  fats  are  saponified.  After  the  evaporation  of  the 
alcohol  the  residue  is  dissolved  in  water  and  shaken  with  ether, 
which  dissolves  the  cholesterin.  The  fatty  acids  are  separated  from 
the  watery  solution  of  the  soaps  by  the  addition  of  a  mineral  acid. 
If  a  mixture  of  soaps,  neutral  fats,  and  fatty  acids  is  originally 

'Maly's  Jahresber.,  Bd.  23. 


86  THE  ANIMAL   FATS. 

present,  it  is  treated  first  with  water,  then  agitated  with  ether  free 
from  alcohol,  which  dissolves  the  fat  and  fatty  acids,  while  the 
soaps  remain  in  the  solution,  with  the  exception  of  a  very  small 
amount  which  is  dissolved  by  the  ether. 

To  detect  and  to  separate  the  different  varieties  of  neutral  fat& 
from  each  other  it  is  best  first  to  saponify  them  with  alcoholic 
potash,  or  still  better  with  sodium  alcoholate,  according  to  Kossel, 
OBERMiJLLER,  and  Krijger/  After  the  evaporation  of  the  alcohol 
they  are  dissolved  in  water  and  precipitated  with  sugar  of  lead. 
The  lead  oleate  is  then  separated  from  the  other  two  lead-salts  by 
repeated  extraction  with  ether.  The  residue  insoluble  in  ether  is 
decomposed  on  the  water-bath  with  an  excess  of  soda  solution, 
evaporated  to  dryness,  finely  pulverized,  and  extracted  with  boiling 
alcohol.  The  alcoholic  solution  is  then  fractionally  precipitated  by 
barium  acetate  or  barium  chloride.  In  one  fraction  the  amount  of 
barium  is  determined,  and  in  the  other  the  melting-point  of  the 
fatty  acid  set  free  by  a  mineral  acid.  The  fatty  acids  occurring 
originally  in  the  animal  tissues  or  fluids  as  free  acids  or  as  soaps  are 
converted  into  barium  salts  and  investigated  as  above. 

The  fats  are  poor  in  oxygen  but  rich  in  carbon  and  hydrogen. 
They  therefore  represent  a  large  amount  of  chemical  potential 
energy,  and  they  correspondingly  yield  large  quantities  of  heat  on 
combustion.  They  take  first  rank  amongst  the  foods  in  this  regard 
and  are  therefore  of  very  great  importance  in  animal  life.  We  will 
speak  more  in  detail  of  this  significance,  also  of  fat  formation  and 
the  behavior  of  the  fats  in  the  body,  in  the  following  chapters. 

The  LECiTHiisrs,  which  stand  in  close  relationship  to  the  fats, 
will  be  treated  of  in  a  subsequent  chapter.  The  following  bodies 
append  themselves  to  the  ordinary  animal  fats. 

Spermaceti.  In  the  living  spermaceti  or  white  whale  there  is  found  in  a 
large  cavity  in  the  skull  an  oily  liquid  called  spermaceti,  which  on  cooling 
after  death  separates  into  a  solid  crystalline  part,  ordinarily  called  spermaceti, 
and  into  a  liquid,  spermaceti- oil.  This  last  is  separated  by  pressure.  Sper- 
maceti is  also  found  in  other  whales  and  in  certain  species  of  dolphin. 

The  purified,  solid  spermaceti,  which  is  called  cetin,  is  a  mixture  of  esters 
of  fatty  acids.  The  chief  constituent  is  the  cetyl-palmitic  ester  mixed  with 
small  quantities  of  compound  ethers  of  lauric,  myrisitic,  and  stearic  acids  with 
radicals  of  the  alcohols,  lethal,  CjaHss.OH,  methal,  C14H29.OH,  and  stethal,- 
CsHsT.OH. 

Cetin  is  a  snow-white  mass  shining  like  mother-of-pearl,  crystallizing  in 
plates,  brittle,  fatty  to  the  touch,  and  which  has  a  varying  melting-point 
of -|-  30°  to  50°  C,  depending  upon  its  purity.  Cetin  is  insoluble  in  water,  but 
dissolves  easily  in  cold  ether  or  volatile  and  fatty  oils.  It  dissolves  in  boiling 
alcohol,  but  crystallizes  on  cooling.  It  is  saponified  with  diflBculty  by  a  solu- 
tion of  caustic  potash  in  water,  but  with  an  alcoholic  solution  it  saponifies 
readily  and  the  above-mentioned  alcohols  are  set  free. 

'Zeitschr.  f.  physiol.  Chem.,  Bdd.  14,  15,  and  16. 


ETIIAL  87 

Ethal,  or  cetyl  alcohol,  CieHsj.OH,  which  also  occurs  in  the  coccygeal 
gland  of  ducks  and  geese  (De  Jonge')  and  in  smaller  quantities  in  beeswax, 
forms  white,  transparent,  odorless,  and  tasteless  crystals  which  are  insoluble 
in  water  but  dissolve  easily  in  alcohol  and  ether.     Ethal  melts  at  49.5°  ('. 

Spermaceti-oil  yields  on  saponification  valerianic  acid,  small  amounts  of 
solid  fatty  acids,  and  physetoleic  acid.  This  acid  forms  colorless  and  odor- 
less, needle-shaped  crystals  which  easily  dissolve  in  alcohol  and  ether  and  melt 
at  +  34°  C. 

Beeswax  may  be  treated  here  as  concluding  the  subject  of  fats.  It  contains 
three  chief  constituents:  1  Cerotic  acid,  C27H6402,  which  occurs  as  cetyl 
ether  in  Chinese  wax  and  as  free  acid  in  ordinary  wax.  It  dissolves  in  boiling 
alcohol  and  separates  as  crystals  on  cooling.  The  cooled  alcoholic  extract  of 
wax  contains  (3)  cerolein,  which  is  probably  a  mixture  of  several  bodies,  and 
(3)  MYRISIN,  which  forms  the  chief  constituent  of  that  part  of  wax  which  is 
insoluble  in  warm  or  cold  alcohol.  Myrisin  consists  chiefly  of  palmitic-acid, 
ether  of  melissyl  (myricyl)  alcohol,  CsoHsi.OH.  This  alcohol  is  a  silky,  shining, 
crystalline  body  melting  at  -|-  85°  C. 

'  Zeitschr.  f.  physiol.  Chem.,  Bd.  3. 


CHAPTER  V. 

THE   ANIMAL   CELL. 

The  cell  is  the  unit  of  the  manifold,  variable  forms  of  the 
organism;  it  forms  the  simplest  physiological  apparatus,  and  as  such 
is  the  seat  of  chemical  processes.  It  is  generally  admitted  that  all 
chemical  processes  of  importance  do  not  take  place  in  the  animal 
fluids,  but  transpire  in  the  cells,  which  may  be  considered  as  the 
chemical  laboratory  of  the  organism.  It  is  also  principally  the  cells 
which,  through  their  greater  or  less  activity,  regulate  or  govern  the 
range  of  the  chemical  processes  and  also  the  intensity  of  the  total 
exchange  of  material. 

It  is  natural  that  the  chemical  investigation  of  the  animal  cell 
should  in  most  cases  coincide  with  the  study  of  those  tissues  of 
which  it  forms  the  chief  constituent.  Only  in  a  few  cases  can  the 
cells  be  directly,  by  relatively  simple  manipulations,  isolated  in  a 
rather  pure  state  from  the  tissues,  as,  for  example,  in  the  investi- 
gation of  pus  or  of  tissue  very  rich  in  cells.  But  even  in  these 
cases  the  chemical  investigation  may  not  lead  to  any  positive  results 
in  regard  to  the  constituents  of  the  uninjured  living  cells.  By  the 
process  of  chemical  transformation  new  substances  may  be  formed 
on  the  death  of  the  cell,  and  at  the  same  time  physiological  con- 
;stituents  of  the  cell  may  be  destroyed  or  transported  into  the  sur- 
rounding menstruum  and  therefore  escape  investigation.  For  this 
and  other  reasons  we  possess  only  a  very  limited  knowledge  of  the 
constituents  and  the  composition  of  the  cell,  especially  of  the  living 
one. 

While  young  cells  of  different  origin  in  the  early  period  of  their 
existence  may  show  a  certain  similarity  in  regard  to  form  and 
chemical  composition,  they  may,  on  further  development,  not  only 
take  the  most  varied  forms,  but  may  also  offer  from  a  chemical 
standpoint  the  greatest  diversity.     As  a  description  of  the  constit- 


PROTOPLASM.  89 

ueats  and  composition  of  the  different  cells  occurring  in  the  animal 
organism  is  nearly  equivalent  to  a  demonstration  of  the  chemical 
properties  of  most  animal  tissues,  and  as  this  exposition  will  be 
found  in  their  respective  chapters,  we  will  here  only  discuss  the 
chemical  constituents  of  the  young  cells  or  the  cells  in  general. 

In  the  study  of  these  constituents  we  are  confronted  with 
another  difficulty,  namely,  we  must  differentiate  by  chemical 
research  between  those  constituents  which  are  essentially  necessary 
for  the  life  of  the  cells  and  those  which  are  casual,  i.e.,  stored  up 
as  reserve  material  or  as  metabolic  products.  In  this  connection 
we  have  only  been  able,  thus  far,  to  learn  of  certain  substances 
which  seem  to  occur  in  every  developing  cell.  Such  bodies,  called 
PRIMARY  by  KossEL,'  are,  besides  water  and  certain  mineral  con- 
stituents, proteids,  nucleoproteids  or  nuclein,  lecithins,  glycogen  (?), 
and  cholesterin.  Those  bodies  which  do  not  occur  in  every 
developing  cell  are  called  secondary.  Amongst  these  we  iiave 
fat,  glycogen  (?),  pigments,  etc.  It  must  not  be  forgotten  that  it 
is  still  possible  that  other  primary  cell  constituents  may  exist,  but 
unknown  to  us,  and  we  also  do  not  known  whether  all  the  primary 
constituents  of  the  cell  are  necessary  or  essential  for  the  life  and 
functions  of  the  same.  We  do  not  know,  for  example,  whether 
the  ever-present  cholesterin  is  an  excretory  product  of  the  meta- 
bolism within  the  cell  or  whether  it  is  necessary  for  the  life  and 
development  of  the  same. 

Another  important  question  is  the  division  of  the  various  cell 
constituents  between  the  two  morphological  components  of  the  cell, 
namely,  the  protoplasm  and  the  nucleus.  This  is  very  difficult  to 
decide  for  many  of  the  constituents,  nevertheless  it  is  appropriate 
to  differentiate  between  the  protoplasm  and  the  nucleus. 

The  Protoplasm  of  the  developing  cell  consists  during  life  of  a 
semi-solid  mass,  contractile  under  certain  conditions  and  readily 
changeable,  which  is  rich  in  water  and  whose  chief  portion  consists 
of  protein  substances.  If  the  cell  be  deprived  of  the  physiological 
conditions  of  life,  or  if  exposed  to  destructive  exterior  influences, 
such  as  the  action  of  high  temperatures,  of  chemical  agents,  or 
indeed  of  distilled  water,  the  protoplasm  dies.  The  albuminous 
bodies  which  it  contains  coagulate  at  least  partially,  and  other 
chemical  changes  are  found  to  take  place.     The  alkaline  reaction 

'  Verhandl.  der  physiol.  Gesellsch.  zu  Berlin,  1890-91,  Nos.  5  and  6. 


90  THE  ANIMAL   CELL. 

of  the  living  cell  may  be  converted  into  an  acid  by  the  appearance 
of  paralactic  acid,  and  the  carbohydrate,  glycogen,  which  habitually 
occurs  in  the  young  generative  cell  may  after  its  death  be  quickly 
changed  and  consumed. 

The  question  as  to  the  structure  of  the  jDrotoplasm  has  been 
answered  in  various  ways.  According  to  the  ordinary  view  the 
body  of  the  cell,  the  cytoplasm,  contains  a  network,  the  spoifGio- 
PLASM,  in  the  meshes  of  which  is  a  more  homogeneous,  structureless 
substance,  hyaloplasm.  It  has  also  been  admitted  that  the 
spongioplasm  consists  of  a  special  substance,  plasfin,  which  will  be 
described  later,  and  that  the  hyaloplasm  consists  chiefly  of  proteid. 
Besides  this  the  protoplasm  contains  granules  of  various  kinds 
which  behave  differently  with  dyes  and  sometimes  vacuoles  contain- 
ing fluid. 

The  proteids  of  the  jjrotoplasm  consist,  according  to  the  general 
view,  chiefly  of  glolulins.  Alhumins  have  also  been  found  besides 
the  globulins.  There  is  no  doubt  at  present  that  the  albumins 
occur  in  the  cells  only  as  traces,  or  at  least  only  in  trifling  quanti- 
ties. The  presence  of  globulins  can  hardly  be  disputed,  althongh 
certain  cell  constituents  described  as  globulins  have  been  shown  on 
closer  investigation  to  be  nucleoalbumins  or  nucleoproteids.  This 
is  true  for  the  so-called  /^-globulin  isolated  from  the  lymphatic 
glands  by  Halliburton.  On  the  contrary,  according  to  this 
investigator,  the  so-called  <x-cell  globulin,  coagulating  at  47-50° 
C,  and  occurring  in  all  cells,  is  a  true  globulin.' 

In  opposition  to  the  view  that  the  chief  mass  of  the  animal 
cell  consists  of  true  proteids,  the  author'  expressed  the  opinion 
several  years  ago,  that  the  chief  mass  of  the  protein  substances  of 
the  cells  does  not  consist  of  proteids  in  the  ordinary  sense,  but  con- 
sists of  more  complex  phosphorized  bodies,  and  that  the  globulins 
and  albumins  are  to  be  considered  as  nutritive  material  for  the  cells 
or  as  destructive  products  in  the  chemical  transformation  of  the 
protoplasm.  This  view  has  received  substantial  support  by  inves- 
tigations within  the  last  few  years.  Alex.  Schmidt  '  has  come  to 
the  view,  by  investigations  on  various  kinds  of  cells,  that  they 
contain  only  very  little  proteid,  and  that  the  chief  mass  consists  of 

1  See  Halliburton.  On  the  Chemical  Physiology  of  the  Animal  Cell,  1893, 
No,  1,  King's  College  Physiol.  Laboratory. 

2  Pfiiiger's  Arch.,  Bd.  36,  S.  449. 

2  Alex.  Schmidt,  Zur  Blutlehre,  Leipzig.     1893. 


PROTEIN  SUBSTANCES   OF  THE  CELLS.  91 

very  complex  protein  substances.  Lilienfeld  has  also  found  on  a 
quantitative  analysis  of  leucocytes  from  the  thymus  gland  only 
1.76^  proteid  (in  the  dried  substance),  in  the  ordinary  sense. 

Tlie  protein  substances  of  the  cells  consist  chiefly  of  compound 
woteids^  and  these  are  divided  between  the  glycoproteid  and  the 
nticleo-proteid  groups.  It  is  impossible  at  present  to  state  the 
extent  of  nucleoalbumins  in  the  cells  because  thus  far  in  most  cases 
no  exact  dilference  has  been  made  between  them  and  the  nucleo- 
proteids.  Hoppe-Seyler  '  calls  vitellin  a  regular  constituent  of  all 
protoplasm.  This  body  used  to  be  considered  as  a  globulin,  but 
later  researches  have  shown  that  the  so-called  vitelline  bodies  may 
be  of  various  kinds.  Certain  vitellins  seem  to  be  nucleoalbumins, 
and  it  is  therefore  very  probable  that  cells  habitually  contain 
nucleoalbumins. 

The  nucleoproteids  take  a  very  prominent  place  among  the  com- 
pound proteids  of  the  cell.  The  various  substances  isolated  by 
different  investigators  from  animal  cells,  such  as  tissue  fibj'mogen 
(WooLDRiDGE^),  cytoglohiu  2kTiA. preglobulin  (Alex.  Schmidt^),  or 
niicleohiston  (Kossel  and  Lilienfeld  ^),  belong  to  this  group. 
The  cell  constituent  which  swells  up  to  a  sticky  mass  with  common 
salt  solution  and  called  Rovida's  hycdine  substance.,  also  belongs  to 
this  group. 

The  above-mentioned  different  protein  substances  have  only 
been  simply  designated  as  constituents  of  the  cells.  The  next 
question  is  which  of  these  belong  to  the  protoplasm  and  which  to 
the  nucleus.  At  present  we  can  give  no  positive  answer  to  this 
question.  According  to  Kossel  and  Lilienfeld,^  the  cell  nucleus 
of  the  leucocytes  contains  a  nucleoproteid,  besides  nncleins,  as  chief 
constituent,  and  sometimes  perhaps  also  nucleic  acid  (see  below), 
while  the  body  of  the  cells  contains  chiefly  pure  proteids  besides 
other  substances,  and  only  a  little  nucleoalbumin,  containing  a  very 
small  quantity  of  phosphorus.  This  view  coincides  well  with  the 
observations  of  Lilienfeld  on  the  behavior  of  the  protoplasm  and 
cell  nucleus  on  one  side  as  compared  with  the  proteids  and  nuclein 

I  Physiol.  Chem.,  1877-1881,  S.  76. 

'  Die  Geriunung  des  Blutes.     Leipzig,  1891. 

*  Zur  Blutlehre. 

*  Lilienfeld,  Zeitschr.  f.  physiol.  Chem.,  Bd.  18. 

*  Ueber  die  Wahlverwandschaft  der  Zellelemente  zu  gewissen  Farbstoffen. 
Verhandl.  d.  physiol.  Gesellsch.  zu  Berlin,  No.  11,  1893. 


92  THE  ANIMAL   CELL. 

substances  with  certain  coloring  matters ;  but  it  seems  to  be 
inconsistent  with  the  quantitative  composition  of  the  leucocytes  as 
found  by  Lilienfeld.  If  we  admit,  according  to  Kossel  and 
LiLiE^sTFELD,  that  the  nucleoproteid,  called  by  them  nucleohiston^ 
belongs  only  to  the  nucleus  of  the  leucocytes  of  the  thymus  gland, 
then  77.45  parts  of  the  79.21  parts  of  proteins  in  100  parts  of  the 
dried  substance* belongs  to  the  nucleus  and  only  1.76  parts  to  the 
protoplasm.  As  the  lymphocytes  of  the  thymus  gland  of  the  calf 
contain  only  one  nucleus,  in  which  the  mass  of  the  nucleus  sur- 
passes that  of  the  cytoplasm,  it  is  natural  that  the  relative  propor- 
tion of  the  various  protein  substances  in  these  cells  cannot  be  taken 
as  a  standard  for  the  composition  of  other  cells  richer  in  cytoplasm. 

Complete  investigations  in  regard  to  the  distribution  of  protein 
substances  in  the  protoplasm  and  nucleus  of  other  cells  have  not 
been  made.  If  we  consider  for  the  present  that  the  cells  rich  in 
protoplasm  contain,  as  a  rule,  only  very  little  true  proteid,  we  are 
hardly  wrong  in  considering  it  probable  that  the  protoplasm  con- 
tains chiefly  nucleoalbumins  and  compound  proteids  besides  traces 
of  albumin  and  a  little  globulin.  These  compound  proteids  are  in 
certain  cases  glycoproteids,  but  otherwise  nucleoproteids  which 
differ  from  the  nucleoproteids  of  the  nucleus  in  being  poorer  in 
phosphorus,  besides  containing  a  great  deal  of  proteid  and  only  less 
of  the  prostetic  group,  and  hence  have  no  specially  pronounced  acid 
character. 

The  nucleoproteids  of  the  nucleus  are  on  the  contrary,  as  shown 
by  LiLiENFELD  and  Kossel,  rich  in  phosphorus  and  of  a  strongly 
a,cid  character.  These  nucleoproteids  will  be  treated  of  in  speaking 
of  the  nucleins  of  the  nucleus. 

In  cases  in  which  the  protoplasm  is  surrounded  by  an  outer, 
condensed  layer  or  a  cell  membrane,  this  envelope  seems  to  consist 
of  albumoid  substances.  In  a  few  cases  these  substances  seem  to 
be  closely  related  to  elastin;  in  other  cases,  on  the  contrary,  they 
seem  rather  to  belong  to  the  keratin  group.  The  chemical 
processes  by  which  these  albumoid  substances  are  formed  from  the 
albuminous  bodies  or  compound  proteids  of  the  protoplasm  are 
unknown. 

Among  the  non-proteid  substances  of  the  cell  we  must  first  men- 
tion lecithin,  which  exists  as  a  positive  constituent  of  the  proto- 
plasm.    It  is  difficult  to  say  whether  it  also  exists  in  the  nucleus. 


LECITHIN.  93 

Lecithin.  This  body  is,  according  to  the  investigations  of 
Stkecker,'  Huxdeshagen,'  and  Gilson,'  an  ether-like  combina- 
tion of  glycerophosphoric  acid  substituted  by  two  fatty  acid  radicals, 
with  a  base,  cholin.  Therefore  there  may  be  different  lecithins 
according  to  the  fatty  acid  contained  in  the  lecithin  molecule. 
One  of  these — distearyllecithin — has  been  closely  studied  by  Hoppe- 
Seyler  and  Diacoxow  :* 

0,A,XPO,  =  HO.(CH3)3KaH,0(OH)PO.O.C^H,  :  (C„H3,0J,. 

In  agreement  with  this,  if  lecithin  be  boiled  with  baryta- water 
it  yields  fatty  acids,  glycerophosphoric  acid,  and  cholin.  It  is  only 
slowly  decomposed  by  dilute  acids.  Besides  small  quantities  of 
glycerophosphoric  acid  (perhaps  also  distearylglycerophosphoric 
acid)  we  have  large  quantities  of  free  phosphoric  acid  split  off. 

Glycerophosphoric  acid  (H0)^P0.0.C3H^(0H),  is  a  bibasic 
acid,  which  probably  only  occurs  in  the  animal  fluids  and  tissues 
as  splitting  product  of  lecithin.  The  cholin,  which  is  identical 
with  the  bases  siistkalix  (in  mustard-seed)  and  amanitin  (in 
agaricus  muscarius),  has  the  formula  HO.!N'(CH3)3.C5H^.OH,  and  is 
therefore  considered  as  trimethylethoxylium  hydrate.  Cholin,  on 
the  contrary,  is  not  identical  with  the  base,  NEURiJf,  prepared  by 
LiEBREiCH  as  a  decomposition  product  from  the  brain,  which  is 
considered  as  trimethylvinylium  hydrate,  HO. N (€113)3.02113.  The 
combination  of  cholin  with  hydrochloric  acid  gives  with  platinum 
chloride  a  crystalline  double  combination  which  is  easily  soluble  in 
water,  insoluble  in  alcohol  and  ether,  and  which  crystallizes  in  six- 
sided  orange-colored  plates.  This  combination  is  used  in  detecting 
this  base. 

Lecithin  occurs,  as  Hoppe-Seyler'  has  especially  shown, 
widely  diffused  in  the  vegetable  and  animal  kingdoms.  According 
to  this  investigator,  it  occurs  also  in  many  cases  in  loose  combina- 
tion with  other  bodies,  such  as  albuminous  bodies,  haemoglobin,  and 
others.  Lecithin,  according  to  Hoppe-Seyler,  is  found  in  nearly 
all  animal  and  vegetable  cells  thus  far  studied,  and  also  in  nearly 
all  animal  fluids.     It  is  specially  abundant  in  the  brain,  nerves, 

'  Annal.  d.  Chem.  u.  Pharm.,  Bd.  148. 

»  Journ.  f.  prakt.  Chem.,  Bd.  28. 

^  Zeitschr.  f.  pliysiol.  Chem.,  Bd.  13. 

*  Hoppe-Seyler's  Med.  chem.  Untersuch.,  S.  231  and  405. 

« Physiol.  Chem.,  1877-1881,  p.  57. 


94  THE  ANIMAL    CELL. 

fish-eggs,  yolk  of  tlie  Qgg,  electrical  organs  of  the  Torpedo  electricus, 
semen  and  pns,  and  also  in  the  muscles  and  blood-corpuscles,  blood- 
plasma,  lymph,  milk,  and  bile,  as  well  as  in  other  animal  juices  and 
liquids.     Lecithin  is  also  found  in  pathological  tissues  or  liquids. 

Lecithin  may  be  obtained  in  grains  or  warty  masses  composed 
of  small  crystalline  plates  by  strongly  cooling  its  solution  in  strong 
alcohol.  In  the  dry  state  it  has  a  waxy  appearance,  is  plastic  and 
soluble  in  alcohol,  especially  on  heating  (to  40-50°  C.) ;  it  is  less 
soluble  in  ether.  It  is  dissolved  also  by  chloroform,  carbon  disul- 
phide,  benzol,  and  fatty  oils.  It  swells  in  water  to  a  pasty  mass 
Avhich  shows  under  the  microscope  slimy,  oily  drops  and  threads, 
so-called  myelin  forms  (see  Chapter  XII).  On  warming  this  swollen 
mass  or  the  concentrated  alcoholic  solution,  decomposition  takes 
place  with  the  production  of  a  brown  color.  On  allowing  the  solu- 
tion or  the  swollen  mass  to  stand,  decomposition  takes  place  and 
the  reaction  becomes  acid.  In  putrefaction  lecithin  yields  glycero- 
phosphoric  acid  and  cholin;  the  latter  further  decomposes  with  the 
formation  of  methylamin,  ammonia,  carbon  dioxide,  and  marsh-gas 
(Hasebkoek  ').  If  dry  lecithin  be  heated  it  decomposes,  takes  fire 
and  burns,  leaving  a  phosphorized  coke.  On  fusing  with  caustic 
alkali  and  saltpetre  it  yields  alkali  phosphates.  Lecithin  is  easily 
carried  down  during  the  precipitation  of  other  compounds  such  as 
the  proteid  bodies,  and  may  therefore  very  greatly-  change  the 
solubilities  of  the  latter. 

Lecithin  combines  with  acids  and  bases.  The  combination  with 
hydrochloric  acid  gives  with  platinum  chloride  a  double  salt  which 
is  insoluble  in  alcohol,  soluble  in  ether,  and  which  contains  10.2^ 
platinum. 

It  may  be  prepared  tolerably  pure  from  the  yolk  of  the  hen's 
egg  by  the  following  methods,  as  suggested  by  Hoppe-Seyler  and 
DiACONOW.^  The  yolk,  deprived  of  albumin,  is  extracted  with 
cold  ether  until  all  the  yellow  color  is  removed.  Then  the  residue 
is  extracted  with  alcohol  at  50-60°  C.  After  the  evaporation  of 
the  alcoholic  extract  at  50-60°  C,  the  sirupy  matter  is  treated 
with  ether  and  the  insoluble  residue  dissolved  in  as  little  alcohol  as 
possible.  On  cooling  this  filtered  alcoholic  solution  to  —  5°  to 
—  10°  C.  the  lecithin  gradually  separates  in  small  granules.  The 
etiier,  however,  contains  considerable  of  the  lecithin.     The  ether  is 

»Zeitschr.  f,  physiol.  Cbem.,  Bd.  12. 
*Hoppe  Seyler's  Med.-cliem.  Untersuch. 


PREPARATIOX   OF  LECITHIN.  95 

distilled  olf  and  the  residue  dissolved  in  chloroform  and  the  lecitliin 
precipitated  from  this  solution  by  means  of  acetou  (Altmanx  '). 

According  to  Gilsox,  a  new  portion  of  lecithin  may  be  obtained 
from  the  ether  used  in  extracting  the  yolk  by  dissolving  the  residue 
after  the  evaporation  of  the  ether  in  petroleum  ether  and  then 
shaking  this  solution  with  alcohol.  The  petroleum  ether  takes  the 
fat,  while  the  lecithin  remains  dissolved  in  the  alcohol  and  may  be 
obtained  therefrom  rather  easily  by  using  the  proper  precautions. 

The  detection  and  the  quantitative  estimatioa  of  lecithin  in 
animal  fluids  or  tissues  is  based  on  the  solubility  of  the  lecithin  (at 
50-60°  C.)  in  alcohol-ether,  by  which  the  phosphoric  acid  or 
glycerophosphoric  acid  salts  which  may  be  present  at  the  same  time 
are  not  dissolved.  The  alcohol-ether  extract  is  evaporated,  the 
residue  dried  and  fused  with  soda  and  saltpetre.  Phosphoric  acid 
is  formed  from  the  lecithin,  and  it  can  be  used  in  the  detection  and 
quantitative  estimation.  The  distearyllecithin  yields  S.TOS/'^  ^fif,- 
This  method  is,  however,  not  exactly  correct,  for  it  is  possible  that 
other  phosphorized  organic  combinations,  such  as  jecorin  (see 
Chapter  VIII)  and  j^rotagon  (Chapter  XII)  may  have  passed  into 
the  alcohol-ether  extract.  The  residue  of  the  evaporated  alcohol- 
ether  extract  may  be  boiled  for  an  hour  with  baryta-water,  filtered, 
the  excess  of  barium  precipitated  with  C0„,  and  filtered  while  hot. 
The  filtrate  is  concentrated  to  a  sirupy  consistency,  extracted  with 
absolute  alcohol,  and  the  filtrate  precipitated  with  an  alcoholic 
solution  of  platinum  chloride.  The  precipitate  after  filtration  may 
be  dissolved  in  water  and  allowed  to  crystallize  over  sulphuric  acid. 

Frofagons,  which  are  found  in  the  leucocytes  and  jjus  cells,  are 
also  to  be  considered  as  a  constituent  of  protoplasm.  These  phos- 
phorized bodies  occur  principally  in  the  brain  and  nerves  and  hence 
will  be  described  in  a  following  chapter. 

Glycogen^  discovered  by  Cl.  Bekxard  and  Hensix,  is  found 
in  developing  animal  cells  and  especially  in  developed  embryonic 
tissues.  According  to  Hoppe-Seyler  it  seems  to  be  a  never-failing 
constituent  of  the  cells,  which  show  amoeboidal  movement,  and  he 
found  this  carbohydrate  in  the  leucocytes,  but  not  in  the  developed 
motionless  pus-corpuscles. 

Salomox  and  afterwards  others  have,  however,  found  glycogen 
in  pus.'  From  the  relationship  which  seems  to  exist  between  glyco- 
gen and  muscular  work  (see  Chapter  XI),  it  is  presumable  that  a 
consumption  of  glycogen  takes  place  in  the  movement  of  animal  pro- 
toplasm. On  the  other  hand,  the  extensive  occurrence  of  glycogen 
in  embryonic  tissues,  as  also  its  occurrence  in  pathological  tumors 

'Cited  from  Hoppe-Seyler's  Handbuch,  etc.,  6.  Aufl.,  S,  84. 
'  In  regard  to  the  literature  on  glycogen  see  Chap,  VIII. 


96  TEE  ANIMAL   CELL. 

and  in  abundant  cell-formation,  speaks  for  the  importance  of  this 
body  in  the  formation  and  development  of  the  cell. 

In  adnlt  animals  glycogen  occurs  in  the  muscles  and  certain 
other  organs,  but  principally  in  the  liver;  therefore  it  will  be  com- 
pletely described  in  connection  with  this  organ  (Chapter  VIII).- 
Glycogen  has  been  directly  detected  as  a  constituent  of  the  proto- 
plasm of  various  cells. 

Another  body,  or  perhaps  more  correctly  a  group  of  bodies 
which  occur  widely  distributed  in  the  animal  and  vegetable  king- 
doms, and  which  occur  regularly  in  the  cells,  are  the  cholesterins. 
The  best-known  representative  of  this  group  is  ordinary  cholesterin,' 
which  is  the  chief  constituent  of  certain  biliary  calculi  and  exists  in 
abundant  quantities  in  the  brain  and  nerves.  It  is  hardly  admissi- 
ble that  this  body  is  of  direct  importance  for  the  life  and  develop- 
ment of  the  cell.  It  must  be  considered  that  the  cholesterin,  as 
accepted  by  Hoppe-Seyleh,"  is  a  cleavage  product  appearing  in  the 
cell  during  the  processes  of  life.  According  to  Hoppe-Seyler  the 
same  is  true  for  the  fats,  which  do  not  occur  constantly  in  the  cells 
and  have  nothing  to  do  in  the  ordinary  processes  of  life.  There  is 
no  doubt  that  cholesterin  exists  as  a  constituent  of  the  protoplasm, 
but  its  existence  in  the  nucleus  is  questionable. 

The  cell  nucleus  has  a  rather  complex  structure.  It  consists  in 
part  of  a  mitoplasni,  which  consists  of  fibriles  which  form  a  net- 
work, and  another  part,  which  is  less  solid  and  homogeneous, 
called  the  hyaloplasm.  The  mitoplasm  differs  from  the  hyaloplasm 
in  a  stronger  affinity  for  many  dyes.  On  account  of  this  behavior 
the  first  is  called  the  chromatic  substance  or  chromatin,  and  the 
other  the  achromatic  substance  or  ackromatin. 

The  hyaloplasm  of  the  nucleus  is  considered  as  a  mixture  of 
proteids.  The  mitoplasm  seems  to  contain  the  more  specific  con- 
stituent of  the  nucleus,  na,mely,  the  nuclein  substances.  Besides 
this  it  is  alleged  to  also  contain  another  substance,  plashn.  This 
last  is  less  soluble  than  the  nuclein  substances  and  does  not  have 
the  property,  like  them,  of  fixing  dyes. 

The  chief  constituents  of  the  cell  nucleus  are  the  nuclems,  the 
nudeoproteids,  and  in  a  few  cases  nucleic  acid. 

Nucleins.  By  the  name  nuclein  Hoppe-Seyler  and  Mie- 
SCHER  ^    designated  the  chief  constituent  of   the  nucleus  of  the 

'  See  Chap.  VIII. 

'Physiol.  Chem.,  S.  81. 

'Hoppe-Seyler,  Med. -chem.  Untersuch.,  S.  453. 


NUCLEINS  AND  PSEUDONUCLEINS.  97 

pus  cell  first  isolated  by  them.  Since  it  has  been  shown  by 
repeated  research  that  similar  bodies  occur  extensively  in  the  animal 
and  plant  kingdoms,  especially  in  organs  rich  in  cells,  we  have  for 
some  time  designated  as  nucleins  a  number  of  phosphorized  bodies 
which  are  in  part  derived  as  cleavage  j^roducts  from  the  nucleo- 
albumins  and  in  part  form  the  chief  constituent  of  the  cell  nucleus. 

According  to  IIoppe-Seyler,  these  bodies  may  be  divided  into 
three  groups.  The  first,  to  which  belongs  the  nuclein  of  yeast,  pus, 
nucleated  red  blood-corpuscles,  and  probably  of  the  cell  nucleus  in 
general,  yield  as  splitting  products,  on  boiling  with  acids,  pro- 
teid  bodies,  xanthin  bases,  and  phosphoric  acid.  To  the  second 
group,  which  yield  as  splitting  products  proteid  and  phosphoric 
acid,  belongs  the  nuclein  of  the  yolk  of  the  egg  and  casein — in 
other  words,  the  nucleo-albumins  in  general;  and  to  the  third 
group,  which  gives  as  splitting  products  only  phosphoric  acid 
and  xanthin  bases,  belongs  only  the  nuclein  of  the  sperm  of  th:; 
salmon. 

Those  nuclein  substances  which  do  not  yield  nuclein  bases  on 
splitting — such,  for  instance,  as  nuclein  from  casein  and  vitellin — are 
to  be  separated  from  the  others.  Kossel  '  has  suggested  the  name 
paranuclein  for  these  nuclein  substances.  As  the  paranucleins 
amongst  themselves  are  very  different  and  have  only  an  apparent 
similarity  to  the  true  nucleins,  the  author "  has  proposed  the  name 
pseudonucleins  for  them. 

The  nuclein  of  spermatozoa,  which  does  not  yield  any  proteid 
on  splitting,  shows  a  great  similarity  to  the  substance  obtained  by 
Altmann  from  the  nucleins  of  Hoppe-Seyler's  first  group  by  the 
action  of  alkalies.  This  substance  was  called  nucleic  acid  by 
Altmanx  ^  and  Kossel,'  and  hence  this  nuclein  will  be  called 
nucleic  acid  in  the  future. 

The  nuclein  of  the  first  group  is,  according  to  Kossel,  true 
nuclein  or  simply  miclein.  Tbis  nuclein,  which  gives  phosphoric 
acid  as  well  as  proteid  and  xanthin  bases  on  splitting  with  acids,  is 
considered  by  Kossel  as  a  combination  between  proteid  and  nucleic 
acid. 

Pseudonucleins  or  Paranucleins.     These  bodies  are  obtained 

'  Du  Bois-Reymond's  Arcli.,  1891. 
«Zeitscbr.  f.  pliysiol.  CLem.,  Bd.  19. 
*Du  Bois-Reymond's  Arch.,  1889. 
*IMd.,  1891. 


^8  THE  ANIMAL   CELL. 

as  an  insoluble  residue  on  the  digestion  of  nncleoalbumins  or 
phosphoglycoproteids  with  pepsin  hydrochloric  acid.  Attention  is 
■called  to  the  fact  that  the  pseudonuclein  may  be  dissolved  by  the 
presence  of  too  much  acid  or  by  a  too  energetic  peptic  digestion. 
Pseudonucleins  contain  phosphorus,  which,  as  shown  by  Liebek- 
MANX,'  is  split  off  as  metaj)hosphoric  acid  by  mineral  acids.  The 
pseudonucleins  are  very  dissimilar.  One  group  of  these,  whose 
most  important  representative  is  the  long-known  pseudonuclein 
from  casein,  yields  ;pio  reducing  substance  on  boiling  with  mineral 
acids,  while  the  other  group,  to  which  the  pseudonuclein  from 
ichthulin  belongs,  does  yield  such  a  substance. 

The  pseudonucleins  are  amorphous  bodies  insoluble  in  water, 
alcohol,  and  ether,  but  readily  soluble  in  dilute  alkalies.  They  are 
not  soluble  in  very  dilute  acids,  and  may  be  precipitated  from  their 
solution  in  dilute  alkalies  by  adding  acid.  They  give  the  proteid 
reactions  very  strongly. 

In  preparing  a  pseudonuclein,  dissolve  the  mother-substance  in 
hydrochloric  acid  of  1-2  p.  m.,  filter  if  necessary,  and  add  pepsin 
solution,  and  allow  to  stand  at  the  bodily  temperature  for  about  24 
hours.  The  precipitate  is  filtered  off,  washed  with  water,  and 
purified  by  alternately  dissolving  in  very  faintly  alkaline  water  and 
reprecipitating  with  acid. 

Nucleins  or  True  Nucleins.  These  bodies  are  obtained  as  an 
insoluble  or  difficultly  soluble  residue  on  the  digestion  of  nucleo- 
proteids  with  j)epsin  hydrochloric  acid.  They  are  rich  in  phos- 
phorus, about  5^  and  above,  and  according  to  Liebermajstn^ 
metaphosphoric  may  also  be  split  off  from  the  true  nucleins  (yeast 
nuclein).  The  nucleins  are  decomposed  into  proteid  and  nucleic 
acid  by  caustic  alkali,  and  as  different  nucleic  acids  exist,  so  there 
also  exist  different  nucleins.  Certain  nucleins,  such  as  yeast 
nuclein  and  that  isolated  by  the  author '  from  the  pancreas  and 
mammary  gland,  give  a  reducing  carbohydrate  on  boiling  with 
dilute  acids,  while  other  nucleins,  like  that  from  the  thymus  gland, 
does  not.  All  nucleins  yield  xantliin  hases  or  nuclem  bases ^ 
so  called  by  Kossel,  on  boiling  with  dilute  acids.  The  nucleins 
contain  iron  to  a  considerable  extent.  They  act  like  rather  strong 
acids. 

'  Ber,  d.  deutsch.  chem.  Gesellsch..,  Bd.  21,  and  Centralbl.  f.  d.  med. 
Wissensch.,  Bd.  27. 

'^Pfliiger's  Arch.,  Bd.  47. 

^Zeitsclir.  f.  physiol   Chem.,  Bd,  19. 


NUCLEIC  ACIDS.  99 

The  nucleins  are  colorless,  aniorphons,  insoluble,  or  only  slightly 
soluble  in  water.  They  are  insoluble  in  alcohol  and  ether.  They 
are  more  or  less  readily  dissolved  by  dilute  alkalies.  Pepsin  hydro- 
chloric acid  or  dilute  mineral  acids  do  not  dissolve  them,  or  only  to 
a  slight  extent.  The  nucleius  give  the  biuret  test  and  Millox's 
reaction.  They  show  a  great  affinity  for  many  dyes,  especially  the 
basic  ones,  and  take  these  up  with  avidity  from  watery  or  alcoholic 
solutions.  On  burning  they  yield  an  acid  coke  containing  meta- 
phosphoric  acid  and  which  is  very  difficult  to  consume.  On  fusion 
with  saltpetre  and  soda  the  nucleins  yield  alkali  phosphates. 
According  to  Liebermann  '  the  nucleins  are  combinations  of  pro- 
teids  with  metaphosphoric  mixed  with  xanthin  bases. 

To  prepare  nucleins  from  cells  or  tissues,  first  remove  the  chief 
mass  of  proteids  by  artificial  digestion  with  pejDsin  hydrochloric 
acid,  lixiviate  the  residue  with  very  dilute  ammonia,  filter,  and 
precipitate  with  hydrochloric  acid.  The  precipitate  is  further 
digested  with  gastric  juice,  washed  and  purified  by  alternately  dis- 
solving in  very  faintly  alkaline  water,  and  reprecipitating  with  an 
acid,  washing  with  water,  and  treating  with  alcohol-ether.  A 
nuclein  may  be  prepared  more  simply  by  the  digestion  of  a  nucleo- 
proteid.  In  the  detection  of  nucleins  we  make  use  of  the  above- 
described  method  and  testing  for  phosphorus  in  the  product  after 
fusing  with  saltpetre  and  soda.  Naturally  the  phosphates,  lecithins 
(and  jecorin)  must  first  be  removed  by  treatment  with  acid,  alcohol, 
and  ether,  respectively.  We  must  specially  call  attention  to  the 
fact,  as  shown  by  Liebermann,''  of  the  very  great  difficulty  in 
removing  lecithin  by  means  of  alcohol-ether,  No  exact  methods 
are  known  for  the  quantitative  estimation  of  nucleins  in  organs  or 
tissues. 

Nucleic  Acids.  Kossel  differentiates  between  the  various 
nucleic  acids  by  the  decomposition  products.  All  yield  nuclein 
bases  as  clea,vage  products,  but  the  nucleic  acid  from  bull  sperma- 
tozoa yields  chiefly  xanthin,  while  that  from  the  calf's  thymus  yields 
only  adenin.  According  to  Kossel  '  it  is  probable  that  there  exist 
four  nucleic  acids,  one  for  each  nuclein  base,  namely,  an  adenylic,  ?o 
guanylic  acid,  etc.  The  nucleic  acids  thus  far  investigated,  with 
the  exception  of  adenylic  acid  from  the  calf's  thymus,  were  only 
mixtures  of  several  nucleic  acids.  Another  circumstance  which 
makes  the  acceptance  of  many  nucleic  acids  necessary  is  that  certain 

'  Centralbl.  f.  d.  med.  Wissensch. ,  Bd.  27. 

^Pfluger's  Arch.,  Bd.  54. 

»Ber.  d.  deutsch.  cliem.  Gesellsch.,  Bd.  26.  S.  2753. 


100  THE  ANIMAL   CELL. 

of  the  nucleic  acids,  such  as  those  from  yeast,  pancreas,  and  the 
mammary  glands,  give  reducing  carbohydrates  or  carbohydrate 
groups,  while  the  others,  such  as  the  nucleic  acid  from  the  calf's 
thymus,  salmon,  and  carp  sperm,  do  not.  In  the  far-reaching 
splitting  of  adenylic  acid  with  sulphuric  acid  Kossel  and  JSTeu- 
MANif '  obtained  levulinic  acid, 

A  general  formula  for  the  nucleic  acids  cannot  be  given,  and  the 
composition  of  the  different  nucleic  acids  analyzed  is  naturally  very 
different.  The  nucleic  acids  do  not  contain  any  sulphur,  but  do 
contain  nitrogen  and  phosphorus  in  the  relation  of  3  :  1,  according 
to  Kossel.''  The  quantity  of  phosphorus  is  large.  In  the  nucleic 
acid,  with  the  formula  C^^H^NgFjO^^,  obtained  by  Mieschek' 
from  salmon  sperm,  the  quantity  of  phosphorus  was  over  9^. 

Kossel*  assumes  that  the  nucleic  acid  contains  a  nucleus  which  consists  of 
phosphorus  atoms  combined  similar  to  polymetaphosphoric  acids.  According- 
to  LiEBERMANN  ^  the  nucleic  acids  contain  metaphosphoric  acid,  probably  the 
mono-acid,  and  he  has  also,  as  above  stated,  split  off  metaphosphoric  acid  from 
nuclein.  Other  acids  rich  in  phosphorus  are  formed  by  the  action  of  alkali  or 
boiling  water  on  nucleic  acids.  From  adenylic  acid  and  later  from  other  nucleic 
acids  Kossel  and  Neumann'  have  prepared  an  acid  called  by  them  tJiyminic 
acid,  which  on  boiling  with  sulphuric  acid  yields  a  crystalline  substance, 
tJiymin,  having  the  formula  CsHeNaOa.''  From  the  thymin  they  obtained 
a  new  cleavage  product,  a  base  called  cytosin,  with  the  probable  formula 
CaiH3oN,604  +  SH^O. 

The  nucleic  acids  are  amorphous,  white,  and  of  a  strongly  acid 
reaction.  They  are  readily  soluble  in  ammoniacal  or  alkaline 
water.  They  are  not  precipitated  from  these  solutions  by  an  excess 
of  acetic  acid,  but  are  precipitated  by  a  slight  excess  of  hydrochloric 
acid,  especially  in  the  presence  of  alcohol.  They  are  insoluble  in 
alcohol  and  ether.  The  nucleic  acids  give  precipitates  with  pro- 
teids  which  have  been  considered  as  nucleins.  The  question 
whether  these  precipitates  are  real  nucleins  has  not  been  settled. 

Nucleic  acid  may  be  best  prepared,  according  to  Altmajstn,^ 
from  yeast.     Each  1000  c.c.  of  yeast  is  treated  with  3250  c.c.  dilute 

1  Sitzungsber.  d.  Berl.  Akad.  d.  Wissensch. ,  Bd.  18,  1894. 

^Du  Bois-Reymond's  Arch.,  1892. 

3L.  c. 

4L.  c;  see  also  Centralbl.  f.  d.  med.  Wissensch.,  1893,  S.  497. 

spfliiger's  Arch.,  Bd.  47,  and  Centralbl.  f.  d.  med.  Wissensch.,  1893,  S.  465 
and  737. 

*Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  26,  and  Sitzungsber.  der  Berl.  Akad,, 
1.  c. 

'Du  Bois-Reymond's  Arch.,  1894,  Physiol,  Abth. 

^IMd.,  1889,  Physiol.  Abth.,  S.  524. 


NUCLEOHISTON.  101 

caustic  soda  of  about  3^  for  five  minutes  at  the  temperature  of  the 
room.  Tlie  chief  portion  of  the  sodium  hydrate  is  tlien  neutralized 
with  hydrochloric  acid,  and  then  acetic  acid  added  in  excess.  The 
liquid  separated  from  the  precipitated  proteids  is  acidified  with 
hydrochloric  acid  until  it  contains  3-5  p.  m.  HCl,  and  then  mixed 
with  an  equal  volume  of  alcohol  of  the  same  acidity.  Imj^are 
nucleic  acid  separates  out  and  may  be  purified  by  dissolving  in 
ammoniacal  water  and  repeatedly  treating,  as  above,  Avith  acetic 
acid,  hydrochloric  acid,  and  alcohol. 

Plastin. — On  the  solution  of  the  nucleins  from  cell  nuclei  of  certain  plants 
in  dilute  soda  solution  a  residue  is  obtained  which  is  characterized  by  its  great 
insolubility.  This  substance,  of  which  the  spongioplasm  of  the  body  of  the 
cell  and  the  nucleus  granixles  are  alleged  to  be  composed,  is  considered  as  a 
nuclein  modification  of  great  insolubility,  although  its  nature  is  not  known. 

Nucleoproteids  with  relatively  high  percentage  of  phosphorus 
and  of  a  markedly  acid  character  occur  in  cell  nuclei.  Like  the 
nucleins  they  are  also  combinations  of  proteid  with  nucleic  acid. 
They  are,  however,  richer  in  proteid  than  the  nucleins,  and  differ 
from  them  in  that  their  neutral  solutions  decompose  with  the 
splitting  off  of  coagulated  proteid  on  boiling,  and  also  in  that  they 
yield  nucleins  on  their  peptic  digestion.  Among  the  nucleoproteids 
the  most  carefully  studied  is  niicleohiston. 

Nucleohiston  is  the  name  given  by  Kossel  and  Lilienfeld  '  to 
the  nucleoproteid  isolated  by  them  from  the  calf's  thymus.  Its 
composition  is:  C  48.46;  H  7.00;  N  16.86;  P.  3.025;  S  0.701; 
0  23.95^.  On  heating  its  solution  it  splits  into  coagulated  proteid. 
On  peptic  digestion  it  yields  nuclein.  On  treating  with  hydro- 
chloric acid  of  0.8^  it  splits  into  nuclein  and  a  proteid  substance 
soluble  in  hydrochloric  acid,  and  which  differs  from  other  proteids 
in  being  insoluble  in  an  excess  of  ammonia.  Kossel  has  called 
this  substance  histoti. 

Nucleohiston  is  precipitated  from  a  neutral  solution  by  means 
of  acetic  acid,  and  is  not  redissolved  by  an  excess  of  acetic  acid. 
The  neutral  solution  is  precipitated  by  alcohol,  but  not  on  saturating 
with  MgSO^.  Nucleohiston  is  easily  dissolved  in  dilute  alkalies  or 
alkali  carbonates.  It  is  soluble  in  glacial  jicetic  acid,  hydrochloric 
and  sulplmric  acids.  The  relationship  of  the  nucleins  and  histon 
to  the  coagulation  of  the  blood  will  be  spoken  of  in  Chapter  VI. 

Nucleohiston  is  prepared  by  precipitating  the  filtered  watery 
extract  of  the  gland,  free  from  cellular  elements,  with  acetic  acid, 
and  purifying  by  repeated  solution  in  water  slightly  alkaline  with. 

'  Zeitschr.  f.  physiol.  Chem.,  Bd.  18. 


102  TEE  ANIMAL    CELL. 

soda  and  precipitating  with  acetic  acid.  Finally  it  is  washed  with 
water  containing  acetic  acid  and  then  with  alcohol,  then  extracted 
with  cold  and  hot  absolute  alcohol  and  lastly  with  ether. 

The  compound  proteids '  described  by  other  investigators  under  the  names 
tissue  fibrinogen  and  cell  fibrinogen  are  to  be  considered  as  impure  nucleohiston 
or  bodies  very  closely  related  thereto.  The  cytoglobin  and  preglobulin  described 
by  Alex.  Schmidt  *  as  important  cell  constituents  also  belong  to  the  same 
group  as  the  nucleohiston.  Cytoglobin  is  to  be  considered  as  the  alkali  combi- 
nation of  preglobulin.  The  residue  remaining  on  the  complete  exhaustion  of 
the  cells  with  alcohol,  water,  and  common-salt  solution  is  called  c?/^m  by  Alex. 
Schmidt.  The  relationship  of  these  bodies  to  the  coagulation  of  blood  will  be 
spoken  of  in  Chapter  VI. 

Among  the  decomposition  products  of  nuclein  substances  the 
xanthin  bases  are  of  especially  great  interest. 

Xanthin  Bases.  With  this  name  we  designate  a  group  of  bodies 
consisting  of  carbon,  hydrogen,  nitrogen,  and  in  most  cases  also  of 
oxygen,  which,  by  their  composition,  show  a  relationship  not  only 
among  themselves,  but  also  with  uric  acid.  These  bodies  are 
xanthin,  hypoxanthin,  episarkin,  guanin,  adenin,  heteroxanthin, 
jparaxanthin,  and  carnin.  The  bodies  theobromin  and  theo- 
PHTLLiisr  (both  dimethylxanthin)  and  caffein  (trimethylxanthin) 
occurring  in  the  vegetable  kingdom  also  belong  to  this  groap. 

The  composition  of  these  bodies  occurring  in  the  animal  body  is  as  follows  : 

Uric  acid C5H4N4O3 

Xanthin C5H4N4O2 

Heteroxanthin  (methylxanthin) C6H6N4O3 

Paraxanthin  (dimethylxanthin) C7H8N4O2 

Guanin CsHsNsO 

Hypoxanthin C5H4N4O 

Adenin C5H5N5 

Episarkin , C4H6N3O  (?) 

Carnin C7H8N4O3 

After  SALOMOisr  ^  had  shown  the  occurrence  of  xanthin  bases 
in  young  cells  the  importance  of  the  xanthin  bases  as  decomposition 
products  of  cell  nuclei  and  of  nucleins  was  shown  by  the  pioneering 
researches  of  Kossel,  who  discovered  adenin  and  theophyllin.  In 
those  tissues  in  which,  as  in  the  glands,  the  cells  have  kept  their 
original  state  the  xanthin  bases  are  not  found  free,  but  in  combi- 
nation with  other  atomic  groups  (nucleins).  In  such  tissue,  on  the 
contrary,  as  in  muscles,  which  are  poor  in  cell  nuclei,  the  xanthin 
bases  are  found  in  the  free  state.  As  the  xanthin  bases,  as  sug- 
gested by  Kossel,  stand  in  close  relationship  to  the  cell  nucleus,  it 

1  See  p.  91. 

2  Zur  Blutlehre. 

'  Sitzungsber.  d.  Bot.  Vereins  der  Provinz  Brandenburg,  1880. 


XAyiHlX   BASES  10.^ 

is  easy  to  understand  why  the  quantity  of  these  bodies  is  so  greatly 
increased  when  large  quantities  of  nucleated  cells  appear  in  such 
places  as  were  before  relatively  poorly  endowed.  As  an  example  of 
this  we  have  in  leucaemia  blood  extremely  rich  in  leucocytes.  In 
such  blood  Kossel'  found  1.04  p.  m.  xanthin  bases,  against  only 
traces  in  the  normal  blood.  That  the  xanthin  bases  are  also  inter- 
mediate steps  in  the  formation  of  urea  or  uric  acid  in  the  animal 
organism,  is  probable,  and  will  be  shown  later  (see  Chapter  XV). 

Only  a  few  of  the  xanthin  bases  have  been  found  in  the  urine 
or  in  the  muscles.  Only  four  xanthin  bases — xanthin,  guanin, 
hypoxanthin,  and  adenin, — have  been  obtained,  thus  far,  as  cleav- 
age products  of  nucleins.  In  regard  to  the  other  xanthin  bases  we 
refer  the  reader  to  their  respective  chapters.  Only  the  above  four 
bodies,  the  real  nuclein  bases,  will  be  treated  of  at  this  time. 

Of  these  four  bodies  the  xanthin  and  guanin  form  one  special 
group,  and  hypoxanthin  and  adenin  another.  By  the  action  of 
nitrous  acid  guanin  is  couverted  into  xanthin  and  adenin  into 
hypoxanthin. 

C,H,N,O.NH  +  HNO,  =  C,H,N,0,  +  N,  +  H,0; 

Guanin.  Xanthin. 

C,H,N,.NH  +  HNO,  =  C,H,N,0  +  N,  +  H,0. 

Adenin.  Hypoxanthin. 

By  putrefaction  guanin  is  converted  into  xafathin  and  adenin 
into  hypoxanthin.  On  cleavage  with  hydrochloric  acid  all  four  of 
the  bodies  are  converted  into  ammonia,  glycocoll,  carbon  dioxide, 
and  formic  acid.  Uric  acid  yields,  under  the  same  conditions, 
ammonia  and  carbon  dioxide,  and  also  glycocoll.  On  oxidation  with 
hydrochloric  acid  and  potassium  chlorate  xanthin,  bromadenin,  and 
bromhypoxanthin  yield  alloxan  and  urea;  guanin  yields  guanidin, 
parabanic  acid  (an  oxidation  product  of  alloxan),  and  carbon 
dioxide.  Uric  acid  in  acid  solution  is  oxidized  into  urea,  alloxan 
and  then  further  into  parabanic  acid.  The  close  relationship 
of  these  bases  to  each  other  and  to  uric  acid  is  apparent. 
Xanthin  has  been  prepared  synthetically  by  Oautier  '  by  heating 
hydrocyanic  acid  with  water  and  acetic  acid. 

The  nuclein  bases  form  crystalline  salts  with  mineral  acids, 
which  are  decomposed  by  water  with  the  exception  of  the  adenin 

>  Zeitschr.  f.  physiol.  Chem..  Bd.  7,  S.  23. 
'Compt.  rend.,  Tome  98,  p.  1523. 


104  THE  ANIMAL    CELL. 

salts.  They  are  easily  dissolved  by  alkalies,  while  with  ammonia 
their  action  is  somewhat  different.  They  are  all  precipitated  from 
acid  solution  by  phosphotungstic  acid,  also  they  separate  as  a  silver 
combination  on  the  addition  of  ammonia  and  ammoniacal  silver- 
nitrate  solution.  These  precipitates  are  soluble  in  boiling  nitric 
acid  of  1.1  sp.  gr.  All  xanthin  bases  with  the  exception  of  cailein 
and  theobromin  are  precipitated  by  Fbhlijstg's  solution  (see  Chap. 
XV)  in  the  presence  of  a  reducing  substance  such  as  hydroxylamin 
(Drechsel  and  Balke').  Copper  sulphate  and  sodium  bisulphite 
may  also  be  used  to  advantage  in  their  precipitation  (Keugee^). 
This  behavior  of  the  xanthin  bases  is  made  use  of  in  their  precipita- 
tion and  preparation. 

Xanthin,  C^H^N^O,  =  ^     "        ^    *        >C0  (E.  Fischer'),  is 

found  in  the  muscles,  liver,  spleen,  pancreas,  kidneys,  testicles, 
carp-sperm,  thymus,  and  brain.  It  occurs  in  small  quantities  as  a 
physiological  constituent  of  urine,  and  it  has  been  found  rarely  as  a 
urinary  sediment  or  calculus.  It  was  first  observed  in  such  a  stone 
by  Marcet,  Xanthin  is  found  in  larger  amounts  in  a  few  varieties 
of  guano  (Jarvis  guano). 

Xanthin  is  amorphous,  or  forms  granular  masses  of  crystals. 
It  is  very  slightly  soluble  in  water,  in  14,151-14,600  parts  at 
+  16°  C,  and  in  1300-1500  parts  at  100°  C.  (Almeit').  It  is  in- 
soluble in  alcohol  or  ether,  but  is  dissolved  by  alkalies  or  acids. 
With  hydrochloric  acid  it  gives  a  crystalline,  difficultly  soluble  com- 
bination. With  very  little  caustic  soda  it  gives  a  readily  crystal- 
jizable  combination,  which  is  easily  dissolved  by  an  excess  of  alkali. 
Xanthin  dissolved  in  ammonia  gives  with  silver  nitrate  an  insolu- 
ble, gelatinous  precipitate  of  xanthin  silver.  This  precipitate  is 
dissolved  by  nitric  acid,  and  by  this  means  an  easily  soluble  crystal- 
line double  combination  is  formed.  A  watery  xanthin  solution  is 
precipitated  on  boiling  with  copper  acetate.  At  ordinary  tempera- 
tures xanthin  is  precipitated  by  mercuric  chloride  and  by  ammoni- 
acal basic  lead  acetate.  It  is  not  precipitated  with  basic  lead 
acetate  alone. 

When  evaporated  to  uryness  in  a  porcelain  dish  with  nitric  acid 

>Zur  Kenntniss  der  Xanthinkorper.     Inaug.  Diss.     Leipzig,  1893. 
*Zeitschr.  f.  physiol.  Chem.,  Bd.  18. 

•Annal.  d.  Chem.,  Bd.  215.  •         '       -  . 

'•Journ.  f.  prakt.  Chem.,  Bd.  96. 


GUANIN.  105 

xauthin  gives  a  yellow  residue,  which  turns,  on  the  addition  of 

caustic  soda,  first  red,  and,  after  heating,  purple-red.     If  we  add 

some  chloride  of  lime  to  some  caustic  soda  in  a  porcelain  dish  and 

add  the  xanthin  to  this  mixture,  at  first  a  dark  green  and  then 

quickly  a  brownish  halo  forms  around  the  xanthin  grains  and  then 

disappears   (Hoppe-Seylee).     If  xanthin  be   warmed  in  a  small 

vessel  on  the  water-bath  with  chlorine-water  and  a  trace  of  nitric 

acid  and  evaporated  to  dryness,  when  the  residue  is  exposed  under 

a  bell- jar  to  the  vapors  of  ammonia  a  red  or  purple- violet  color  is 

produced  (Weidel's  reaction). 

•       riTTA^r^  NH.CH:C.NH     ^„  ^       .        . 

Guanin,  C^H^Is^O  =  ts^tjj  .  q  j^j|  q  .  ^>^^-  Guanm      is 

found  in  organs  rich  in  cells,  such  as  the  liver,  spleen,  pancreas, 
testicles,  and  in  salmon-sperm.  It  is  further  found  in  the  muscles 
(in  very  small  amounts),  in  the  scales  and  in  the  air-bladder  of 
certain  fishes  as  iridescent  crystals  of  guanin  lime;  in  the  retina 
epithelium  of  fishes,  in  guano,  and  in  the  excrement  of  spiders  it  is 
found  as  chief  constituent.  It  also  occurs  in  human  and  pig  urine. 
Under  pathological  conditions  it  has  been  found  in  leucaemic  blood, 
and  in  the  muscles,  ligaments,  and  articulations  of  pigs  with  guanin 
gout.  * 

Guanin  is  a  colorless,  ordinarily  amorphous  powder  which  may 
be  obtained  as  small  crystals  by  allowing  its  solution  in  concentrated 
ammonia  to  spontaneously  evaporate.  It  is  nearly  insoluble  in 
water,  alcohol,  and  ether.  It  is  easily  dissolved  by  mineral  acids 
and  alkalies,  but  it  dissolves  with  great  difficulty  in  ammonia.  Ac- 
cording to  WuLFF  '  100  c.c.  of  cold  ammonia  solution  containing 
1,  3,  and  5^  NH,  dissolve  9,  15,  and  19  milligrammes  guanin  re- 
spectively. The  solubility  is  relatively  increased  in  hot  ammonia 
solution.  The  hydrochloric-acid  salt  readily  crystallizes,  and  this 
has  been  recommended  by  Kossel  ''  in  the  microscopical  detection 
of  guanin  on  account  of  its  behavior  to  polarized  light.  Very 
dilute  guanin  solutions  are  precipitated  by  both  picric  acid  and 
metaphosphoric  acid.  These  precipitates  may  be  used  in  the  quan- 
titative estimation  of  guanin.  The  silver  combination  dissolves  with 
difficulty  in  boiling  nitric  acid,  and  on  cooling  the  double  combina- 
tion  crystallizes   out   readily.     Guanin  acts  like   xanthin  in  the 

'Zeitschr.  f.  pbysiol.  Chem.,  Bd.  17,  S.  505. 

'  Ueber  die   chem.   Zusammensetzung  der  Zelle.     Verhandl.   der  physiol. 
Gesellsch.  zu  Berlin.  1890-1891.  Nos.  5  and  6. 


106  THE  ANIMAL   CELL. 

nitric-acid  test,  but  gives  with  alkalies  on  heating  a  more  bluish- 
yiolet  color,  A  warm  solution  of  gaanin  hydrochloride  gives  with 
a  cold  saturated  solution  of  picric  acid  a  yellow  precipitate  consist- 
ing of  silky  needles  (Capeanica  ').  With  a  concentrated  solution 
of  potassium  bichromate  a  guanin  solution  gives  a  crystalline, 
orange-red  precipitate,  and  with  a  concentrated  solution  of  potas- 
sium ferricyanide  a  yellowish-brown,  crystalline  precipitate  (Ca- 
PEANICA)  . 

The  composition  of  these  and  other  gnanin  combinations  have 

been  studied  by  Kossel  and  Wulff.'' 

...  ~  ^  -r^-.  _.  _^  ^      NH.CH  :  C.NH      ^^ 

Hypoxanthm  or  Saekin,  C^H^N.O  =  ^^„  ^       ^  >  00  or 

"  '  ,  ■  /  ^^  >00  (Keugee').  This  body  is  found  in  the  same 
OH.NH.O  :  N  ^  '  "^ 

tissues  as  xanthin.  It  is  especially  abundant  in  the  sperm  of  the 
salmon  and  carp.  Hypoxanthin  occurs  also  in  the  marrow  and  in 
very  small  quantities  in  normal  urine,  and,  as  it  seems,  also  in  milk. 
It  is  found  in  rather  considerable  quantities  in  the  blood  and  urine 
in  leucaemia. 

Hypoxanthin  forms  very  small  colorless  crystalline  needles.  It 
dissolves  in  300  parts  cold  and  78  parts  boiling  water.  It  is  nearly 
insoluble  in  alcohol,  but  is  dissolved  by  acids  and  alkalies.  The 
combination  with  hydrochloric  acid  is  crystalline,  but  is  more  soluble 
than  the  corresponding  xanthin  combination.  This  combination  is 
easily  soluble  in  dilute  alkalies  and  ammonia.  The  silver  combina- 
tion dissolves  with  difficulty  in  boiling  nitric  acid.  On  cooling  a 
mixture  of  two  hypoxanthin  silver,  nitrate  combinations  not  having 
a  constant  composition  separates  out.  On  treating  this  mixture 
with  ammonia  and  excess  of  silver  nitrate  in  the  warmth,  a  hypo- 
xanthin silver  combination  is  formed,  which  when  dried  at  120°  0. 
has  a  constant  composition,  2(C^HjAg5]Sr^O)H20,  and  which  is  used 
in  the  quantitative  estimation  of  hypoxanthin.  Hypoxanthin 
picrate  is  soluble  with  difficulty,  but  if  a  boiling-hot  solution  of  the 
same  is  treated  with  a  neutral  or  only  faintly  acid  solution  of  silver 
nitrate  the  hypoxanthin  is  nearly  quantitatively  precipitated  as  the 
compound  C,H3AgN,O.C,H^(NOj30H.  Hypoxanthin  does  not 
form  any  combination  with  metaphosphoric  acid.     When  treated, 

>  Zeitschr.  f .  physiol.  Chem. ,  Bd.  4,  S.  233. 
^Ibid.,  Bd.  17,  S.  468. 
3  7^>^•d,  Bd.  18,  S.  459. 


ADENIN,  lOT 

like  xanthin,  with  nitric  acid,  it  yields  a  nearly  colorless  residue 
which  on  warming  with  alkali  does  not  turn  red.  Hjrpoxanthin 
does  not  give  "Wei del 's  reaction.  After  the  action  of  hydrochloric 
acid  and  zinc  a  hypoxanthin  solution  becomes  first  ruby-red  and 
then  brownish  red  in  color  on  the  addition  of  an  excess  of  alkali 
(KOSSEL  '). 

A  J     •     J  /-(  TT  XT        NH.CH  :  C.NH     _,  /TkT-i-r\ 
Adenin/  C,H,N.  =     CH  :  K.C  :  N  ^      ^^^  ^^ 

"  *         ■   ■'   -»j-  >C  (NH),  KruCtEr/  was  first  found  by  Kossel  in 

the  pancreas.  It  occurs  in  all  nucleated  cells,  but  in  greatest 
(quantities  in  the  sperm  of  the  carp  and  in  the  thymus.  Adenin 
has  also  been  found  in  leucajmic  nriae  (Stadthagex  ^).  It  may 
be  obtained  in  large  quantities  from  tea-leaves.  Adenin  crystallizes 
with  3  mol.  water  of  crystallization  in  long  needles  which  become 
opaque  gradually  in  the  air,  but  much  more  rapidly  when  warmed. 
If  the  crystals  are  warmed  slowly  with  a  quantity  of  water  insuffi- 
cient for  solution,  they  become  suddenly  cloudy  at  53°  C,  a  charac- 
teristic reaction  for  adenin.  It  dissolves  in  1080  parts  cold  water, 
but  is  easily  soluble  in  warm.  It  is  insoluble  in  ether,  but  some- 
what soluble  in  hot  alcohol.  Adenin  is  easily  soluble  in  acids  and 
alkalies.  It  is  more  easily  soluble  in  ammonia  solution  than  gnanin, 
but  less  soluble  than  hypoxanthin.  The  silver  combination  of 
adenin  is  difficultly  soluble  in  warm  nitric  acid,  and  deposits  on  cool- 
ing as  a  crystalline  mixture  of  adenin  silver  nitrates.  With  picric 
acid  adenin  forms  a  compound,  C5H^X^.CjH^(]S"Oj30H,  which  is 
very  insoluble  and  whicli  separates  more  readily  than  the  hypoxan- 
thin picrate  and  which  can  be  iised  in  the  quantitative  estimation 
of  adenin.  We  also  have  an  adenin  mercury  j)icrate.  Adenin  gives 
a  precipitate  with  metaphosphoric  acid,  if  the  solution  is  not  too 
dilate,  which  dissolves  in  an  excess  of  the  acid.  Adenin  hydro- 
chloride gives  with  gold  chloride  a  double  combination  which  con- 
sists in  part  of  leaf -shaped  aggregations  and  in  part  of  cubical  or 
prismatic  crystals,  often  with  rounded  corners.  This  compound  is 
used  in  the  microscopic  detection  of  adeniu.  With  the  nitric-acid 
test  and  with  Weidel's  reaction  adenin  acts  in  the  same  way  as 

'Zeitschr.  f.  physiol.  Chem.,  Bd.  12. 
'See  Kossel,  ihid.,  Bdd.  10  and  12. 
» Ibid. ,  Bd.  18.  S.  459. 
■•Vircliow's  Arch.,  Bd.  109. 


108  THE  ANIMAL    CELL. 

hypoxanthin.     The  same  is  true  for  its  behavior  to  hydrochloric 
acid  and  zinc  and  subsequent  addition  of  alkali. 

The  principle  for  the  preparation,  detection,  and  the  quantita- 
tive estimation  of  the  four  above-described  xanthin  bodies  in  organs 
and  tissues  is,  according  to  Kossel  and  his  pupils,  as  follows:  The 
finely  divided  organ  or  tissue  is  boiled  for  three  or  four  hours  with 
sulphuric  acid  of  about  5  p.  m.  The  filtered  liquid  is  freed  from 
proteid  by  basic  lead  acetate,  and  the  new  filtrate  is  treated  with 
sulphuretted  hydrogen  to  remove  the  lead,  again  filtered,  concen- 
trated, and,  after  adding  an  excess  of  ammonia,  precipitated  with 
ammoniacal  silver  nitrate.  The  silver  combination  (with  the  addi- 
tion of  some  urea  to  prevent  nitrification)  is  dissolved  in  not  too 
large  a  quantity  of  boiling  nitric  acid  of  sp.  gr.  1.1,  and  this  solu- 
tion filtered  boiling  hot.  On  cooling  the  xanthin  silver  remains  iti 
the  solution,  while  the  double  combination  of  gnanin,  hypoxanthin, 
and  adenin  crystallizes  out.  The  xanthin  silver  may  be  precipi- 
tated from  the  filtrate  by  the  addition  of  ammonia,  and  the  xanthin 
set  free  by  means  of  sulphuretted  hydrogen.  The  three  above- 
mentioned  silver  nitrate  combinations  are  decomposed  in  water  with 
ammonium  sulphide  and  heat;  the  silver  sulphide  is  filtered,  the 
filtrate  concentrated,  saturated  with  ammonia,  and  digested  on  the 
water-bath.  The  guanin  remains  undissolved,  while  the  other  two 
bases  pass  into  solution.  A  part  of  the  guanin  is  still  retained  by 
the  silver  sulphide,  and  may  be  liberated  by  boiling  it  with  dilute 
hydrochloric  acid  and  then  saturating  the  filtrate  with  ammonia. 
When  the  above  filtrate,  containing  the  adenin  and  hypoxanthin, 
which  has  been,  if  necessary,  freed  from  ammonia  by  evaporation, 
is  allowed  to  cool,  the  adenin  separates,  while  the  hypoxanthin 
remains  in  solution.  According  to  Balke  '  we  can  to  advantage 
precipitate  the  xanthin  bases  with  copper  sulphate  and  hydroxyla- 
min  as  above  mentioned  and  then  further  separate  the  bodies. 

The  prominent  points  in  the  above  method  are  made  use  of  in 
the  quantitative  estimation  of  xanthin  bases.  The  xanthin  is 
weighed  as  xanthin  silver.  The  three  silver  nitrate  combinations 
are  transformed  into  the  corresponding  silver  combination  by  the 
addition  of  ammonia  with  silver  nitrate  and  then  this  acted  on,  after 
thorough  washing,  by  ammonium  sulphide.  Gruanin  is  weighed 
as  such.  The  ammoniacal  filtrate  containing  the  adenin  and 
hypoxanthin,  and  which  must  not  be  mixed  with  the  hydrochloric- 
acid  extract  of  the  silver  sulphide,  is  neutralized  and  treated  with 
a  cold  concentrated  solution  of  sodium  picrate  until  the  solution  is 
pronouncedly  yellow.  The  adenin  picrate  is  filtered  off  imme- 
diately, washed  on  the  filter  with  water,  dried  at  above  100°  C, 
and  weighed.  The  filtrate  containing  the  hypoxanthin  is  gradually 
treated,  while  boiling  hot,  with  silver  nitrate,  and  when  cold  treated 
with  silver  nitrate  to  see  whether  precipitation  has  been  complete. 

'  Zur  Kenntnisse  der  Xanthinkorper.     Inaug.  Diss.     Leipzig,  1893. 


MINERAL   CONSTITUENTS   OF  THE  CELL  10!> 

The  hvpoxantbin  picrate  is  washed,  dried  at  100°  C,  and  weighed. 
In  regard  to  the  composition  of  these  compounds  see  pages  lOG  and 
107.  This  method  of  separating  adeniu  and  hyj^oxanthin  presup- 
poses that  the  liquid  does  not  contain  any  hydrocliloric  acid. 

The  above  method  of  separation  with  ammonia  does  not  give 
exact  results  on  account  of  the  not  inconsiderable  solubility  of 
guanin  in  warm  ammonia.  According  to  Kossel  and  Wulff  '  the 
guanin  may  therefore  be  precipitated  from  sufficiently  dilute  solu- 
tions by  an  excess  of  metaphosphoric  acid  and  tiie  nitrogen  deter- 
mined in  the  washed  precipitate  by  Kjeldahl's  method.  The 
adenin  and  hypoxanthin  may  be  precij^itated  from  the  filtrate  by 
ammoniacal  silver  nitrate.  The  silver  compound  is  decomposed 
with  very  dilute  hydrochloric  acid  and  the  adenin  separated  from 
the  hypoxanthin  according  to  the  suggestion  of  Bruhns.' 

Mineral  bodies  are  never-failing  constituents  of  the  cell.  These 
mineral  bodies  are  potassium,  sodium,  calcium,  magnesium,  iron, 
phosphoric  acid,  and  chlorine.  In  regard  to  the  alkalies  we  find  in 
general  in  the  animal  organism  that  the  sodium  combinations  are 
more  abundant  in  the  fluids,  and  the  potassium  combinations  in  the 
form-constituents  and  in  the  protoplasm.  Corresponding  to  this 
the  cell  contains  potassium,  chiefly  as  jDhosphate,  while  the  sodium 
and  chlorine  combinations  occur  less  abundantly.  According  to 
the  ordinary  views  the  potassium  combinations,  especially  the 
potassium  phosphate,  are  of  the  greatest  importance  for  the  life  and 
development  of  the  cell,  even  though  we  do  not  know  the  nature  of 
the  importance. 

In  regard  to  the  phosphoric  acid  there  seems  to  be  no  doubt 
thiit  its  importance  lies  chiefly  in  that  it  takes  part  in  the  forma- 
tion of  nucleins  and  thereby  indirectly  makes  possible  the  processes 
of  growth  and  division,  which  are  dependent  upon  the  cell  nucleus. 
LoEW »  has  shown,  by  means  of  cultivation  experiments  on  algae 
Spirogyra,  that  only  on  the  supplying  of  phosphates  (in  his  experi- 
ments potassium  phosphate)  was  the  nutrition  of  the  cell  nucleus 
made  possible,  and  thereby  the  growth  and  division  of  the  cells. 
The  cells  of  the  Spirogyra  can  be  kept  alive  and  indeed  produce 
starch  and  proteids  for  some  time  without  a  supply  of  phosphates, 
but  its  growth  and  propagation  suffers.  Phosphoric  acid  is  also 
without  doubt  of  importance  in  the  formation  of  the  lecithins. 

Iron   seems  to    occur   especially  in  the   nucleus,    because    the 

'Zeitscbr.  f.  physiol.  Chem.,  Bd.  17. 

»7Md.,  Bd.  14,  S.  559. 

» Biologisches  Centralblatt,  Bd.  11,  1891,  S.  269. 


110  THE  ANIMAL   CELL. 

nucleins  are  very  ricli  therein.  The  regular  occurrence  of  earthy 
phosj^hates  in  all  cells  and  tissues,  as  also  the  diflBculty  or  rather  the 
impossibility  of  separating  these  bodies  from  the  protein  bodies 
without  modifying  them,  leads  to  the  supposition  that  these  mineral 
bodies  are  of  unknown  but  nevertheless  great  importance  for  the 
life  of  the  ceil,  as  well  as  the  chemical  processes  going  on  within 
them. 


CHAPTER   VI. 

THE   BLOOD. 

The  blood  is  to  be  considered  from  a  certain  standpoint  as  a 
fluid  tissue,  and  it  consists  of  a  transparent  liquid,  the  blood-2)lasma, 
in  which  a  vast  number  of  solid  particles,  the  red  and  luhite  blood- 
corpusdes  (and  the  blood-plates)  are  suspended. 

Outside  of  the  organism  the  blood,  as  is  well  known,  coagulates 
more  or  less  quickly ;  but  this  coagulation  is  accomplished  generally 
in  a  few  minutes  after  leaving  the  body.  All  varieties  of  blood  do 
not  coagulate  with  the  same  degree  of  rapidity.  Some  coagulate 
more  quickly,  others  more  slowly.  Among  the  varieties  of  blood 
thus  far  investigated  the  blood  of  the  horse  coagulates  most  slowly. 
The  coagulation  may  be  more  or  less  retarded  by  quickly  cooling; 
and  if  we  allow  equine  blood  to  flow  directly  from  the  vein  into  a 
glass  cylinder  which  is  not  too  wide  and  which  has  been  cooled,  and 
let  it  stand  at  0°  C,  the  blood  may  be  kept  fluid  for  several  days. 
An  upper,  amber-yellow  layer  of  plasma  gradually  separates  from  a 
lower,  red  layer  composed  of  blood-corpuscles  with  only  a  little 
plasma.  Between  these  we  observe  a  whitish-gray  layer,  which 
consists  of  white  blood-corpuscles. 

The  plasma  thus  obtained  and  filtered  is  a  clear  amber-yellow 
alkaline  liquid  which  remains  fluid  for  some  time  when  kept  at 
0°  C,  but  soon  coagulates  at  the  ordinary  temperature. 

The  coagulation  of  the  blood  may  be  prevented  in  other  ways. 
After  the  injection  of  peptone  or,  more  correctly,  albumose  solu- 
tions into  the  blood  (in  the  living  dog),  the  blood  does  not  coagulate 
on  leaving  the  veins  (Fai^o,'  Schmidt-Mulheim  "),  The  plasma 
obtained  from  such  blood  by  means  of  centrifugal  force  is  called 

1  Du  Bois-Reymond's  Arcbiv,  1881,  S.  377. 
Ubid.,  1880. 

Ill 


1V2  THE  BLOOD. 

^^ pepio7ie-2}las?na.''^  The  coagulation  of  the  blood  of  warm-blooded 
animals  is  prevented  by  the  injection  of  an  effusion  of  the  mouth  of 
the  officinal  leech  into  the  blood-current  (Haycraft').  If  the 
blood-circulation  of  a  dog  is  cut  off  from  the  liver  and  intestine  and 
the  blood  allowed  to  flow  only  through  the  head  and  the  viscera  of 
the  thoracic  cavity,  the  coagulation  property  of  the  blood  is 
destroyed  (Pawlow,  Bohr'^).  The  statement  as  to  the  non- 
coagulability  of  the  blood  after  the  excision  of  the  liver  and 
abnominal  cavity  could  not  be  confirmed  by 'Contejean^/  If  we 
allow  the  blood  to  flow  directly,  while  we  stir  it,  into  a  neutral  salt 
solution — best  a  saturated  magnesium-sulphate  solution  (1  vol.  salt 
solution  and  3  vols,  blood) — we  obtain  a  mixture  of  blood  and  salt 
which  remains  nncoagulated  for  several  days.  The  blood-corpuscles 
which,  because  of  their  adhesiveness  and  elasticity,  would  otherwise 
pass  easily  through  the  pores  of  the  filter-paper  are  made  solid  and 
stiff  by  the  salt,  so  that  they  may  be  easily  filtered.  The  plasma 
thus  obtained,  which  does  not  coagulate  spontaneously,  is  called 
"  salt-jilasma.'''' 

An  especially  good  method  of  preventing  coagulation  of  blood 
consists  in  drawing  the  blood  into  a  dilute  solution  of  potassium 
oxalate,  so  that  the  mixture  contains  0.1^  oxalate  (Arthus  and 
Pages  ^).  The  soluble  calcium  salts  of  the  blood  are  precipitated 
by  the  oxalate,  and  hence  the  blood  loses  its  coagulability. 

On  coagulation  there  separates  in  the  previously  fluid  blood  an 
insoluble  or  a  very  difficultly  soluble  albuminous  substance,  fibrin. 
When  this  separation  takes  place  without  stirring,  the  blood  coagu- 
lates to  a  solid  mass  which,  when  carefully  severed  from  the  sides 
of  the  vessel,  contracts,  and  a  clear,  generally  yellow-colored  liquid, 
the  Uood-serum,  exudes.  The  solid  coagulum  which  encloses  the 
blood-corpuscles  is  called  the  Mood-clot  (placenta  sanguinis).  If  the 
blood  is  beaten  during  coagulation,  the  fibrin  separates  in  elastic 
threads  or  fibrous  masses,  and  the  defihrinated  Mood  which  separates 
is  sometimes  called  cruor^^  and   consists  of  blood-corpuscles  and 

iProc.  physiol.  Soc,  1884,  p.  13,  and  Arcli.  f.  exp.  Pathol,  und  Pliarm., 
1884,  Bd.  18. 

^Centralbl.  f.  Physiol.,  1888,  No.  11. 

^  Arch,  de  Physiol.,  Ser.  5,  Tome  7. 

'^lUd.,  Tome  2,  1890,  and  Compt.  rend.,  1891,  Tome  112,  No.  4. 

*  The  name  cruor  is  used  in  different  senses.  We  .sometimes  understand 
thereby  only  the  blood  when  coagulated  to  a  red  solid  mass,  in  other  cases  the 
blood-clot  after  the  separation  of  the  serum,  and  lastly  the  sediment  consisting 


BLOOD  PLASMA.  113 

Wood-sernm.  Defibrinated  blood  consists  of  blood-corpuscles  and 
serum,  while  uncoagulated  blood  consists  of  blood-corpuscles  and 
blood-plasma.  The  essential  chemical  difference  between  blood- 
serum,  and  blood-plasma  is  that  the  blood-serum  does  not  contain 
the  mother-substance  of  fibrin,  the  fibrinogen,  which  exists  in  the 
blood-plasma,  and  the  serum  is  proportionally  richer  in  another 
body,  the  fibrin  ferment  (see  page  116). 

I.  Bloocl-i>lasiiia  and  Blood-serum. 

The  Blood-plasma. 

In  the  coagulation  of  the  blood  a  chemical  transformation  takes 
place  in  the  plasma.  A  part  of  the  proteids  separates  as  insoluble 
fibrin.  The  albuminous  bodies  of  the  plasma  must  therefore  be  first 
described.  They  are,  as  far  as  we  know  at  present,  fibrinogen, 
serglobulin,  aiid  seralMmm. 

Fibrinogen  occurs  in  blood-plasma,  chyle,  lymph,  and  in  certain 
transudations  and  exudations.'  It  has  the  general  proportie^;  of  the 
globulins,  but  differs  from  other  globulins  as  follows:  In  ii  moist 
condition  it  forms  white  flakes  which  are  soluble  in  dilute  common- 
salt  solutions,  and  which  easily  conglomerate  into  tough,  elastic 
masses  or  lumps.  The  solution  in  XaCl  of  5-10^  coagulates  on 
heating  to  +  52°  to  55°  C,  and  the  faintly  alkaline  or  nearly 
neutral  weak  salt  solution  coagulates  at  -|-  56°  C,  or  at  exactly  the 
same  temperature  at  which  the  blood-plasma  coagulates.  Fibrin- 
ogen solntioas  are  precipitated  by  an  equal  volume  of  a  saturated 
common-salt  soluion,  and  are  completely  precipitated  by  adding  an 
excess  of  XaCl  in  substance  (thus  differing  from  serglobulin).  It 
differs  from  myosin  of  the  muscles,  which  coagulates  at  about  the 
same  temperature,  and  from  other  albuminous  bodies,  in  the 
property  of  being  converted  into  fibrin  under  certain  conditions. 
Fibrinogen  has  a  strong  decomposing  action  on  hydrogen  peroxide.* 
It  is  quickly  made  insoluble  by  precipitation  with  water  or  with 

of  red  blood-corpuscles  which  is  obtained  from  defibrinated  blood  by  means  of 
centrifugal  force  or  by  letting  it  stand. 

'  The  question  as  to  the  occurrence  of  other  fibrinogens  (Wooldridge)  will 
be  spoken  of  in  connection  with  the  complete  discussion  of  the  coagulation  of 
the  blood.     (See  further  on.) 

'  In  regard  to  fibrinogen  the  reader  is  referred  to  the  author's  investigations. 
Pfluger's  Archiv,  Bdd.  19  and  22, 


114  THE  BLOOD. 

dilate  acids.     Its  specific  rotation  is  «'(D)  =  —  52.5°  according  to 

MiTTELBACH. ' 

-Fibrinogen  may  be  easily  separated  from  the  salt-plasma  by  pre- 
cipitation with  an  eqnal  volume  of  a  saturated  JSTaCl  solution.  For 
further  purification  the  precipitate  is  pressed,  redissolved  in  an  8^ 
salt  solution,  the  filtrate  precipitated  by  a  saturated-salt  solution 
as  above,  and  after  precipitating  in  this  way  three  times  the  pre- 
cipitate at  last  obtained  is  pressed  between  filter-paper  and  finely 
divided  in  water.  The  fibrinogen  dissolves  with  the  aid  of  the 
small  amount  of  NaCl  contained  in  itself,  and  the  solution  may  be 
made  salt-free  by  dialysis  with  very  faintly  alkaline  water.  From 
transudations  we  ordinarily  obtain  a  fibrinogen  which  is  strongly 
-contaminated  with  lecithin  and  which  can  hardly  be  purified  with- 
out decomposing.  The  method  for  the  detection  and  quantitative 
estimation  of  fibrinogen  in  a  liquid  is  based  on  its  property  of 
yielding  fibrin  on  the  addition  of  a  little  blood,  of  sernm,  or  of 
fibrin  ferment. 

The  fibrinogen  stands  in  close  relation  to  its  transformation- 
product,  the  fibrin. 

Fibrin  is  the  name  of  that  proteid  body  which  separates  on  the 
so-called  spontaneous  coagulation  of  blood,  lymph,  and  transuda- 
tions, as  also  in  the  coagulation  of  a  fibrinogen  solution  after  the 
addition  of  serum  or  fibrin  ferment  (see  below). 

If  the  blood  is  beaten  during  coagulation,  the  fibrin  separates 
in  elastic,  fibrous  masses.  The  fibrin  of  the  blood-clot  may  be 
beaten  to  small,  less  elastic,  and  not  particularly  fibrous  lumps. 
Tlie  typical,  fibrous,  and  elastic  white  fibrin,  after  washing,  stands 
in  regard  to  its  solubility  close  to  the  coagulated  proteids.  It  is 
insoluble  in  water,  alcohol,  or  ether.  It  expands  in  hydrochloric 
acid  of  1  p.  m.,  as  also  in  caustic  potash  or  soda  of  1  p.  m.,  to  a 
gelatinous  mass,  which  dissolves  at  the  ordinary  temperature  only 
after  several  days,  but  at  the  temperature  of  the  body  it  dissolves 
more  readily  but  still  slowly.  Fibrin  expands  in  a  5-10^  solution 
of  common  salt  or  saltpetre,  but  only  dissolves  very  slowly  at  ordi- 
nary temperature,  while  at  40°  C.  it  dissolves  more  readily.  At 
present  we  cannot  positively  state  what  action  the  presence  of 
micro-organisms  or  contaminating  enzymes  have  on  this  solution. 
According  to  Arthus  and  IIuber,^  and  also  lately  to  Dareste,' 
there  is  no  doubt  of  the  solubility  of  fibrin  in  neutral  salt  solutions 

iZeitschr.  f.  pbysiol.  Chem.,  Bd.  19. 
'Arch,  de  Physiol.,  Ser.  5,  Tome  5. 
^IMd.,  Tome  7. 


FIBRIN.  115 

without  the  action  of  micro-organisms.  According  to  Green  '  two 
globulins  are  formed  in  this  solation  of  fibrin.  Fibrin  decomposes 
hydrogen  peroxide,  but  this  projoerty  is  destroyed  by  heating  or  by 
the  action  of  alcohol. 

What  has  been  said  of  the  solubility  of  fibrin  relates  only  to  the 
typical  fibrin  obtained  from  the  arterial  blood  of  mammals  or  man 
by  whipping  and  washing  first  with  water  and  with  common-salt 
solution,  and  then  with  water  again.  The  blood  of  various  kinds 
of  animals  yields  fibrin  with  somewhat  different  proiJerties,  and 
according  to  Fermi'  pig-fibrin  dissolves  much  more  readily  in 
hydrochloric  acid  of  5  p.  m.  than  ox-fibrin.  Fibrins  of  varying 
purity  or  originating  from  blood  from  different  parts  of  the  body 
have  unlike  solubilities. 

The  fibrin  obtained  by  beating  the  blood  and  purified  as  above 
described  is  always  contaminated  by  enclosed  blood-corpuscles  or 
remains  thereof,  and  also  by  lymphoid  cells.  It  can  only  be 
obtained  pure  from  filtered  plasma  or  filtered  transudations.  For 
the  pure  preparation,  as  well  as  for  the  quantitative  estimation  of 
fibrin,  the  spontaneously  coagulating  liquid  is  at  once,  or  the  non- 
spontaneonsly  coagulating  liquid  only  after  the  addition  of  blood- 
serum  or  fibrin  ferment,  thoroughly  beaten  with  a  whale-bone,  and 
the  separated  coagulum  is  washed  first  in  water,  and  then  with  a  5^ 
common-salt  solution,  and  again  with  water,  and  lastly  extracted 
with  alcohol  and  ether.  If  the  fibrin  is  allowed  to  stand  in  contact 
with  the  blood  from  which  it  was  formed  for  some  time,  it  partly 
dissolves  (fibrinolysis — Dastre  ').  This  fibrinolysis  mast  be  pre- 
vented in  the  quantitative  estimation  of  fibrin  (Dastre). 

A  pure  fibrinogen  solution  may  be  kept  at  the  ordinary  tem- 
perature until  putrefaction  begins  without  showing  a  trace  of  fibrin 
coagulation.  But  if  to  this  solution  we  add  a  water- washed  fibrin- 
clot  or  a  little  blood-serum,  it  immediately  coagulates  and  may 
yield  perfectly  tyj)ical  fibrin.  The  transformation  of  the  fibrinogen 
into  fibrin  requires  the  presence  of  another  body  contained  in  the 
blood-clot  and  in  the  seram.  This  body,  whose  importance  in  the 
coagulation  of  fibrin  was  first  observed  by  Buchanan,*  was  later 
rediscovered  by  Alexander  Schmidt^  and  designated  '■'■  fihrin- 

'  Journal  of  Physiol.,  Vol.  8,  p.  513. 
5  Zeitscbr-  f   Biologic,  Bd.  28,  S.  329. 

« Archives  de  Physiol.  (5),  Tome  5,  No.  3,  and  Tome  6,  No.  4,  p.  670. 
*  London  Med.  Gazette,  1845,  p.  617.     Cit.  by  Qamgee,  Journal  of  Physiol., 
1879. 

spfluger's  Archiv,  Bd.  6,  S.  413. 


116  THE  BLOOD. 

ferment.''''  The  nature  of  this  enzymotic  body  has  not  been  ascer- 
tained. Although  many  investigators,  especially  English,  consider 
fibrin-ferment  as  a  globulin,  still  more  recent  experiments  of 
Pekelharing,'  Wright,'  and  Lilienfeld'  show  that  it  is  a 
nncleoalbumin  or  perhaps  a  nucleoproteid.  Fibrin  ferment,  which 
is  now  called  thrombin  by  Alex.  Schmidt,"  is  produced,  according 
to  Pekelharin^g,  by  the  action  of  soluble  calcium  salts  on  a  pre- 
formed zymogen  existing  in  the  non-coagulated  plasma.  Schmidt 
admits  of  the  presence  of  such  a  mother-substance  of  the  fibrin 
ferment  in  the  blood  and  calls  it  prothrombin.  The  zymogen  as 
well  as  the  fibrin  ferment  is  less  soluble  in  an  excess  of  acetic  acid 
than  the  globulins,  and  yields  a  nuclein  or  a  pseudonuclein  on  peptic 
digestion.  Thrombin  corresponds  to  other  enzymes  in  that  the  very 
smallest  amount  of  it  produces  an  action  and  its  solution  becomes 
inactive  on  heating.  It  is  most  active  at  about  40°  C.  The 
zymogen,  according  to  Pekelharing,  is  destroyed  at  about 
+  65°  C,  while  the  ferment  is  destroyed  at  about  the  same  or  a 
little  higher  temperature,  70-75°  0. 

The  isolation  of  the  fibrin-ferment  has  been  tried  in  several 
ways.  Ordinarily  it  may  be  prepared  by  the  following  method  pro- 
posed by  Alex.  Schmidt^:  Precipitate  the  serum  or  defibrinated 
blood  with  15-20  vols,  of  alcohol  and  allow  it  to  stand  a  few 
months.  The  precipitate  is  then  filtered  and  dried  over  sulpharic 
acid.  The  ferment  may  be  extracted  from  the  dried  powder  by 
means  of  water. 

A  globulin-free  thrombin  solution  may  be  prepared  as  follows, 
according  to  the  author^:  The  globulins  are  sejDarated  from 
ox-serum  by  completely  saturating  with  magnesium  sulphate,  filter- 
ing and  diluting  the  filtrate  with  water,  and  then  adding  very  dilute 
caustic-soda  solution,  with  constant  stirring  until  a  rather  abundant, 
flocky  precipitate  of  Mg(0H)2  is  obtained.  This  precipitate,  which 
contains  a  great  deal  of  the  ferment,  is  washed,  pressed,  dissolved 
in  water  with  the  aid  of  acetic  acid  until  neutral,  and  then  freed 
from  salts  by  means  of  dialysis. 

'  Verhandel.  d.  kon.  Akad.  d.  Wetenscli.  te  Amsterdam,  Deel  1,  No.  3,  1892. 

^  Proc.  of  Eoy.  Irish  Acad.  (3),  Vol.  3,  and  Lecture  on  Tissue-  or  Cell-fibrin- 
ogen,  Lancet,  1892;  also  on  Wooldridge's  Method,  etc.,  British  Med.  Journal, 
Sept.;  1891. 

^  Du  Bois-Reymond's  Archiv,  1892,  and  Ueber  Leukocyten  und  Blutgerin- 
nung,  Verhandl.  d.  physiol.  Gesellsch.  zu  Berlin,  1893. 

4  Zur  Blutlehre.     Leipzig,  1892. 

'PflUger's  Archiv,  Bd.  6. 

^lUd.  Bd.  18,  S.  89. 


CO  A  O  ULA  TION,  117 

Thrombin  can  be  precipitated  from  this  sohition,  according  to 
Pekelharing,'  by  the  proper  addition  of  acetic  acid.  According 
to  this  investigator,  it  is  best  to  dialyze  the  above  filtrate  saturated 
with  MgSO^  and  then  precipitate  with  acetic  acid.  He  has  been 
able  to  obtain  thrombin  directly  from  the  blood-serum  by  diluting 
with  water  and  adding  acetic  acid  until  the  serglobulin,  which  first 
jjrecipitates,  is  at  least  in  great  part  redissolved.  The  thrombin  is 
purified  by  repeated  solution  in  alkaline  water  and  reiorecipitating 
with  acetic  acid. 

If  a  fibrinogen  solution  containing  salt,  as  above  jirepared,  is 
treated  with  a  solution  of  "  fibrin-ferment,"  it  coagulates  at  the 
ordinai'y  temperature  more  or  less  quickly  and  yields  a  typical  fibrin. 
Besides  the  fibrin  ferment  the  i^resence  of  neutral  salts  is  necessary, 
for  without  them  Alex.  Schmidt"  has  shown  the  coagulation  of 
fibrin  does  not  take  place.  The  presence  of  soluble  calcium  salts  is 
likewise  an  essential  condition  for  the  formation  of  fibrin  (Arthus 
and  Pages,  Pekelharing),  and  the  fibrin  separated  always  con- 
tains calcium.  The  quantity  of  fibrin  obtained  on  coagulation  is 
always  smaller  than  the  amount  of  fibrinogen  from  which  the  fibrin 
is  derived,  and  we  always  find  a  small  amount  of  protein  substance 
in  the  solution.  It  is  therefore  not  improbable  that  the  coagulation 
of  fibrin,  in  accordance  with  the  views  of  Denis,  is  a  splitting 
process  in  which  the  soluble  fibrinogen  is  split  into  an  insoluble 
albuminous  body,  the  fibrin,  which  forms  the  chief  mass,  and  a 
soluble  protein  substance  which  is  only  formed  in  small  amounts. 
We  find  a  globulin-like  substance  which  coagulates  at  about 
-|-  64°  C.  in  blood-serum  as  well  as  in  the  serum  from  coagulated 
fibrinogen  solutions.  This  substance  is  csklled  fibrin-fflobulin  by  the 
AUTHOR.^  The  question  whether  this  substance  exists  in  the 
fibrinogen  solution  as  contamination  or  is  formed  as  a  sjilitting 
product  has  not  been  positively  decided. 

The  lime-salts,  as  above  stated,  are  a  necessary  factor  in  the 
coagulation.  According  to  Pekelharing,"  they  act  as  follows: 
The  fibrin-ferment  or  thrombin  is  a  calcium  combination  of  the 
zymogen,  the  prothrombin.  In  coagulation  the  calcium  is  trans- 
ferred to  the  fibrinogen  by  the  thrombin,  forming  insoluble  fibrin 
containing   calcium.     The    thrombin   is   hereby  reconverted   into 

^L.  c. 

"Pfiilger's  Archiv,  Bd.  11,  S.  291-304  ;  also  Bd.  13,  S.  103. 

s  Ibid.,  Bd.  23. 

"» Verhandel.  d.  kon.  Akad.  d.  Wettensch.  te  Amsterdam,  Deel  1,  No.  3,  1893. 


118  THE  BLOOD. 

prothrombin,  whicli  takes  up  more  calcium,  being  converted  into 
thrombin  again,  which  then  gives  np  its  calcium  to  a  new  portion 
of  fibrinogen,  and  so  on.  The  process  has  great  similarity  to  the 
formation  of  ether  from  alcohol  by  sulphuric  acid. 

LiLiENFELD '  has  described  his  experiments  and  views  in  an 
extensive  memoir.  According  to  him  the  fibrinogen  may  be  split 
by  acetic  acid,  and  also  by  the  nuclein  substances  of  the  leucocytes 
(these  also  act  in  alkaline  solution),  into  a  proteid  body,  which  is 
precipitated  readily,  tlirovibosin^  and  an  albumose-like  substance, 
which  gives  the  biuret  reaction  and  which  retards  coagulation. 
Thrombosin  passes  into  fibrin  in  the  presence  of  soluble  calcium 
salts,  without  further  addition  inasmuch  as  fibrin  is  nothing  but 
the  calcium  combination  of  thrombosin.  The  above  cleavage  of 
fibrinogen  into  thrombosin  and  a  soluble  proteid  substance  may  also 
take  place  in  the  absence  of  calcium  salts,  and  these  are  only  neces- 
sary for  the  separation  of  the  calcium  combination  of  thrombosin, 
i.e.,  fibrin.  Fibrin-ferment,  which  is  a  globulin  according  to 
LiLiESTFELD,  is  not  a  precursor  but  a  product  of  the  coagulation. 
The  coagulation  process  is  considered  by  Lilienfeld  and  most 
investigators  as  a  cleavage  of  the  fibrinogen,  and  the  essential 
difference  between  his  theory  and  the  others  consists  in  that  the 
coagulation  exciter  is  not  the  fibrin-ferment  but  a  nucleoproteid 
which  is  the  leuconuclein  derived  from  the  nucleohiston  by  cleavage. 

Hallibukton"  and  Brodie  °  have  raised  an  objection  to  the 
statement  of  Pekelharing  as  to  the  identity  of  fibrin-ferment  with 
a  nucleoproteid  or  its  calcium  combination  occurring  in  the  blood- 
plasma.  PekelharIjSTG  '  has  repudiated  this  in  a  recent  article. 
He  has  shown,  in  opposition  to  the  views  of  Halliburton  and 
LilieinTfeld,  that  the  fibrin-ferment  yields  nuclein  in  careful  pepsin 
digestion,  hence  it  must  be  a  nucleoproteid.  In  a  work  which 
appeared  after  the  death  of  Alex.  Schmidt'  he  has  given  his 
position  on  the  work  of  other  investigators  in  this  field,  but  as 
this  extensive  work  is  chiefly  of  a  critical  nature  we  cannot 
discuss  it. 

According  to  Dogiel  and  Holzmann  ^  the  fibrin  coagulation 

'Zeitschr.  f.  physiol.  Chem.,  Bd.  20. 
i*  Jouraal  of  Physiol  ,  Vol.  17. 
sCentralbl.  f.  Physiol.,  1895,  Heft  3. 
*  Weitere  Beitrage  zur  Blutlehre.     Wiesbaden,  1895. 

'  Compt.  rend.  d.  congres  internat.  des  sciences  medicales  d  Copenhague, 
1884,  Tome  1,  p.  135. 


SERG  L  OB  ULIN.  1 1 9 

consists  in  an  oxidation  of  fibrinogen.  The  relationship  of  oxygen 
to  the  coagulation  is  indeed  not  clear,  and  that  it  has  a  certain  influ- 
ence on  the  coagulation  cannot  be  denied;  still,  as  coagulation  may 
take  place  in  the  absence  of  free  oxygen,  the  above  view  does  not 
seem  to  be  based  on  sufficient  fact. 

Although  the  processes  of  coagulation  are  still  not  clear,  never- 
theless they  consist  essentially  in  the  conversion  of  the  fibrinogen 
of  the  plasma  into  fibrin.  The  coagulation  of  the  blood  is  a  much, 
more  complicated  process  than  the  coagulation  of  a  fibrinogen  solu- 
tion, inasmuch  as  the  first  involves  other  important  questions,  as, 
for  instance,  the  reason  for  the  blood  remaining  fluid  in  the  body, 
the  origin  of  the  fibrin-ferment,  and  the  importance  of  the  form- 
elements  in  the  coagulation.  A  fuller  discussion  of  the  various 
hypotheses  and  theories  concerning  the  coagulation  of  the  blood 
must  therefore  be  given  later. 

Serglobulin,  also  called  paraglobulin  (Kuhne  '),  Jihrinoplastic 
substance  (Alex.  Schmidt'),  serum-casein  (Panum^),  occurs  in 
the  plasma,  serum,  lymph,  transudations  and  exudations,  in  the 
white  and  red  corpuscles,  and  probably  in  many  animal  tissues  and 
form-elements,  though  in  small  quantities.  It  is  also  found  in  the 
urine  in  many  diseases. 

Serglobulin  is  without  doubt  not  an  individual  substance,  but 
consists  of  a  mixture  of  two  or  more  protein  bodies  which  cannot 
be  completely  and  positively  separated  from  each  other.  Under 
these  circumstances  the  statements  in  regard  to  the  properties  of 
the  serglobulins  is  naturally  somewhat  uncertain.  According  to 
onr  present  knowledge  it  has  the  following  properties:' 

Serglobulin  has  the  general  properties  of  the  globulins.  In  a 
moist  condition  it  forms  a  snow-white  flaky  mass  neither  tough  nor 
elastic.  The  essential  differences  between  serglobulin  and  fibrinogen 
are  the  following:  Serglobulin  solutions  are  only  incompletely  pre- 
cipitated by  adding  XaCl  to  saturation,  and  not  precipitated  at  all 
by  an  equal  volume  of  a  saturated  common-salt  solution.  The 
coagulation  temperature  is,  with  5-10^  XaCl  in  solution,  +  75°  C. 
It  is  completely  precipitated  by  MgSO^  in  substance  added  to  sat- 
uration,  as  also  by  an  equal  volume  of  a  saturated  solution  of 

'  Lebrbucli  d.  physiol.  Cliem.     Leipzig,  1866-68. 

*Arcb.  f.  Anat.  u.  Physiol..  1861,  S.  545,  and  1862,  S.  428. 

*  Virchow's  Arcliiv,  Bd.  4. 

*See  Hammarsten ,  Ueber  Paraglobulin,  Ptluger's  Arcliiv,  Bdd.  17  and  18. 


120  THE  BLOOD. 

ammonmm  sulphate.  The  specific  rotatory  power,  according  to 
FfiEDEEiCQ,'  for  serglobulin  (from  ox-blood)  solutions  containing 
salt  is  a{D)  =  -  47.8°. 

According  to  K.  Moristee  °  serglobulin  yields  a  reducing  sub- 
stance on  boiling  with  a  dilute  acid.  The  question  whether  the 
substance  we  have  heretofore  called  serglobulin  is  a  glycoproteid  or 
whether  it  is  a  mixture  of  globulin  with  a  glycoproteid  has  not  been 
positively  decided  up  to  the  present  time. 

Serglobulin  may  be  easily  separated  as  a  fine  floccnlent  precipi- 
tate from  blood-serum  by  neutralizing  or  making  faintly  acid  with 
acetic  acid  and  then  diluting  with  10-20  yoIs.  of  water.  For 
further  purification  this  precipitate  is  dissolved  in  dilute  common- 
salt  solution,  or  in  water  by  the  aid  of  the  smallest  possible  amount 
of  alkali,  and  then  reprecipitated  by  diluting  with  water  or  by  the 
addition  of  a  little  acetic  acid.  The  serglobulin  may  also  be 
separated  from  the  serum  by  means  of  magnesium  or  ammonium 
sulphate;  in  these  cases  it  is  difficult  to  completely  remove  the  salt 
by  dialysis.  The  serglobulin  from  blood-serum  is  always  contami- 
nated by  lecithin  and  so-called  fibrin-ferment.  A  serglobulin 
free  from  fibrin-ferment  may  be  prepared  from  ferment-free  transu- 
dations, as  sometimes  from  hydrocele  fiuids,  and  this  shows  that 
serglobulin  and  fibrin-ferment  are  different  bodies.  For  the  detec- 
tion and  the  quantitative  estimation  of  serglobulin  we  may  use  ■ 
the  precipitation  by  magnesium  sulphate  added  to  saturation 
(author  ),  or  by  an  equal  volume  of  a  saturated  neutral  ammonium 
sulphate  solution  (Hofmeister  and  Kauder  and  Pohl^).  In  the 
quantitative  estimation  the  precipitate  is  collected  on  a  weighed 
filter,  washed  with  the  salt  solution  employed,  dried  with  the  filter 
at  about  115°  C,  then  washed  with  boiling-hot  water,  so  as  to 
completely  remove  the  salt,  extracted  with  alcohol  and  ether,  dried, 
weighed  and  burnt  to  determine  the  ash. 

Seralbumin  is  found  in  large  quantities  in  blood-serum,  blood- 
plasma,  lymph,  transudations,  and  exudations.  Probably  it  also 
-occurs  in  other  animal  liquids  and  tissues.  The  proteids  which 
pass  into  the  urine  under  pathological  conditions  consists  largely  of 
seralbumin. 

In  the  dry  state  seralbumin  forms  a  transparent,  gummy,  brittle, 
hygroscopic  mass,  or  a  white  j)owder  which  may  be  heated  to 
100°  0.   without  decomposing.     Its  solution  in  water  gives  the 

» Bull.  Acad.  Roy.  de  Belg.  (2),  Tome  50. 

"Centralbl.  f.  Physiol.,  1893,  No.  20. 

3  Pfluger's  ArcMv,  Bd.  17,  S.  447. 

^Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  20,  S.  411  and  436. 


SERALBUMIN.  121 

ordinary  reactions  for  albumins;  the  specific  rotatory  power  for 
seralbumin  free  from  paraglobulin,  obtained  from  human  transuda- 
tions, is,  according  to  Stark,'  oc(D)  =  —  62.6°  to  —  64.6°.  The 
coagulation  temperature  of  a  seralbumin  solution  is  +  70°  to 
-j-  75°  C,  according  to  most  authorities,  but  this  varies  to  a  great 
extent  with  a  varying  concentration  and  amount  of  salt  (Stark). 
A  1-3^  seralbumin  solution  may,  in  the  presence  of  very  little 
NaOl,  coagulate  at  +  50°  C.  or  below;  in  the  presence  of  5^  NaCI 
it  coagulates  at  -f-  75°  to  +  90°  C.  By  the  careful  addition  of  acid 
the  coagulation  temperature  maybe  lowered;  by  the  addition  of 
alkali  it  may  be  raised.  In  blood-serum  from  certain  animals  and 
inhuman  transudations  Halliburtojst '^  found  the  coagulation  to 
take  place  on  heating  to  the  following  temperatures:  -(-  70°  to 
73°  C. ;  77°  to  78°  C. ;  and  82°  to  85°  C.  He  therefore  considers 
the  seralbumin  as  a  mixture  of  three  albumins,  ex,  /?,  and  y,  which 
coagulate  at  the  three  points  mentioned.  In  cold-blooded  animals 
he  found  only  the  <a'-albumiu.  Gurber  "  has  prepared  crystallized 
proteid  from  blood-serum  of  the  horse,  which  seems  to  correspond 
to  three  different  seralbumins. 

Seralbumin  differs  from  the  albumin  of  the  white  of  the  hen's 
egg  in  the  following  particulars:  it  is  more  Isev^ogyrate;  the  precipi- 
tate formed  by  hydrochloric  acid  easily  dissolves  in  an  excess  of  the 
acid;  is  rendered  less  insoluble  by  alcohol;  and  lastly  it  acts  dif- 
ferently inside  of  the  organism.  If  egg-albumin  is  introduced  into 
the  blood  system  it  passes  into  the  urine,  while  seralbumin  does 
not.  A  solution  of  seralbumin  positively  free  from  mineral  bodies 
has  never  yet  been  prepared.  A  solution  as  poor  as  possible  in  salts 
does  not  coagulate  either  on  boiling  or  on  the  addition  of  alcohol. 
After  the  addition  of  a  little  common  salt  it  coagulates  in  both 
cases. 

In  preparing  seralbumin,  first  remove  the  globulins  according 
to  Johansson,'  by  saturating  with  magnesium  sulphate  at  about 
-f  30°  C,  and  filtering  at  the  same  temperature.  The  cooled 
filtrate  is  separated  from  the  crystallized  salt  and  is  treated  with 
acetic  acid  so  that  it  contains  about  Ifo.  The  precipitate  formed  is 
filtered,  pressed,  dissolved  in  water  with  the  addition  of  alkali  to 
neutral  reaction,  and  the  solution  freed  from  salt  by  dialysis.     The 

'  Maly's  Jabresbericht,  Bd.  11, 

^Journal  of  Pbysiol..  Vols.  5  and  7. 

•Sitzungsber.  d.  Wiirzb.  pbys.  med.  Gesellscb.,  1894. 

*Zeitscbr.  f.  physiol.  Cheui.,  Bd.  9,  S.  317. 


122  THE  BLOOD. 

seralbumin  may  also  be  separated  from  the  filtrate  saturated  with 
magnesium  sulphate  by  adding  sodium  sulphate  to  saturation  at 
about  +  40°  C.  (Staek').  The  pressed  precipitate  is  also  in  this 
case  dissolved  in  water  and  the  solution  freed  from  salt  by  dialysis. 
The  albumin  may  be  obtained  in  a  solid  form  from  the  dialyzed 
solution  either  by  evaporating  the  solution  to  dryness  at  gentle  heat 
or  by  precipitating  with  alcohol,  which  must  be  removed  quickly. 
In  the  detection  and  quantitative  estimation  of  seralbumin,  the 
filtrate  from  the  globulins  which  have  been  removed  by  magnesium 
sulphate  is  heated  to  boiling,  after  the  addition  of  a  little  acetic  acid 
if  necessary.  The  simplest  way  is  to  consider  the  difference  between 
the  total  proteids  and  the  globulins  as  seralbumin. 

Summary  of  the  elementary  composition  of  the  above  mentioned  and 
described  albuminous  bodies  : 

C  H  N             S  O 

Fibrinogen , 52.93  6.90  16.66  1.25  22.26  (Hammaksten) 

Fibrin 52.68  6.83  16.91  1.10  22.48 

Fibrin-globulin. 52.70  6.98  16.06          

Serglobulin 52.71  7.01  15.85  1.11  23.32 

Seralbumin  (1) 53.06  6.85  16.04  1.80  22.26 

Seralbumin  (2) 52.25  6.65  15.88  2.25  22.97 

The  seralbumin  (2)  came  from  a  human  exudatten,  and  the  other  bodies 
from  horse  s  blood.  The  fibrin  was  prepared  from  a  filtered  common-salt 
plasma. 

The  Blood-serum. 

As  above  stated,  the  blood-serum  is  the  clear  liquid  which  is 
pressed  out  by  the  contraction  of  the  blood-clot.  It  differs  chiefly 
from  the  plasma  in  the  absence  of  fibrinogen  and  an  abundance  of 
fibrm-ferment.  Considered  qualitatively  the  blood-serum  contains 
the  same  chief  constituents  as  the  blood-plasma. 

Blood-serum  is  a  sticky  liquid  which  is  more  alkaline  than  the 
plasma.  The  specific  gravity  in  man  is  1.027  to  1.032,  average 
1.028,  The  color  is  strongly  or  famtly  yellow;  in  human  blood- 
serum  it  is  pale  yellow  with  a  shade  towards  green,  and  in  horses  it 
is  often  amber-yellow.  The  serum  is  ordinarily  clear;  after  a  meal 
it  may  be  opalescent,  cloudy,  or  milky  white,  according  to  the 
amount  of  fat  contained  in  the  food. 

Besides  the  above-mentioned  bodies,  the  following  constituents 
are  found  in  the  blood-plasma  or  blood-serum : 

Fat  occurs  from  1-7  p.  m,  in  fasting  animals.     After  partaking 

'Maly's  Jahresber.,  Bd.  11. 


GLUCOSE  AND   GLYCOLYSIS.  123 

of  food  the  amount  is  increased  to  a  great  extent.  We  also  find 
soaps  (Hoppe-Seyler '),  cholesterin,  and  lecithin. 

Glucose  seems  to  be  a  physiological  constituent  of  the  plasma. 
According  to  the  investigations  of  Abeles,  Ewald,  Kulz, 
V.  Merixg/  and  Seegen,"  the  sugar  found  in  the  plasma  is 
glucose.  Otto  '  found  in  the  plasma,  besides  glucose,  another 
reducing,  non-fermentable  substance.  The  amount  of  glucose  in 
the  blood  is  about  1-1.5  p.  m.  Otto  found  in  human  blood  1.18 
p.  m.  glucose  and  0.29  p.  m.  of  the  other  reducing  substance. 
According  to  Jacobsex,"  this  is  soluble  in  ether  and  is  closely 
related  to  jecorin.  The  amount  of  glucose  in  the  blood  seems  to 
be  almost  independent  of  the  food,  nevertheless  after  feeding  with 
large  quantities  of  glucose  and  dextrin  Bleile"  observed  a  signifi- 
cant increase  of  glucose.  If  the  amount  is  more  than  3  p.  m., 
according  to  Cl.  Berxard,'  the  glucose  passes  into  the  urine,  pro- 
ducing glycosuria.  The  different  amounts  of  glucose  in  tbe  blood 
from  different  vessels  and  under  various  conditions  will  be  fully 
discussed  later.  The  glycogen  found  m  the  blood  does  not  seem 
to  come  from  the  plasma,  but  from  the  leucocytes. 

Berxard"  has  shown  that  the  quantity  of  sugar  in  the  blood 
diminishes  more  or  less  rapidly  on  leaving  the  veins.  Lepine,* 
associated  with  Barral,  has  specially  studied  this  decrease  in  the 
quantity  of  sugar  and  calls  it  glycolysis.  Lepixe  and  Barral  as 
well  as  Arthus  '°  have  shown  that  this  glycolysis  takes  place  in  the 
complete  absence  of  micro-organisms."     It  seems  to  be  due  to  a 

=  Zeitscbr.  f.  physiol.  Cliem.,  Bd.  8. 

^  Du  Bois-Reymond's  Arcbiv,  1877,  S.  379.  This  article  contains  numerous 
references. 

^  Pfliiger's  Archiv,  Bd.  40. 

*Ibid.,  Bd.  35.  Contains  a  good  review  of  the  literature  of  sugar  in  the 
blood. 

^Centralbl.  f.  Physiol.,  1892,  Part  13, 

6Du  Bois-Reymonds  Arcbiv,  1879,  S.  67-69. 

'  Le9ons  sur  le  diab^te.     Paris,  1877. 

8  Ibid. 

'Lyon  medical.  Tome  62  and  63  ,  Compt.  rendus.  Tome  110,  112,  and  113  ; 
Lepine,  Le  ferment  glycolytique  et  la  patbogenie  du  diab^te  (Paris,  1891),  and 
Revue  analytique  et  critique  des  travaux,  etc.,  in  Arch,  de  med.  exper.  (Paris, 
1892). 

lOArcb.  de  Physiol.,  July  1891  and  April  1892. 

'^  A  critical  review  of  tbe  various  methods  of  removing  proteids  from  tbe 
blood  in  sugar  estimations  is  given  by  Seegeu,  Centralbl.  f.  Physiol.,  1892, 
Heft  17. 


124  THE  BLOOD. 

soluble  enzyme  whose  activity  is  destroyed  by  beating  to  +  54°  C. 
This  enzyme  is  derived,  according  to  the  above  investigators,  from 
the  lencocytes  and  is,  according  to  Lepiiste,  delivered  from  the 
pancreas  to  the  blood.  According  to  LEPii^fE'  the  pancreas  con- 
tains a  zymogen  of  the  glycolytic  enzyme  occurring  in  the  blood. 
This  zymogen,  which  is  converted  into  the  enzyme  by  the  action  of 
sulphuric  acid  of  2  p.  m.  at  38°  C,  is  nothing  but  the  diastatic 
enzyme.  Rohmann  and  Spitzer^  and  Spitzee,'  who  have  shown 
the  occurrence  of  a  glycolysis  under  the  influence  of  not  only  the 
blood  but  also  various  tissues,  consider  this,  as  first  shown  by 
Kraus,'  a  process  of  oxidation.  This  oxidation  is  brought  about 
by  the  oxygen  of  the  oxidation  ferment  occurring  in  the  form- 
elements.  According  to  Arthus  and  CoLENBRAifDER  ^  this  gly- 
colysis is  only  a  post-mortem  process  and  not  a  vital  one. 

Blood-piasma  contains  an  enzyme  which  converts  starch  and 
glycogen  into  sugar  (Rohmaxn*  and  Bial').  This  enzyme  also 
occurs  in  the  lymjDh,  but  not  in  the  form-elements  of  the  blood. 

The  sugar  found  in  the  serum  by  enzyme  action  is  partly  maltose 
or  isomaltose  and  partly  dextrose.  These  various  sugars  are  pro- 
duced in  differing  quantities  in  the  various  phases  of  the  enzymotic 
processes.  This  is  accounted  for,  by  recent  researches  of  EoHMANif 
and  C.  Hamburger,"  by  the  presence  of  two  differing  enzymes  in 
the  blood.  One  of  these  enzymes  is  diastase,  which  converts  starch 
and  glycogen  into  maltose.  The  other  differs  from  invertin  and, 
according  to  Eohmanist,  is  probably  an  enzyme,  identical  with 
glncase,  occurring  in  the  plant  kingdom,  and  which  has  the  prop- 
erty of  splitting  maltose  mto  dextrose. 

Among  the  bodies  which  are  found  in  the  blood,  and  without 
doubt  met  with  in  smaller  or  greater  amounts  in  the  plasma,  are  to 
be  mentioned  urea,  uric  acid  (found  in  human  blood  by  Abeles  ^), 

1  Compt.  rend.,  Tome  120. 

''Ber.  d.  deutscli.  chem.  Gesellscli.,  Bd.  28. 

^  Pfliiger's  Arcliiv,  Bd.  60. 

4Zeitscbr.  f.  klin.  Med.,  Bd.  21. 

*  Maly's  Jaliresber.,  Bd.  32. 

*  Ber.  d.  deutscli.  cliem.  Gesellsch.,  Bd.  25,  and  Pfliiger's  Arch.,  Bd.  52. 

''  Ueber  das  diastatiscbe  Ferment  des  Lymph-  und  Blutserums.  Inaug. 
Diss.  Breslau,  1892.  Contains  also  the  older  literature.  See  also  Pfliiger's 
Arch. ,  Bdd.  52,  54,  and  55. 

8  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  27,  and  Pfliiger's  Arch.^  Bd.  60. 

»  Wien.  mad.  Jahrbucher,  1887. 


EXTRA  CTI VE8.  125 

ceratin,  carbamic  acid,  paralactic  acid,  and  hippuric  acid.  The 
quantity  of  xirea  depends  upon  the  nutritive  condition  of  the 
animal.  During  starvation  Schondorff  '  found  a  minimum  of 
0.348  p.  m.,  and  in  the  highest  stages  of  urea  formation  a  maximum 
of  1.529  p.  m.  Under  pathological  conditions  the  following  bodies 
have  been  found:  xanthin  bases,  leucm,  tyrosin,  and  biliary  con- 
stituents. 

The  coloring  matters  of  the  blood-serum  are  very  little  known. 
In  equine  blood-serum  biliary  coloring  matters,  bihrubin,  besides 
other  coloring  matters,  often  occur.  The  yellow  coloring  matter 
of  the  sernm  seems  to  belong  to  the  group  of  luteins,  which  are 
often  called  lipochromes  or  fat-coloring  matters.  From  ox-serum 
Kuukexberg'  was  able  to  isolate  with  amyl  alcohol  a  so-called 
lipoclirome  whose  solution  shows  two  absorption-bands,  of  which 
one  encloses  the  line  F  and  the  other  lies  between  F  and  G. 

The  mineral  bodies  in  sernm  and  plasma  are  qualitatively,  but 
not  quantitatively,  the  same.  A  part  of  the  calcium,  magnesium, 
and  phosphoric  acid  is  removed  on  the  coagulation  of  the  fibrin. 
By  means  of  dialysis,  the  presence  of  sodium  chloride,  which  forms 
the  chief  mass  or  60-70/^  of  the  total  mineral  bodies,  also  lime- 
salts,  sodium  carbonate,  besides  traces  of  sulphuric  and  phosphoric 
acids  and  potassium,  may  be  directly  shown  in  the  serum.  Traces 
of  silicic  acid,  fluorine,  copper,  iron,  manganese,  and  ammonia  are 
claimed  to  have  been  found  m  the  serum.  As  in  most  animal 
fluids,  the  chlorine  and  sodium  are  in  the  blood-serum  in  excess  of 
the  phosj)horic  acid  and  potassium  (the  occurrence  of  which  in  the 
serum  is  even  doubted).  The  acids  found  in  the  ash  are  not  suffi- 
cient to  saturate  the  bases  found,  a  condition  which  shows  that  a 
part  of  the  bases  is  combined  with  organic  substances,  perhaps 
proteids. 

The  gases  of  the  blood-serum,  which  consist  chiefly  of  carbon 
dioxide  with  only  a  little  nitrogen  and  oxygen,  will  be  described 
when  treating  of  the  gases  of  the  blood. 

Because  of  the  difficulty  of  obtaining  plasma  only  a  few  analyses 
have  been  made.  As  an  example  the  results  of  the  analyses  of  the 
blood-plasma  of  the  horse  will  be  given  below.  The  analysis  No.  1 
was  made  by  Hoppe-Seyler.'     No.  2  is  the  average  of  the  results 

'  Pfliiger's  Arcliiv,  Bd.  54. 

»  Sitzber.  d.  Jen.  Gesellsch.  f.  Med.,  1885. 

'  Cit.  from  V.  Gorup-Besanez's  Lehrbucli  derphysiol.  Chem.,  4.  Aufl.,  p.  346. 


126 


THE  BLOOD. 


of  three  analyses  made  by  the  author.'     The  figures  are  given  in 
1000  parts  of  the  plasma. 

No.  1.  No.  2. 

Water 908.4  917.6 

Solids 91.6  82.4 

Total  proteids 77.6  69.5 

Fibrin 10.1  6.5 

Globulin 38.4 

Seralbumin 24 . 6 

Fat 1.21 

Extractive  substances 4.01  loq 

Soluble  salts 6.4  [  ^'^'^ 

Insoluble  salts l-'J'J 

As  an  example  of  the  composition  of  blood-sernm  with  special 
regard  to  the  relationship  of  the  difEerent  proteids  to  each  other, 
the  following  analyses  are  given.     The  results  are  in  1000  parts. 


Serum 
from 

Solids. 

Total 
Albumin- 
ous 
Bodies. 

Ser- 
globulin. 

Ser- 
albumin. 

Lecithin, 

Fat, 
Salts,  etc. 

Ser- 
globulin 

Ser- 
albumin. 

Authority. 

Man  .  . . 
Horse . . 
Ox 

Dog.... 
Hen.... 
Frog . . . 
Eel  ... . 

92.07 

85.97 
89.65 

54.00 

76.20 
72.57 
74.99 
58.20 
39.49 
25.40 
67.30 

31.04 
45.65 
41.69 
20.50 
7.84 
21.80 
52.80 

45.16 
26.92 
33.30 
37.70 
31.65 
3.60 
14.50 

15.88 
13.40 
14.66 

14.51 

1 

1.5 

1 

0.591 

1 
0.842 

1 
1.8 

1 
4.03 

1 
0.165 

1 
0.275 

Hammaksten  "^ 

Salvioli 2 

Hammarsten 

Halliburton* 

According  to  Halliburton,  the  amount  of  the  albumins  in 
comparison  with  the  globulins  in  cold-blooded  animals  is  not  only 
proportionally  smaller,  bat  the  total  amount  of  albuminous  bodies 
is  smaller  than  in  the  warm-blooded  animals. 

By  a  comparative  investigation  of  serum  and  plasma  from  the 
same  individual,   we  find    more   serglobulin   in  the   one  than   in 


'  Pfiiiger's  Archiv,  Bd.  17. 

*  Ibid. 

»Du  Bois-Reymond's  Archiv,  1881,  S.  275. 

<  Journ.  of  Physiol.,  Vol.  7,  pp.  319-321. 


MINERAL    CONSTITUENTS.  127 

the  other.  The  reason  for  this  may  lie  partly  in  the  fact  that  in 
the  coagnlation  of  hbrin  from  the  fibrinogen  some  fibrin-globulin  is 
formed  which  in  the  quantitative  estimation  is  precipitated  with  the 
serglobulin,  and  partly  because  the  white  corpuscles  yield  serglobu- 
lin  in  the  fibrin  coagulation  (Alex.  Schmidt). 

The  quantity  of  mineral  bodies  in  the  serum  has  been  deter- 
mined by  many  investigators. 

The  conclusions  drawn  from  the  analyses  is  that  there  exists  a 
rather  close  correspondence  between  human  and  animal  blood- 
serum,  and  it  is  therefore  sufficient  to  give  here  the  analysis  of 
C.  Schmidt'  of  (1)  human  blood,  and  of  (2)  pig-  and  (3)  ox-blood 
by  BuifGE.^  As  in  the  calcination  of  lecithin  and  proteids  incor- 
rect results  are  obtained  for  the  phosphoric  and  sulphuric  acids, 
these  results  will  not  be  given  below.  All  figures  correspond  to 
1000  parts  of  serum. 

1 

KjO 0.387-0.401 

Na,0 4.290-4.290 

CI 3.565-3.659 

CaO 0.155-0.155 

MgO 0.101 

Fe,03 

The  amount  of  NaCl  is  about  6  p.  m.,  and  it  is  remarkable  that 
this  amount  of  NaCl  remains  almost  constant,  so  that  with  food 
containing  an  excess  of  NaCl  it  is  quickly  eliminated  by  the  nrine, 
and  with  food  poor  in  chlorides  the  amount  in  the  blood  first 
decreases,  but  increases  after  taking  chlorides  from  the  tissues.  The 
secretion  of  chlorides  by  the  nrine  is  thereby  diminished. 

The  amount  of  phosphoric  acid,  calculated  as  Na^HPO^,  in  the 
serum  freed  from  lecithin  has  been  determined  as  0.02-0.09  p.  m. 
by  Sertoli'  and  Mroczkowski *  in  different  varieties  of  serum. 
The  small  amount  of  iron  sometimes  found  in  the  serum  probably 
originates  from  a  contamination  with  the  blood-coloring  matters. 

'  Cit.  Hoppe-Seyler's  Physiol.  Chem.,  1881,  S.  439. 
»  Zeitschr.  £.  Biologic,  Bd.  12,  S.  206-208. 
'  Hoppe-Seyler's  Med.  chem.  Untersuch.,  S.  350. 
*  Centralbl.  f .  d.  med.  Wissensch. ,  1878,  No.  20. 


2 

3 

0.273 

0.254 

4.272 

4.351 

3.611 

3.717 

0.136 

0.126 

0.038 

0.045 

0.011 

0.011 

128  THE  BLOOD. 

II.  The  Forni-elenients  of  the  BloocL 

The  Red  Blood-corpuscles, 

The  blood-corpuscles  are  round,  biconcave  disks  without  mem- 
brane and  nucleus  in  man  and  mammalia  (with  the  exception  of  the 
llama,  the  camel,  and  their  congeners).  In  the  latter  animals,  as 
also  in  birds,  amphibia,  and  fishes  (with  the  exception  of  the 
cyclostoma),  the  corpuscles  have  in  general  a  nucleus,  are  biconvex 
and  more  or  less  elliptical.  The  size  varies  in  different  animals. 
In  man  they  have  an  average  diameter  of  7  to  8  /^  (yu  =  0.001 
mm.)  and  a  maximum  thickness  of  1.9yU.  The  volume  of  a  single 
red  corpuscle  of  a  horse  amounts  to  0.00000003858  c.mm.  and  of 
a  pig  0.0000000435  c.mm.  (Wendelstadt  and  L.  Bleibtreu'). 
The  weight  of  a  red  corpuscle  of  a  horse  is,  according  to  the  same 
investigators,  0.00000004307  mg.  Their  specific  gravity  is  1.088 
to  1.105.  They  are  heavier  than  the  blood-plasma  or  serum,  and 
therefore  sink  in  these  liquids.  In  the  discharged  blood  they  may 
lie  sometimes  with  their  flat  surfaces  together,  forming  a  cylinder 
like  a  roll  of  coin.  The  reason  for  this  is  unknown,  but  as  it  may 
be  observed  in  defibrinated  blood  it  seems  probable  that  the  forma- 
tion of  fibrin  has  nothing  to  do  with  it.  Seen  with  the  microscope, 
each  blood-corpuscle  has  a  pale  yellow  color,  and  only  in  moderately 
thick  layers  is  the  color  somewhat  reddish. 

The  number  of  red  blood-corpuscles  is  different  in  the  blood  of 
various  animals.  In  the  blood  of  man  there  are  generally  5  million 
red  corpuscles  in  1  c.mm.,  and  in  woman  4  to  4.5  million. 

On  diluting  the  blood  with  water  and  alternately  freezing  and 
thawing  it,  as  also  on  shaking  it  with  ether,  or  by  the  action  of 
chloroform  or  bile,  a  remarkable  change  takes  place.  The  blood- 
coloring  matters,  which  are  hardly  free  in  the  blood-corpuscles,  but 
rather,  according  to  the  view  of  Hoppe-Seyler,  are  combined  with 
some  other  substance,  perhaps  lecithin,  are  by  this  means  set  free 
from  these  combinations  and  pass  into  solution,  while  the  remainder 
of  each  blood-corpuscle  forms  a  swollen  mass.  By  the  action  of 
carbon  dioxide,  by  the  careful  addition  of  acids,  acid  salts,  tincture 
of  iodine,  or  certain  other  bodies,  this  residue,  rich  in  albumin, 
condenses  and  in  many  cases  the  form  of  the  blood-corpuscles  may 

'  Pfliiger's  Arcliiv,  Bd.  52. 


STROMA.  129 

"be  again  obtained.  This  residue  has  been  called  the  stroma  of  the 
red  blood-corpuscles. 

To  isolate  the  stromata  of  the  blood-corpnscles  they  are  washed 
first  by  diluting  the  blood  with  10-20  vols,  of  a  1-lfo  common-salt 
solution  and  then  separating  the  mixture  by  centrifugal  force  or  by 
allowing  it  to  stand  at  a  low  temperature.  This  is  repeated  a  few 
times  until  the  blood-corpuscles  are  freed  from  serum.  These 
purified  blood-corpuscles  are,  according  to  Wooldridge,  mixed 
with  5-6  vols,  of  water  and  then  a  little  ether  is  added  until  com- 
plete solution  is  obtained.  The  leucocytes  gradually  settle  to  the 
bottom,  a  movement  which  may  be  accelerated  by  centrifugal  force, 
and  the  liquid  which  separates  therefrom  is  very  carefully  treated 
with  a  1^  solution  of  KHSO,  until  it  is  about  as  dense  as  the 
original  blood.  The  separated  stromata  are  collected  on  a  filter 
and  quickly  washed. 

Wooldridge  '  found  as  constituents  of  the  stroma  lecithin, 
choleste7'in,  7iucleoalbumi7i,  and  a  glohulm  which,  according  to 
Halliburton,  is  probably  a  nucleoproteid  which  he  calls  cell- 
glohulm.  No  nuclein  substances  or  seralbumin  or  albumoses  could 
be  detected  by  Halliburtojt  and  Friend.'  The  nucleated  red 
blood-corpuscles  of  the  bird  contain,  according  to  Plosz  and 
Hoppe-Seyler,^  nuclein  and  an  albuminous  body  which  swells  to  a 
slimy  mass  in  a  10^  common-salt  solution,  and  which  seems  to  be 
closely  related  to  the  hyaline  substance  {hyaline  substance  of 
Rovida)  occurring  in  the  lymph-cells.  The  red  blood-corpuscles 
without  any  nucleus  are,  as  a  rule,  very  poor  in  proteid  but  are  rich 
in  haemoglobin ;  the  nucleated  corpuscles  are  richer  in  proteid  and 
poorer  in  haemoglobin. 

A  gelatinous,  fibrin-like  proteid  body  may  be  obtained  from  the 
red  blood-corpuscles  under  certain  circumstances.  This  fibrin-like 
mass  has  been  observed  on  freezing  and  then  thawing  the  sediment 
of  the  blood-corpuscles,  or  on  discharging  the  spark  from  a  large 
Leyden  Jar  through  the  blood,  or  on  dissolving  the  blood-corpuscles 
of  one  kind  of  animal  in  the  serum  of  another  (Landois,  stroma- 
Jibrin*).  In  none  of  these  cases  has  it  been  shown  that  we  have  to 
deal  with  a  fibrin  formation  at  the  expense  of  the  stroma.    It  seems 

'  Du  B  )is-Reymond'3  Arcliiv,  1881,  S.  387. 

«  Journal  of  Physiol.,  Vol.  10. 

'  Hoppe-Seyler's  Med.  chem.  Untersucli.,  S.  510. 

■•Centralbl.  f.  d.  med.  Wissenscli.,  1874,  S.  421. 


130  TEE  BLOOD. 

only  to  have  been  shown  that  the  red  blood-corpuscles  of  frog's 
blood  contain  fibrinogen  (Alex.  Schmidt  and  Semmer'). 

The  mineral  bodies  of  the  red  corpuscles  are  chiefly  potassium, 
phosphoric  acid,  and  chlorine;  in  the  red  corpuscles  of  man,  the 
dog,  and  the  ox  sodium  has  also  been  found. 

The  most  important  constituent  of  the  blood -corpuscles  from  a 
physiological  standpoint  is  the  red  coloring  matter. 

Blood-coloring  Matters. 

According  to  Hoppe-Setler^  the  coloring  matter  of  the  red 
blood-corpuscles  is  not  in  a  free  state,  but  combined  with  some  otner 
substance.  The  crystalline  coloring  matter,  the  hsemoglobin  or 
oxyhaemoglobin,  which  may  be  isolated  from  the  blood,  is  con- 
sidered, according  to  Hoppe-Seyler,  as  a  cleavage  product  of  this 
combination,  and  it  acts  in  many  ways  unlike  the  questionable  com- 
bination itself.  This  combination  is  insoluble  in  water  and  uncrys- 
tallizable.  It  strongly  decomposes  hydrogen  peroxide  without  being 
oxidized  itself;  it  shows  a  greater  resistance  to  certain  «chemical 
reagents  (as  potassium  ferricyanide)  than  the  free  coloring  matter, 
and  lastly  it  gives  off  its  loosely  combined  oxygen  much  more  easily 
in  vacuum  than  the  free  pigment.  To  distinguish  between  the 
cleavage  products,  the  haemoglobin  and  the  oxyhaemoglobin, 
Hoppe-Seyler  '  calls  the  combination  of  the  blood-coloring  matter 
of  the  venous  blood-corpuscles  plileMn^  and  that  of  the  arterial 
arterin.  Since  the  above-mentioned  combination  of  the  blood- 
coloring  matters  with  other  bodies,  for  example  (if  they  really  do 
exist)  with  lecithin,  have  not  been  closely  studied,  the  following 
statements  will  only  apply  to  the  free  pigment,  the  haemoglobin. 

The  color  of  the  blood  depends  in  part  on  hcBmogloim  or  jjseudo- 
hcemoglohin  (see  below),  and  in  part  on  a  molecular  combination  of 
this  with  oxygen,  the  oxyhcBmoglolin.  We  find  in  blood  after 
asphyxiation  almost  exclusively  hsemoglobin  and  pseudo-hsemo- 
globin,  in  arterial  blood  disproportionately  large  amounts  of  oxy- 
haemoglobin, and  in  venous  blood  a  mixture  of  both.  Blood-color- 
ing matters  are  found  also  in  striated  as  well  as  in  certain  smooth 
muscles,  and  lastly  in  solution  in  different  invertebrates.  The 
■quantity  of  haemoglobin  in  human  blood  may  indeed  be  somewhat 

'  Alex.  Schmidt  in  Pflliger's  Arcluv,  Bd.  11,  S.  550-559. 
*  Zeitschr.  f.  physioL  Chem.,  Bd.  13. 
2  Ihid.,  S.  495. 


COMPOSITION  OF  H^iJMOGLOBIN. 


131 


variable  under  different  circumstances,  bnt  amounts  averaging 
about  l-^fo  or  8.5  grammes  have  been  determined  for  each  kilo  of 
the  weight  of  the  body. 

Haemoglobin  belongs  to  the  group  of  compound  proteids,  and 
yields  as  cleavage  products,  besides  very  small  amounts  of  volatile 
fatty  acids  and  other  bodies,  chiefly  proteid  (96^)  and  a  coloring 
matter,  limmochromogen  (-t/^),  containing  iron,  which  in  the  pres- 
ence of  oxygen  is  easily  oxidized  into  luematin. 

Tlie  hemoglobin  prepared  from  different  kinds  of  blood  has 
not  exactly  the  same  composition,  which  seems  to  indicate  the 
presence  of  different  hemoglobins.  The  analyses  of  different 
investigators  of  the  hgemoglobin  from  the  same  kind  of  blood  do 
not  always  agree  with  one  another,  which  jjrobably  depends  upon 
the  somewhat  various  methods  of  preparation.  The  following 
analyses  are  given  as  examples  of  the  constitution  of  different 
hgemogrlobins : 


Haemoglobin    ^ 

from  the 
Dog 53.85 

"    54.57 

Horse  ....  54.87 

"     5115 

Ox 54.66 

Pig 54  17 

"  54.71 

Guinea-pig  54  12 
Squirrel  . .   54  09 

Goose 54. 26 

Hen 52.47 


H 

7.32 
7.22 
6.97 

6  76 
7.25 
7.38 

7  38 
7.36 
7.39 
7.10 
7.19 


N 

16.17 
16.38 
17.31 
17.94 
17.70 
16.23 
17.43 
16,78 
16.09 
16.21 
16.45 


S 

0.390 
0.568 
0.650 
0.390 
0.447 
0.660 
0.479 
0.580 
0.400 
0.540 
0.857 


Fe        0 


P.O5 


0.430  21  84  (Hoppe-Seyler>) 

0.336  20.93  (Jaquet"^) 

0.470  19.73  (KossEL^) 

0.335  23.43  (Zinopfsky^) 

0.400  19.543  (HdfnerS) 

0.430  21.360  (Otto«) 

0.399  19  602  (Hufner) 

0.480  20.680  (Hoppe-Seyler) 

0.590  21.440  

0.430  20.690  0.77 

0.335  22. 500  0.197  ( J  aquet) 


The  question  whether  the  amount  of  phosphorus  in  the  haemo- 
globin from  birds  exists  as  a  contamination  or  as  a  constituent  has 
not  been  decided.  According  to  Inoko'  the  haemoglobin  from 
goose's  blood  consists  of  a  combination  between  nucleic  acid  and 
haemoglobin.  In  the  hasmoglobin  from  the  horse  (Zixoffskt), 
the  pig,  and  the  ox  (Hufnek)  we  have  1  atom  of  iron  to  2  atoms 
of  sulphur,  while  in  the  haemoglobin  from  the  dog  (Jaquet)  the 
relation  is  1  to  3.     From  the  data  of  the  elementary  analysis,  as 

'  Med.  chem.  Untersuch. ,  S.  370. 

»  Zeitschr.  f.  pbysiol.  Chem.,  Bd.  14,  S.  296. 

^  Ihid.,  Bd.  2,  S.  150. 

■•  Ihid..  Bd.  10. 

»  Beitr.  z.  Physiol.,  Festschr.  f.  C.  Ludwig,  1887,  S.  74-81. 

•  Zeitschr.  f.  physiol.  Chem.,  Bd.  7,  S.  61. 

•I  Ihid.,  Bd.  18. 


132  THE  BLOOD. 

also  from  the  amount  of  loosely  combined  oxygen,  Hufnek  '  has 
calcalated  the  molecular  weight  of  dog-hgemoglobin  as  14,129  and 
the  formula  C^jHj^^^Nj^^FeSgOjgj.  The  molecular  weight  is  there- 
fore very  high.  The  haemoglobin  from  various  kinds  of  blood  not 
only  shows  a  diverse  constitution,  but  also  a  different  solubility  and 
crystalline  form,  and  a  varying  quantity  of  water  of  crystallization; 
hence  we  infer  that  there  are  several  kinds  of  haemoglobin. 

BoHR°  is  a  very  zealous  advocate  of  this  supposition.  He  has 
been  able  to  obtain  hgemoglobin  from  dog  and  horse  blood,  by 
fractional  crystallization,  which  had  different  power  of  combining 
with  oxygen  and  containing  different  quantities  of  iron.  Hoppe- 
Seylee^  had  already  prepared  two  different  forms  of  haemoglobin 
crystals  from  hoTse's  blood,  and  Bohr  concludes  from  a  collection 
of  these  observations  that  the  ordinary  hgemoglobin  consists  of  a 
mixture  of  different  hsemoglobins.  In  opposition  to  this  state- 
ment HuEifEE*  has  shown  that  only  one  haemoglobin  exists  in  ox 
blood,  and  that  this  is  probably  true  for  the  blood  of  many  other 
animals. 

Oxy haemoglobin,  which  has  also  been  called  h^matoglobulix 
or  H^MATOCRTSTALLiN,  is  a  molecular  combination  of  hsemoglobin 
and  oxygen.  For  each  molecule  of  haemoglobin  1  molecule  of 
oxygen  exists;  and  the  amount  of  loosely  combined  oxygen  which 
is  united  to  1  grm.  haemoglobin  (of  the  dog)  has  been  determined 
by  Hufner'  as  1.34  c.c.  (calculated  at  0°  0.  and  760  mm.  mer- 
cury). 

According  to  Bohk^  the  facts  are  different.  He  differentiates  between  four 
different  oxyhsemogiobins,  according  to  the  quantity  of  oxygen  which  they 
absorb,  namely,  a-,  f3-,  y-,  and  ^-oxyhsemoglobin,  all  having  the  same  absorp- 
tion-spectrum and  1  gm.  combining  with  respectively  0"4,  0'8,  1*7,  and  2'7  cc. 
oxygen  at  the  temperature  of  the  room  and  with  an  oxygen  pressure  of  150  mm. 
mercury.  The  T^-oxyhsemoglobin  is  the  ordinary  one  obtained  by  the  customary 
method  of  preparation.  Bohr  designates  as  a-oxyhsemoglobin  the  crystalline 
powder  obtained  by  drying  ;K-oxyh3emoglobin  in  the  air.  On  dissolving 
or-oxyhaemoglobin  in  water  it  is  converted  into  yS-oxyhaemoglobin  without 
decomposition,  and  the  quantity  of  iron  is  increased.    On  keeping  a  solution  of 

Journ.  f.  prakt.  Chem.,  Bd.  33. 

"^  "Sur  les  combinaisons  de  Themoglobine  avec  I'oxygene."  Extrait  du 
Bulletin  de  I'Academie  Royale  Danoise  des  sciences,  1890  ;  also  Centralbl.  f . 
Physiol.,  1890,  S.  249. 

^  Zeitschr.  f.  physiol.  Chem. ,  Bd.  8. 

^  Du  Bois-Reymond's  Archiv,  1894. 


OXYHEMOGLOBIN.  133 

T'-oxyliEBmoglobin  in  a  sealed  tube  it  is  transformed  into  ^-oxybsemoglobiu, 
iiltliough  tbe  circumstances  of  tbis  cbange  are  not  known.  According-  to 
Hiifner '  tbese  are  notbing  but  a  mixture  of  genuine  and  partly  decomposed 
bi3emoglobins. 

The  ability  of  liEemoglobin  to  take  np  oxygen  seems  to  be  a 
function  of  the  iron  it  contains,  and  when  this  is  calculated  as 
about  0.33-0.40/'^,  then  1  atom  of  iron  in  the  haemoglobin  corre- 
sponds to  about  2  atoms  =  1  molecule  of  oxygen.  The  combination 
of  hfemoglobin  with  oxygen  is,  as  has  been  stated,  loose  and  dis- 
sociatable,  and  the  quantity  of  oxygen  taken  up  by  a  ha3moglobin 
solution  depends  upon  the  pressure  of  the  oxygen  at  that  tempera- 
ture. If  this  latter  be  decreased  by  means  of  a  vacuum,  especially 
on  gently  heating  or  by  passing  some  indifferent  gas  through  the 
solution,  all  of  the  oxygen  may  be  expelled  from  an  oxyhsemoglobin 
solution  so  that  only  ha?moglobin  remains.  The  reverse  of  this  is 
true  of  a  hasmoglobin  solution  which  by  its  remarkable  attraction 
for  oxygen  may  be  converted  into  oxyhaemoglobin.  Oxyhemoglobin 
is  generally  considered  as  a  weak  acid. 

Oxyhaemoglobin  has  been  obtained  in  crystals  from  several 
varieties  of  blood.  These  crystals  are  blood-red,  transparent,  silky, 
and  may  be  2-3  mm.  long.  The  oxyhfemoglobin  from  squirrel's 
blood  crystallizes  in  six-sided  plates  of  the  hexagonal  system;  the 
other  varieties  of  blood  yield  needles,  prisms,  tetrahedra,  or  plates 
which  belong  to  the  rhombic  system.  The  quantity  of  water  of 
cr3^stallization  varies  between  3-10^  for  the  different  oxyhaemo- 
globins.  When  completely  dried  at  a  low  temperature  over  sul- 
phuric acid  the  crystals  may  be  heated  to  110-115°  C.  without 
decomposing.  At  higher  temperatures,  somewhat  above  1G0°  C, 
they  decompose,  giving  an  odor  of  burnt  horn,  and  leave,  after 
complete  combustion,  an  ash  consisting  of  oxide  of  iron.  The 
oxyhremoglobin  crystals  from  difficultly  crystallizable  kinds  of 
blood,  for  example  from  such  as  ox's,  human,  and  pig's  blood,  are 
easily  soluble  in  water.  The  oxyhemoglobin  from  easily  crystal- 
lizable blood,  as  from  that  of  the  horse,  dog,  squirrel,  and  guinea- 
pig,  are  soluble  with  difficulty  in  the  order  above  given.  The 
oxyhemoglobin  dissolves  more  easily  in  a  very  dilute  solution  of 
alkali  carbonate  than  in  pure  water,  and  this  solution  may  be  kept. 
The  presence  of  a  little  too  much  alkali  causes  the  oxyhaemoglobin 
to  quickly  decompose.     The  crystals  are  insoluble  without  decolor- 

'  Du  Bois-Reymond's  Archiv,  1894. 


134  THE  BLOOD. 

ization  in  absolute  alcohol.  According  to  Nencki,'  it  is  hereby- 
converted  into  an  isomeric  or  polymeric  modification,  called  by  him 
parahmmoglohm.  Oxyhemoglobin  is  insoluble  in  ether,  chloroform, 
benzol,  and  carbon  disnlphide. 

A  solution  of  oxyhsemoglobin  in  water  is  precipitated  by  many 
metallic  salts,  but  is  not  precipitated  by  sugar  of  lead  or  basic  lead 
acetate.  On  heating  the  watery  solution  it  decomposes  at  60°  to 
70°  C,  and  it  splits  off  proteid  and  hsematin.  It  is  also  decom- 
posed by  acids,  alkalies,  and  many  metallic  salts.  It  gives  the 
ordinary  reactions  for  proteids  with  the  ordinary  proteid  reagents 
which  first  decompose  the  oxyhaemoglobin  with  the  splitting  off  of 
proteid. 

The  oxyhaemoglobin  may,  when  it  is  gradually  oxidized,  act  as 
an  "  ozone  exciter  "  by  the  decomposition  of  neutral  oxygen,  con- 
verting it  into  active  oxygen  (Pflugee,  '') .  It  may  also  have  another 
relation  to  ozone,  since  it  has  the  property  of  an  "  ozone  trans- 
mitter" in  that  it  causes  the  reaction  of  certain  reagents  (turpen- 
tine) containing  ozone  upon  ozone  reagents  such  as  tincture  of 
guaiacuHv 

A  sufficiently  dilate  solution  of  oxyhaemoglobin  or  arterial  blood 
shows  a  spectrum  with  two  absorption-bands  between  the  Fraun- 
HOFER  lines  D  and  E.  The  one  band,  a^  which  is  narrower  but 
darker  and  sharper,  lies  on  the  line  D;  the  other,  broader,  less 
defined  and  less  dark  band,  ft,  lies  at  E.  These  bands  can  be 
detected  in  a  layer  of  1  cm.  thick  of  a  0.1  p.  m.  solution  of 
oxyhsemoglobin.  In  a  still  weaker  dilation  the  band  ft  first  dis- 
appears. By  increased  concentration  of  the  solution  the  two  bands 
become  broader,  the  space  between  them  smaller  or  entirely  obliter- 
ated, and  at  the  same  time  the  blue  and  violet  part  of  the  spectrum 
IS  darkened.  The  oxyhsemoglobin  may  be  differentiated  from  other 
coloring  matters  having  a  similar  absorption-spectrum  by  its 
behavior  towards  reducing  substances.     (See  below.) 

A  great  many  methods  have  been  proposed  for  the  preparation 
of  oxyhsemoglobin  crystals,  but  in  their  chief  features  they  all  agree 
with  the  following  method  as  suggested  by  Hoppe-Seyler  ' :  The 
washed  blood-corpnscles  (best  those  from  the  dog  or  the  horse)  are 
stirred   with  2  vols,    water  and   then   shaken   with  ether.     After 

'  Nenchi  and  Sieber,  Ber.  d.  deutsch.  cliem.  Gesellsch.,  Bd.  18. 
«  Pfluger's  Arcliiv,  Bd.  10,  S.  252. 
3  Med.  chem.  Untersuch.,  S.  181. 


HMMOGLOBIN.  135 

decanting  the  ether  and  allowing  the  ether  which  is  retained  by  the 
blood  solution  to  evaporate  in  an  open  dish  in  the  air,  cool  the 
filtered  blood  solution  to  0°  C,  add  while  stirring  \  vol.  of  alcohol 
also  cooled,  and  allow  to  stand  a  few  days  at  —  5°  to  —  10°  C. 
The  crystals  which  separate  may  be  repeatedly  recrystallized  by 
dissolving  in  water  of  about  35°  C,  cooling  and  adding  cooled 
alcohol  as  above.  Lastly,  they  are  washed  with  cooled  water  con- 
taining alcohol  {\  vol.  alcohol)  and  dried  in  vacnnni  at  0°  C.  or  a 
lower  temperature.  According  to  Gscheidlex's  '  investigations, 
oxyhgemoglobin  crystals  may  be  obtained  from  difficultly  crystalliz- 
able  varieties  of  blood  by  allowing  the  blood  first  to  putrefy  slightly 
in  sealed  tubes.  After  shaking  with  air  by  which  the  blood  is  again 
arterialized,  proceed  as  above. 

For  the  preparation  of  oxyhaemoglobin  crystals  in  small  quanti- 
ties from  blood  easily  crystallized,  it  is  often  sufficient  to  stir  a  droi> 
of  blood  with  a  little  water  on  a  microscope  slide  and  allow  the 
mixture  to  evaporate  so  that  the  drop  is  surrounded  by  a  dried  ring. 
After  covering  with  a  thin  glass,  the  crystals  gradually  appear 
radiating  from  the  ring.  These  crystals  are  formed  in  a  surer 
manner  if  the  blood  is  first  mixed  with  some  water  in  a  test-tube 
and  shaken  with  ether  and  a  drop  of  the  lower  deep-colored  liquid 
treated  as  above  on  the  slide. 

Haemoglobin,  also  called  reduced  hemoglobin  or  purple 
CRUORIN  (Stokes'),  occurs  only  in  very  small  quantities  in  arterial 
blood,  in  larger  quantities  in  venous  blood,  and  is  nearly  the  only 
blood -coloring  matter  after  asphyxiation. 

Haemoglobin  is  much  more  soluble  than  the  oxyhaemoglobin, 
and  it  can  therefore  only  be  obtained  as  crystals  with  difficulty. 
These  crystals  are  as  a  rule  isomorphons  to  the  corresponding 
oxyhaemoglobin  crystals,  but  are  darker,  having  a  shade  towards 
blue  or  purple,  and  are  decidedly  more  pleochromatic.  Its  solu- 
tions in  water  are  darker  and  more  violet  or  purplish  than  solutions 
of  oxyhaemoglobm  of  the  same  concentration.  They  absorb  the 
blue  and  the  violet  rays  of  the  sj^ectrum  m  a  less  marked  degree, 
but  strongly  absorb  the  rays  lying  between  C  and  D.  In  proper 
dilation  the  solution  shows  a  spectrum  with  one  broad,  not  sharply 
defined  band  between  D  and  E.  This  band  does  not  lie  in  the 
middle  between  D  and  E,  but  is  towards  the  red  end  of  the 
spectrum,  a  little  over  the  line  D.  A  haemoglobin  solution  actively 
absorbs  oxygen  from  the  air  and  is  converted  into  an  oxyhaemo- 
globin solution. 

'  Pfliiger's  Archiv,  Bd   16. 

*  Philosophical  Magazine,  Vol.  28,  No.  190,  Nov.  1864. 


136  THE  BLOOD. 

A  solution  of  oxyhaemoglobin  may  be.  easily  con-verted  into  a 
solution  having  the  spectrum  of  hsemoglobin  by  means  of  a  vacuum, 
by  passing  an  indifferent  gas  through  it,  or  by  the  addition  of  a 
reducing  substance,  as,  for  example,  an  ammoniacal  ferro- tartar te 
solution  (Stokes'  reduction-liquid).  If  an  oxyhemoglobin  solution 
or  arterial  blood  is  kept  in  a  sealed  tube,  we  observe  a  gradual 
consumption  of  oxygen  and  a  reduction  of  the  oxyhaemoglobin  into 
hsemoglobin.  If  the  solution  has  a  proper  concentration,  a  crystal- 
lization of  hsemoglobin  may  occur  in  the  tube  at  lower  temperatures 
(Hufner'). 

Pseudohaemoglobin.  Ludwig  and  Siegfeied''  have  observed 
that  blood  which  has  been  reduced  by  hyposulphites  so  completely 
that  the  oxyhemoglobin  spectrum  disappears  and  only  the  hemo- 
globin spectrum  is  seen  yields  large  amounts  of  oxygen  when 
exposed  to  a  vacuum.  Blood  which  has  been  reduced  by  the 
passage  of  a  stream  of  hydrogen  through  it  until  the  oxyhemo- 
globin spectrum  disappears  acts  in  the  same  manner.  Hence  a 
loose  combination  of  hemoglobin  and  oxygen  exists  which  gives 
the  hemoglobin  spectrum,  and  this  combination  is  called  pseudo- 
liemoglobin  by  Lijdwig  and  Siegfried.  Pseudohemoglobin, 
whose  presence  has  been  detected  in  asphyxiation  blood  from  dogs, 
is  considered  by  the  author  as  an  intermediate  step  between 
hemoglobin  and  oxyhemoglobin,  on  the  reduction  of  the  latter. 

Methsemoglobin.  This  name  has  been  given  to  a  coloring 
matter  which  is  easily  obtained  from  oxyhemoglobin  as  a  trans- 
formation product  and  which  has  been  correspondingly  found  in 
transudations  and  cystic  fluids  containing  blood,  in  urine,  in 
hematuria  or  hemoglobinuria,  also  in  urine  and  blood  on  poisoning 
with  potassium  chlorate,  amy]  nitrite  or  alkali  nitrite,  and  many 
other  bodies. 

Methemoglobin  does  not  contain  any  oxygen  in  molecular  or 
dissociable  combination,  but  still  the  oxygen  seems  to  be  of  impor- 
tance in  the  formation  of  methemoglobin,  because  it  is  formed  from 
oxyhemoglobin  in  the  absence  of  oxygen  or  oxidizing  agents,  and 
not  from  hemoglobin.  If  arterial  blood  be  sealed  up  in  a  tube, 
it  gradually  consumes  its  oxygen  and  becomes  venous,  and  by  this 
absorption  of  oxygen  a  little  methemoglobin  is  formed.  The  same 
occurs  on  the  addition  of  a  small  quantity  of  acid  to  the  blood. 

»  Zeitschr.  f.  physiol.  Chem,    Bd.  4,  S.  382. 

'  Du  Bois-Reymond's  ArcMv,  1890 ;  also  see  Ivo  Novi,  Pfliiger's  Archiv, 
Bd.  56. 


METH^  miO  GLOBIN.  137 

By  the  spontaneous  decomjiosition  of  blood  some  methaemoglobin 
is  formed,  and  by  the  action  of  ozone,  jiotassium  permanganate, 
jjotassinm  ferricyanide,  chlorates,  nitrites,  nitrobenzol,  pyrogallol, 
pyrocatechin,  acetanilid,  and  certain  other  bodies  on  the  blood  an 
abundant  formation  of  metliEemoglobin  takes  place. 

According  to  the  investigations  of  Hufner,  Kulz,  and  Otto  ' 
methremoglobin  contains  just  as  mucli  oxygen  as  oxyhasmoglobin, 
but  it  is  more  strongly  combined.  Jaderholm  ■'  and  Saarbach  ^ 
claim  that  a  methsemoglobin  solution  is  first  converted  into  an 
oxyhemoglobin  and  then  into  a  haemoglobin  solution  by  reducing 
substances,  while  Hoppe-Seyler  and  Araki  *  claim  that  it  is  con- 
verted directly  into  a  haemoglobin  solution. 

Methsemoglobin  has  the  same  constitution  as  oxyha3moglobin 
(HtlFNER  and  Otto).  It  was  first  shown  by  them  that  it  crystal- 
lizes in  brownish-red  needles,  prisms,  or  six-sided  plates.  It  dis- 
solves easily  in  water;  the  solution  has  a  brown  color  and  becomes 
a  beautiful  red  on  the  addition  of  alkali.  The  solution  of  the  pure 
substance  is  not  precipitated  by  basic  lead  acetate  alone,  but  by 
basic  lead  acetate  and  ammonia.  The  absorption-spectrum  of  a 
watery  or  acidified  solution  of  methaemoglobin  is,  according  to 
Jaderholm  atid  Bertin-Sans,^  very  similar  to  that  of  hsematin  in 
acid  solution,  but  is  easily  distinguished  from  the  latter  since,  on 
the  addition  of  a  little  alkali  and  a  reducing  substance,  the  former 
passes  over  to  the  spectrum  of  reduced  haemoglobin,  while  a 
hsematin  solution  under  the  same  conditions  gives  the  spectrum  of 
an  alkaline  hajmocliromogen  solution  (see  below).  Methaemoglobin 
in  alkaline  solution  shows  two  absorption-bands  which  are  like  the 
two  oxyhaemoglobin  bands,  but  they  differ  from  these  in  that  the 
band  ^  is  stronger  than  a.  By  the  side  of  the  band  a  and  united 
with  it  by  a  shadow  lies  a  third,  fainter  band  between  C  and  D^ 
near  to  D.  According  to  other  investigators,  Araki  and  Dit- 
TRiCH,^  a  neutral  or  faintly  acid  methsemoglobin  solution  shows 
only  one  characteristic  band  a  between  C  and  D,  and  the  second 

'  Zeitschr.  f.  physiol.  Cliem. ,  Bd.  7. 

'  Nord.  med,  Arkiv,  Bd   16,  and  Zeitschr.  f.  Biologie,  Bd.  16. 
»  Pfliiger's  Arcliiv,  Bd.  28. 
*  Zeitschr.  f   physiol.  Chem.,  Bd.  14. 
^  Compt.  rend  ,  Tome  106. 

■*  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  29.     Important  references  on  methae- 
moglobin are  given  by  Otto,  Pfliiger's  Archiv,  Bd.  31. 


138  THE  BLOOD. 

band   between   D    and   E  is    only   due    to    contamination   with 
oxyhaemoglobiu. 

Crystallized  methgenioglobin  may  be  easily  obtained  by  treating 
a  concentrated  solution  of  oxyhsemoglobin  with  a  sufficient  quantity 
of  concentrated  potassium  ferricyanide  solution  to  give  the  mixture 
a  porter-brown  color.  After  cooling  to  0°  C.  add  i  vol.  cooled 
alcohol  and  allow  the  mixture  to  stand  a  few  days  in  the  cold.  The 
crystals  may  be  easily  purified  by  recrystallizing  from  water  by  the 
addition  of  alcohol. 

Carbon  Monoxide  Haemoglobin '  is  the  molecular  combination 
between  1  mol.  haemoglobin  and  1  mol.  CO.  This  combination  is 
stronger  than  the  oxygen  combination  of  haemoglobin.  The  oxygen 
is  for  this  reason  easily  driven  off  by  carbon  monoxide,  and  this 
explains  the  poisonous  action  of  carbon  monoxide,  which  kills  by 
the  expulsion  of  the  oxygen  of  the  blood.  Hufnek'  has  deter- 
mined the  dissociation  constant  of  carbon-monoxide  haemoglobin 
and  finds  it  equal  to  0.074  for  a  solution  containing  on  an  average 
11  gm.  in  100  c.c.  at  a  temperature  of  32.7°  C.  The  dissociation 
constant  of  carbon  monoxide  haemoglobin  is  hence  abont  33  times 
smaller  than  that  of  oxyhemoglobin  under  nearly  the  same  condi- 
tions (^for  oxyhaemoglobiu  =  2.44). 

Carbon  monoxide  haemoglobin  is  formed  by  saturating  blood  or 
a  hsemoglobin  solution  with  carbon  monoxide,  and  maybe  obtained 
as  crystals  by  the  same  means  as  oxyhaemoglobin.  These  crystals 
are  isomorphous  to  the  oxyhaBmoglobin  crystals,  but  are  less  soluble 
and  more  stable,  and  their  bluish-red  color  is  more  marked.  For 
the  detection  of  carbon-monoxide  haemoglobin  its  absorption  spec- 
trum is  of  the  greatest  importance.  This  spectrum  shows  two 
bands  which  are  very  similar  to  those  of  oxyhaemoglobin,  but  they 
occur  more  towards  the  violet  part  of  the  spectrum.  These  bands 
do  not  change  noticeably  on  the  addition  of  reducing  substances; 
this  constitutes  an  important  difference  between  carbon  monoxide 
and  oxyhaemoglobin.  If  the  blood  contains  oxyhaemoglobin  and 
carbon-monoxide  haemoglobin  at  the  same  time,  we  obtain  on  the 
addition  of  a  reducing  substance  (ammoniacal  ferrotartrate  solution) 
a  mixed  spectrum  originating  from  the  haemoglobin  and  carbon- 
monoxide  haemoglobin. 

'  In  reference  to  carbon  monoxide  lisemoglobin  see  especially  Hoppe-Seyler, 
Med.  cliem.  Untersuch.,  S.  201;  Centralbl.  f.  d.  med.  Wissenscli.,  1864  and  1865; 
Zeitschr.  f.  pbysiol.  Cham.,  Bdd.  1  and  13. 

^  Du  Bois-Reymond's  Archiv,  Physiol.  Abtb.,  1895. 


CARBON  DIOXIDE  HAEMOGLOBIN.  139 

A  great  many  reactions  have  been  suggested  for  the  detection  of 
carbon-monoxide  ha?nioglobin  in  medico-legal  cases.  A  simple  and 
at  the  same  time  a  good  one  is  Hoppe-Setler's  soda  test.  The 
blood  is  treated  with  double  its  volume  of  caustic-soda  solution  of 
1.3  sp.  gr.,  by  which  ordinary  blood  is  converted  into  a  dingy 
brownish  mass,  which  when  spread  out  on  jjorcelain  is  brown  with 
a  shade  of  green.  Carbon-monoxide  blood  gives  under  the  same 
conditions  a  red  mass,  which  if  spread  out  on  porcelain  shows  a 
beautiful  red  color.  Several  modifications  of  this  test  have  been 
proposed. 

Carbon  monoxide  methaemogloMn  has  been  prepared  by  Weil  and  v.  Akrep  ' 

by  the  action  of  potassium  permanganate  on  carbon  monoxide  lisenioglobia,  but 
this  is  contradicted  by  Bertix-Saxs  and  Moitessier.-  Sulphur  methaBmogiobin 
is  the  name  given  by  Hoppe-Seyler  ^  to  that  coloring  matter  which  is  formed 
by  the  action  of  sulphuretted  hydrogen  on  oxyhaemoglobin.  The  solution  has 
a  greenish-red,  dirty  color  and  shows  an  absorption-baud  in  the  red.  This 
coloring  matter  is  claimed  to  be  the  greenish  color  seen  on  the  surface  of  putre- 
fying flesh. 

Carbon-dioxide  HaBmoglobin,   CarlohmmogloUn.     Haemoglobin, 

according  to  Bohr'  and  Torup,^  also  forms  a  molecular  combina- 
tion with  carbon  dioxide  whose  spectrum  is  similar  to  that  of 
haemoglobin.  According  to  Bohr  there  are  three  different  carbo- 
haemoglobins,  namely,  a-,  /?-,  and  ;K-carboha3moglobin,  in  which 
1  gm.  combines  with  respectively  l.o,  '>,  and  G  c.c.  CO^  (measured 
at  0°  C.  and  760  mm.)  at  +  18°  C  and  a  pressure  of  GO  mm. 
mercury.  If  a  hremoglobin  solution  is  shaken  with  a  mixture  of 
oxygen  and  carbon  dioxide,  the  hifiuioglobin  combines  loosely  with 
the  oxygen  as  well  as  carbon  dioxide,  independently  of  each  other, 
just  as  if  each  gas  existed  alone  (Bohr).  He  considers  that  the 
two  gases  are  combmed  with  different  parts  of  the  haemoglobin, 
namely,  the  oxygen  with  the  pigment  nucleus  and  the  carbon  dioxide 
with  the  proteid  component.  According  to  Torup  the  hajmoglobin 
must  therefore  be  partly  decomposed  by  the  carbon  dioxide  setting 
free  some  proteid. 

'  Du  Bois-Reymond's  Archiv,  1880. 

-  Compt.  rend.,  Tome  113. 

3  Med.  chem.  Untersuch.,  S.  151;  also  see  Araki,  Zeitschr.  f.  physiol.  Chem., 
Bd.  14. 

■•  "Etudes  sur  les  combinaisons  du  sang  avec  I'acide  carbonique.'  Estrait 
du  Bull,  de  I'Acad.  Danoise,  1890,  also  Centralbl,  f.  Physiol.,  Bd.  4,  1890. 

^  Maly's  Jahresber. ,  Bd.  17,  S.  115. 


140  THE  BLOOD. 

Nitric-oxide  Haemoglobin '  is  also  a  crystalline  molecular  com- 
bination which  is  even  stronger  than  the  carbon-monoxide  haemo- 
globin. Its  solution  shows  two  absorption-bands  which  are  paler 
and  less  sharp  than  the  carbon-monoxide  haemoglobin  bands,  and 
the}''  do  not  disappear  on  the  addition  of  redacing  bodies. 

Hsemoglobin  also  forms  a  molecular  combination  witli  acetylene.  Methse- 
moglobin  solutions  become  of  a  beautiful  red  color  by  the  action  of  hydrocyanic 
acid,  and,  according  to  Robert,^  cyanmethcemoglohin  is  probably  formed.  Its 
spectrum  is  very  similar  to  that  of  hsemoglobin,  but  it  is  not  converted  into 
oxyhsemoglobin  on  shaking  with  air. 

Decomposition  products  of  the  blood-coloring  matters.  By  its 
decomposition  hsemoglobin  yields,  as  above  stated,  a  proteid,  which 
has  been  called  glohm,  and  a  ferraginoas  j9?^?;zm^  as  chief  products. 
If  the  decomposition  takes  j)lace  in  the  absence  of  oxygen,  a  color- 
ing matter  is  obtained  which  is  called  by  Hoppe-Setler  hcemo- 
cliromogen,  by  other  investigators  (Stokes)  reduced  hcematm.  In 
the  j)resence  of  oxygen,  h^mochromogen  is  quickly  oxidized  to 
haematin,  and  we  therefore  obtain  in  this  case  hcematin  as  a  colored 
decomposition  product.  As  hsemochromogen  is  easily  converted  by 
oxygen  into  hsematin,  so  this  latter  may  be  reconverted  into  hsemo- 
chromogen  by  reducing  substances. 

Hsemochromogen  was  discovered  by  Hoppe-Setler.'  He  has 
also  been  able  to  obtain  this  coloring  matter  as  crystals.  Haemo- 
chromogen  is,  according  to  Hoppe-Setler,  the  colored  atomic 
groaj)  of  haemoglobin  and  its  combination  with  gases,  and  this 
atomic  group  is  combined  with  proteids  in  the  coloring  matter. 
The  characteristic  absorption  of  light  depends  on  the  haemochromo- 
gen,  and  it  is  also  this  atomic  group  which  binds  in  the  oxyhsemo- 
globin 1  mol.  oxygen  and  in  the  carbon-monoxide  hemoglobin 
1  mol.  carbon  monoxide  with  1  atom  iron.  Hoppe-Seyler  has 
observed  a  combination  between  haemochromogen  and  carbon  mon- 
oxide, and  this  combination  shows  the  spectral  appearance  of  carbon 
monoxide  hsemoglobin. 

An  alkaline  haemochromogen  solution  has  a  beautiful  red  color. 
It  shows  two  absorption-bands,  first  described  by  Stokes,  of  which 
the  one  is  darker  and  lies  between  D  and  E,  and  the  other,  broader 

'  See  Herrmann  and  Reichert  in  Du  Bois-Keymond's  Archiv,  1865,  and 
Hoppe-Seyler,  Med.  chem.  Untersuch.,  S.  204. 

'  Ueber  Cyanmethtemoglobin  und  den  Nachweis  der  Blausaure.  Stutt- 
gart, 1891. 

8  Zeitschr.  f.  physiol.  Chem.,  Bd.  12. 


H.iJ MATIN.  141 

but  not  so  dark,  covers  the  lines  E  and  h.  In  acid  solution  hgemo- 
chroniogen  shows  four  bands,  which,  according  to  Jaderholm,' 
depend  on  a  mixture  of  haemochromogen  and  haematoporphy/iii 
(see  below),  this  last  formed  by  a  partial  decomposition  resulting 
from  the  action  of  the  acid. 

Haemochromogen  may  be  obtained  as  crystals  by  the  action  of 
caustic  soda  on  hasmoglobin  at  100°  C.  in  the  absence  of  oxygen 
(Hoppe-Setler),  By  the  decomposition  of  haemoglobin  by  acids 
(of  course  in  the  absence  of  air)  we  obtain  haemochromogen  con- 
taminated with  a  little  h^matoporphyrin.  An  alkaline  haemo- 
chromogen solution  is  easily  obtained  by  the  action  of  a  reducing 
substance  (Stokes'  reduction  liquid)  on  an  alkaline  haematin  solu- 
tion. 

Haematin,  also  called  Oxyhsematin,  is  sometimes  found  in  old 
transudations.  It  is  formed  by  the  action  of  gastric  or  pancreatic 
juices  on  oxyhaemoglobin,  and  is  therefore  also  found  in  the  faeces 
after  hemorrhage  in  the  intestinal  canal,  and  also  after  a  meat  diet 
and  food  rich  in  blood.  It  is  stated  that  hsematin  may  occur  in 
urine  after  poisoning  with  arseniuretted  hydrogen.  As  shown 
above,  the  haematin  is  formed  by  the  decomposition  of  oxyhaemo- 
globin, or  at  least  of  hsemoglobin,  in  the  presence  of  oxygen. 
Bertin-Saxs  and  Moitessier"  have  prepared  an  intermediate 
body  between  oxyhaemoglobin  and  hsmochromogen.  This  reduced 
haematin  shows  one  band  whose  middle  lies  over  D. 

The  constitution  of  haematin  may,  according  to  Hoppe-Sey- 
LER,'  be  exj)ressed  by  the  formula  Cj^Hg^N^FeO^.  According  to 
Nencki  and  Sieber  it  has  the  formula  C3,H35N,FeO^,  and  they 
claim  that  haematin  is  a  hydrate  of  a  body  not  yet  isolated,  haemin, 
C3.H3„X,Fe03. 

Haematin  is  amorphous,  dark  brown  or  bluish  black.  It  may 
be  heated  to  180°  C.  without  decomposition;  on  burning  it  leaves 
a  residue  consisting  of  iron  oxide.  It  is  insoluble  in  water,  dilute 
acids,  alcohol,  ether,  and  chloroform,  but  it  dissolves  slightly  in 
warm  glacial  acetic  acid.  H^matin  dissolves  in  acidified  alcohol  or 
ether.  It  easily  dissolves  in  alkalies,  even  when  very  dilute.  The 
alkaline  solutions  are  dichroitic ;  in  thick  layers  they  appear  red  by 
transmitted  light,  and  in  thin  layers  greenish.     The  alkaline  sola- 

'  Nord.  med.  Arkiv,  Bd.  16. 

'  Compt.  rend.,  Tome  116. 

*  Med.  cheni.  Untersuch.,  S.  525. 


14:2  THE  BLOOD. 

tions  are  precipitated  by  lime-  and  baryta-water,  as  also  by  solutions 
of  neutral  salts  of  the  alkaline  earths.  The  acid  solutions  are 
always  brown. 

An  acid  haematin  solution  absorbs  the  red  part  of  the  spectrum 
less  and  the  violet  part  more.  The  solution  shows  a  rather  sharply 
defined  band  between  Cand  D  whose  position  may  change  with  the 
variety  of  acid  used  as  a  solvent.  Between  D  and  F  a  second,  much 
broader,  less  sharply  defined  band  occurs  which  by  proper  dilution 
of  the  liquid  is  converted  into  two  bands.  The  one  between  h  and 
i^,  lying  near  F^  is  darker  and  broader,  the  other,  between  D  and 
^,  lying  near  E,  is  lighter  and  narrower.  Also  by  proper  dilution 
a  fourth  very  faint  band  is  observed  between  D  and  E  lying  near  D. 
Haematin  may  thus  in  acid  solution  show  four  absorption-bands; 
ordinarily  one  sees  distinctly  only  the  bands  between  (7  and  D  and 
the  broad,  dark  band — or  the  two  bands — between  D  and  F.  In 
alkaline  solution  the  hsematin  shows  a  broad  absorption-band,  which 
lies  in  greatest  part  between  G  and  Z),  but  reaches  a  little  over  the 
line  D  towards  the  right  in  the  space  between  D  and  E. 

Hsemin,  H^Miisr  Crystals,  or  Teichmanist's  Crystals.  Hae- 
min,  according  to  Hoppe-Seyler,  is  a  combination  between  hae- 
matin and  hydrochloric  acid,  having  the  formula  C3^H3gN^FeOj.HCl. 
Nei^cki  and  Sieber  designate  as  haemin,  on  the  contrary  (see  page 
141),  a  body  not  yet  isolated,  of  the  formula  C^^H^^IST^FeOj,  which 
may  be  considered  as  an  anhydride  of  haematin  or  Cj^Hj^N^FeO^ 
—  HjO.  The  haemin  crystals  are,  according  to  the  latest  views,  a 
combination  of  this  substance,  haemin,  and  HCl,  according  to  the 
formula  Cj^Hg^N^FeOj.HCl.  The  analyses  of  the  hydrochloride  and 
hydrobromide  of  haematin  by  Hup^ster  and  Kuster  '  lead  to  the 
same  formula. 

According  to  Nencki  and  Sieber  the  haemin  crystals  are  a  double  combina- 
tion with  the  solvent,  amyl  alcohol  or  acetic  acid,  which  is  used  in  their 
preparation;  while  Hoppe-Seyler  claims  that  the  solvent  is  only  held  mechani- 
cally by  the  crystals.  The  formula  of  the  haemin  crystals  prepared  by  means 
of  amyl  alcohol  is,  according  to  Nencki  and  Sieber, 

(C3,H3oN4Fe03.HC])4.C5Hi,0. 

Haemin  crystals  form  in  large  masses  a  bluish-black  powder,  but 
are  so  small  that  they  can  only  be  seen  by  the  microscope.  They 
consist  of  dark -brown  or  nearly  brownish-black,  long,  rhombic,  or 
spool-like  crystals,  isolated,  or  grouped  as  crosses,  rosettes,  or  starry 

>  Ber.  d.  deutsch.  chem.  Gesellsch,,  Bd.  37,  S.  572. 


R^EMIN.  148 

forms.  They  are  insoluble  in  water,  dilute  acids  at  the  norinul 
temperature,  alcohol,  ether,  and  chloroform.  They  are  slightly 
dissolved  by  glacial  acetic  acid  and  warmth.  They  dissolve  in 
acidified  alcohol,  as  also  in  dilute  caustic  or  carbonated  alkalies; 
and  in  the  last  case  they  form,  besides  alkali  chlorides,  soluble 
haematin  alkali,  from  which  the  hsematin  may  be  precipitated  by  an 
acid.  , 

The  preparation  of  lismin  crystals  is  always  the  starting-point 
for  the  preparation  of  hamatin.  According  to  Hofpe-Seyler,' 
shake  the  blood-corpuscles  which  have  been  washed  with  common- 
salt  solution  with  water  and  ether,  then  filter  the  solution 
of  blood-coloring  matters,  concentrate  strongly,  mix  with  10-20 
vols,  glacial  acetic  acid,  and  heat  for  1-3  hours  on  the  water- 
bath.  After  diluting  with  several  volumes  of  water,  allow  the 
liquid  to  stand  a  few  days.  The  crystals  which  separate  are  then 
washed  with  water,  boiled  with  acetic  acid,  and  then  washed  again 
with  water,  alcohol,  and  ether.  Ne^tcki  and  Siebek  coagulate  the 
sediment  of  the  blood-corpuscles  by  alkali,  allow  the  coagulum  to 
dry  incompletely  in  the  air,  rub  it  fine,  and  then  boil  it  with  amyl 
alcohol  after  the  addition  of  a  little  hydrochloric  acid.  The  crystals 
which  separate  from  the  filtrate  after  cooling  are  washed  with 
water,  alcohol,  and  ether.  If  hasmin  crystals  be  dissolved  in  dilute 
caustic  alkali,  hajmatin  may  be  precipitated  from  the  solution  by 
the  addition  of  acid;  and  from  this  hajmatin  pure  haemin  crystals 
may  be  prepared  by  heating  with  glacial  acetic  acid  and  a  little 
common  salt. 

In  preparing  haemin  crystals  in  small  amounts  proceed  in  the 
following  manner:  The  blood  is  dried  after  the  addition  of  a  small 
quantity  of  common  salt,  or  the  dried  blood  may  be  rubbed  with  a 
trace  of  common  salt.  The  dry  powder  is  placed  on  a  microscope- 
slide,  moistened  with  glacial  acetic  acid,  and  then  covered  with  the 
cover-glass.  Add,  by  means  of  a  glass  rod,  more  glacial  acetic  acid 
by  applying  the  drop  at  the  edge  of  the  cover-glass,  until  the  space 
between  the  slide  and  the  cover-glass  is  full.  Now  warm  over  a 
very  small  flame,  with  the  precaution  that  the  acetic  acid  does  not 
boil  and  pass  with  the  powder  from  under  the  cover-glass.  If  no 
crystals  appear  after  the  first  warming  and  cooling,  warm  again, 
and  if  necessary  add  some  more  acetic  acid.  After  cooling,  if  the 
experiment  has  been  properly  performed,  a  number  of  dark-brown 
or  nearly  black  hgemin  crystals  of  varying  forms  will  be  seen. 

Hasmatin  is  dissolved  by  concentrated  sulphuric  acid  in  the 
presence  of  air,  forming  a  purple-red  liquid.  The  iron  is  here  split 
off  and  the  new  coloring  matter,  called  hcBmatoporphyrin  by  Hoppe- 

-  Med.  chern.  Uutersuch.,  S.  379. 


144  THE  BLOOD. 

Seyler/  is  iron-free.  The  litematin  yields  "witli  concentrated  sul- 
phuric acid,  in  the  absence  of  air,  a  second  iron-free  coloring  matter 
called  limmatolin  (Hoppe-Setler).  Hgematoporphyrin  may  also 
be  prepared  by  the  action  of  glacial  acetic  acid  saturated  with 
hydrobromic  acid  on  h^min  crystals  (KEiSrcKi  and  Sieber^). 

Hsematoporphyrin,  0^^11,5^203.  This  pigment,  accordiug  to 
Mac  MuiiTisr,^  occurs  as  a  physiological  coloring  matter  in  certain 
animals.  It  has  been  repeatedly  observed  in  the  last  few  years  in 
human  urine  especially  after  the  use  of  sulphonal  (see  Chapter  XV 
on  the  urine).  This  coloring  matter  is,  according  to  Nexcki  and 
SiEBER,  an  isomer  of  the  bile-pigment  bilirubin,  and  its  formation 
from  h^ematin  can  be  expressed  by  the  following  equation: 

C3A,N,0,Fe  +  2H,0  -  Fe  =  2C„H,,N,03. 

A  pigment  closely  allied  to  the  urinary  pigment  urobilin  has  been 
obtained  by  the  action  of  reducing  substances  on  h^motoporphyrin 
(Hoppe-Sbyler,"  Neistcki  and  Sieber,'  Le  Nobel,"  Mac  Munn"  '). 
On  the  administration  of  haemotoporphyrin  to  rabbits,  Nen^cki  and 
RoTSCHY  *  observed  that  a  part  was  reduced  to  a  substance  similar 
to  urobilin. 

The  combinations  of  haemotoporphyrin  with  Na  and  with  HCl 
have  been  obtained  as  crystals  by  Nei^cki  and  Sieber.  The  acid 
alcoholic  solutions  have  a  beautiful  purple  color,  which  becomes 
violet-blue  on  the  addition  of  large  quantities  of  acid.  The  alkaline 
solution  has  a  beautiful  red  color,  especially  when  not  too  much 
alkali  is  j)resent.  Hsematoporphyrin  prepared  by  various  methods 
may  differ  somewhat  in  solubility  and  in  color  of  solution,  but  their 
characteristic  absorption-spectra  are  essentially  the  same. 

An  alcoholic  solution  of  hsematoporphyrin,  acidulated  with 
hydrochloric  or  sulphuric  acid,  shows  two  absorption-bands,  of 
which  one  is  fainter  and  narrower  and  lies  between  C  and  Z>, 
near  D.     The  other  is  much  darker,  sharper  and  broader  and  lies 

'  Med.  cbem.  Untersucli. ,  S.  528. 
^  Monatsliefte  f.  Chem.,  Bd.  9. 
'  Journ.  of  Physiol.,  Vol.  7. 

*  Med.  chem.  Untersuch.,  S.  533. 
5  Monatshef te  f .  Chem. ,  Bd.  9. 

*  Pflliger's  Archiv,  Bd.  40. 

■'  Proc.  Roy.  Soc,  1880,  No.  208  ;  Journ.  of  Physiol.,  Vol.  10. 
8  Monatshefte  f.  Chem.,  Bd.  10. 


H^MATOIDIN.  145 

in  the  middle  between  D  and  E.  An  absorption  extends  from 
these  bands  towards  the  red,  terminating  with  a  dark  edge,  which 
may  be  considered  as  a  third  band  between  the  other  two. 

A  dilute  alkali  solution  shows  four  bands,  namely,  a  band 
between  C  and  D;  a  second,  broader,  surrounding  D  and  with  its 
broadest  part  between  D  and  E\  a  third,  between  D  and  E  nearly 
at  E\  and  lastly  a  fourth,  broad  and  dark  band  between  h  and  F. 
On  the  addition  of  an  alkaline  zinc-chloride  solution  the  spectrum 
changes  more  or  less  rapidly,'  and  finally  a  spectrum  is  obtained 
with  only  two  bands,  of  which  one  surrounds  D  and  the  other  lies 
between  D  and  E. 

Haematoidin,  thus  called  by  Vikchow,  is  a  coloring  matter 
which  crystallizes  in  orange-colored  rhombic  plates,  and  which 
occurs  in  old  blood  extravasations,  and  whose  origin  from  the  blood- 
coloring  matters  seems  to  be  established  (Langhans,  Cordua, 
QuixcKE,  and  others '').  A  solution  of  haematoidin  shows  no 
absorption-bands,  but  only  a  strong  absorption  of  the  violet  to  the 
green  (Ewald').  According  to  most  observers,  haematoidin  is 
identical  with  the  bile-coloring  matter  bilirubin.  It  is  not  identical 
with  the  crystallizable  lutein  from  the  corpora  lutea  of  the  ovaries 
of  the  cow  (Piccolo  and  Liebex,'  Kuhxe  and  Ewald). 

In  the  detection  of  the  above-described  blood-coloring  matters 
the  spectroscope  is  the  only  entirely  trustworthy  means  of  investi- 
gation. If  it  is  only  necessary  to  detect  blood  in  general  and  not 
to  determine  definitely  whether  the  coloring  matter  is  haemoglobin, 
methfemoglobm,  or  haematin,  then  the  preparation  of  haemin  crys- 
tals is  an  absolute  positive  proof.  The  reader  is  referred  to  more 
extended  text-bopks  for  exacter  methods  for  the  detection  of  blood 
in  chemico-legal  cases,  and  it  is  perhaps  sufficient  to  give  here  the 
chief  points  of  the  investigation. 

If  spots  on  clothes,  linen,  wood,  etc.,  are  to  be  tested  for  the 
presence  of  blood,  it  is  best,  when  possible,  to  scratch  or  shave  off 
as  much  as  possible,  rub  with  common  salt,  and  from  this  prepare 
the  hasmin  crystals.  On  obtaining  positive  results  the  presence  of 
blood  is  not  to  be  doubted.  If  you  do  not  obtain  sufficient  material 
by  the  above  means,  then  soak  the  spot  with  a  few  drops  of  water 
in  a  watch-crystal.     If  a  colored  solution  is  thus  obtained,   then 

'  Hammarsten,  Skan.  Arch.  f.  Physiol.,  Bd.  3. 

'  A  comprehensive  review  of  the  literature  pertaining  to  haematoidin  may  be 
found  in  Stadelmann.  Der  Icterus,  etc.     Stuttgart,  1891.     Pages  3  and  45. 
3  Zeitschr.  f.  Biologie,  Bd.  22,  S.  475. 
*  Cit.  from  Gorup-Besanez:  Lehrbuch  d.  physiol.  Chem.,  4.  Aufl.,  1878. 


146  THE  BLOOD. 

remove  the  fibres,  wood-shavings,  and  the  like  as  far  as  possible, 
and  allow  the  solution  to  dry  in  the  watch-glass.  The  dried  residue 
may  be  partly  used  for  the  spectroscope  test  dii'ectly,  and  part  may 
be  employed  in  the  preparation  of  the  h^min  crystals.  It  also 
serves  to  detect  haemochromogen  in  alkaline  solution  after  previous 
treatment  with  alkali  and  the  addition  of  reducing  substances. 

If  a  colorless  solution  is  obtained  after  soaking  with  water,  or 
the  spots  are  on  rusty  iron,  then  digest  with  a  little  dilute  alkali 
(5  p.  m.).  In  the  presence  of  blood  the  solution  gives,  after 
neutralization  with  hydrochloric  acid  and  drying,  a  residue  which 
may  give  the  hsemin  crystals  with  glacial  acetic  acid.  Another  part 
of  the  alkaline  solution  shows,  after  the  addition  of  Stokes'  redac- 
tion liquid,  the  absorption-bands  of  hamochromogen  in  alkaline 
jsolution. 

The  methods  proposed  for  the  quantitative  estimation  of  the 
blood -coloring  matters  are  partly  chemical  and  partly  physical. 

Among  the  chemical  raethods  to  be  mentioned  is  the  ashing  of  the  blood 
and  the  determinaton  of  the  amount  of  iron  contained  therein,  from  which  the 
amount  of  haemoglobin  may  be  calculated.  Another  method  consists  in  first 
saturating  the  blood  completely  with  oxygen.  Now  pump  out  thoroughly  this 
«xygen,  and  calculate  from  the  amount  of  oxygen  the  amount  of  haemoglobin 
present  ((jKehant  '  and  Quinquaud-).     None  of  these  methods  is  reliable. 

The  physical  methods  consist  either  in  a  colorimetric  or  a  spec- 
troscopic investigation. 

The  principle  of  Hoppe-Setler's  colorimetric  method  is  that  a 
measured  quantity  of  blood  is  diluted  with  an  exactly  measured 
quantity  of  water  until  the  dilated  blood  solution  has  the  same  color 
as  a  pare  oxyhgemoglobin  solution  of  a  known  strength.  The 
amount  of  coloring  matter  present  in  the  undiluted  blood  may  be 
easily  calculated  from  the  degree  of  dilution.  In  the  colorimetric 
testing  we  use  a  glass  vessel  with  parallel  sides  containing  a  layer 
of  liquid  1  cm.  thick  (hgematinometer  of  Hoppe-Seyler).  The 
method  is  good,  and  the  inconvenience  that  the  normal  solution  of 
oxyhaemoglobin  does  not  keep  for  any  length  of  time  without 
decomposing  may  be  prevented  by  preserving  the  solution  in  sealed 
tubes.  The  oxyhaemoglobin  is  gradually  reduced  to  a  hsemoglobin 
solution  which  may  be  kept  for  years,  and  when  required  for  use  it 
•fis  converted  into  an  oxyhaemoglobin  solution  by  aerating,  x^ccord- 
"ng  to  an  improved  method  by  Hoppe  Seyler,^  it  is  much  better  to 
ase  a  solution  of  carbon-monoxide  hemoglobin,  as  normal  solution. 
The  blood  solution  in  this  case  is  saturated  with  carbon  monoxide 

'  Compt.  rend. ,  Tome  75. 
•^  Ibid.,  Tome  76. 

3  Zeitschr.  f.  physiol.  Chem.,  Bd.  16,  and  Lehrbuch  d.  physiol.  u.  pathol. 
chem.  Analyse,  6.  Aufl.,  1893, 


SPECTROPllOTOMETRIC  ESTIMATIOX.  147 

aud  the  two  solutions  compared  in  a  specially  constructed  colori- 
metric  double  pipette  (see  original  article).  The  replacing  of  the 
oxyhcemoglobin  solution  by  a  solution  of  picrocarmin,  as  suggested 
by  certain  investigators,  is  to  be  rejected  according  to  Hoppe- 
Seyler. 

The  quantitative  estimation  of  the  blood -coloring  matters  by 
means  of  the  spectroscope  may  be  done  in  different  ways,  but  at  the 
present  time  the  spectropliotometnc  method  is  chiefly  used,  and  this 
seems  to  be  the  most  reliable.  This  method  '  is  based  on  the  fact 
that  the  extinction  coefficient  of  a  colored  liquid  for  a  certain  region 
of  the  spectrum  is  directly  proportional  to  the  concentration,  so  that 
C  :  E  =  C\  :  E^,  when  C  and  C^  represent  the  different  concentra- 
tions and  E  and  E^   the  corresponding  coefficient  of  extinction. 

C       C 
From  the  equation  ^  =  -=f  it  follows  that  for  one  and  the  same 

£j         E  ^ 

coloring  matter  this  relation,  which  is  called  the  absorption  ratio^ 
must  be  constant.  If  the  absorption  ratio  is  represented  by  A,  the 
determined  extinction  coefficient  by  E,  and  the  concentration  (the 
amount  of  coloring  matter  in  grams  in  1  c.c.)  by  (7,  then  0  =  A  .  E. 
Different  apparatus  have  been  constructed  (Vierordt  and 
HuFXER°)  for  the  determination  of  the  extinction  coefficient  which 
is  equal  to  the  negative  logarithm  of  those  rays  of  light  which 
remain  after  the  passage  of  the  light  through  a  layer  1  cm.  thick  of 
an  absorbing  liquid.  In  regard  to  these  apparatus  the  reader  is 
referred  to  other  text-books. 

As  control  the  extinction  coefficients  are  determined  in  two  different  regions 
of  the  spectrum,  namely,  D'd-iE^DHE  and  I)QoE—D84E  The  constants 
or  the  absorption  ratio  for  these  two  regions  of  the  spectrum  are  designated  by 
HuFNER  by  A  and  A'.  Before  the  determination  the  blood  must  be  diluted 
with  water,  and  if  the  proportion  of  dilution  of  the  blood  be  represented  by  V, 
then  the  concentration  or  the  amount  of  coloring  matter  in  100  parts  of  the 
undiluted  blood  is 

C=  100.  F.  A  .  E  and 

C  =  100  .  V.  A'    E\ 

The  absorption  ratio  or  the  constants  in  the  two  above-mentioned  regions 
of  the  spectrum  have  been  determined  for  oxyhaemoglobin,  haemoglobin,  carbon- 
monoxide  hfemoglobin,  and  methsemoglobin. 

The  figures  for  the  above  coloring  matters  obtained  from  canine  blood  are 
as  follows  : 

Oxyhaemoglobin Ao  =  0.001330   and   A' „  =  0.001000 

Haemoglobin Jl,.  =  0.001091     "      ^'r  =  0.001351 

Carbon  monoxide  haemoglobin  Ac  =  0.001130     "      ^-1'^  =  O.OOlOOO 
Methaemoglobin .   A,n=  0.003696     "      ^'„.=  0.002798 

The  quantity  of  each  coloring  matter  may  be  determined  in  a  mixture  of 
two  blood-coloring  matters  by  this  method,  which  is  of  special  importance  in 

'  See  Vierordt,  Die  Anwendung  des  Spektralapparates  zu  Photometrie,  etc. 
(Tilbingeu,  1873),  and  Hiifner,  Zeitschr.  f.  physiol.  Chem.,  Bd.  3;  v.  NoorJen, 
lUd.,  Bd.  4;  Otto,  lUd.,  Bd.  7 ;  and  Pfluger's  Archiv,  Bdd.  31  and  36. 

•'  L.  c. 


14:8  TEE  BLOOD. 

the  determination  of  the  quantity  of  osyhsemoglobin  and  haemoglobin  present 
in  blood  at  the  same  time.  If  we  represent  by  E  and  E'  the  extinction  coeffi- 
cients of  the  mixture  in  the  above-mentioned  regions  of  the  spectrum,  by^o  and 
A o  and  Ar  and  A' r  the  constants  for  oxyhgemoglobin  and  reduced  haemoglobin, 
and  by  Fthe  degree  of  dilution  of  the  blood,  then  the  percentage  of  osyhsemo- 
globin Ho  and  of  (reduced)  haemoglobin  llr  is 

^.  =  100.  F.^"^'^^^^—^'^'^^ 


^  o^r  —  -Ao^  f 


and 


A  oAr  —  AqA  r 

Among  the  many  apparatus  constructed  for  clinical  purposes  for 
the  quantitative  estimation  of  haemoglobin  the  hsemometer  of 
Fleischl  '  is  to  be  preferred.  The  determination  by  this  a^^paratus 
is  made  by  comparing  the  color  of  the  blood  diluted  with  water  with 
the  color  of  a  wedge-shaijed  movable  prism  of  red  glass.  If  the 
blood  shows  the  same  color  as  the  glass  prism,  then  the  amount  of 
haemoglobin  in  the  blood  may  be  directly  read  from  the  scale.  The 
amount  of  haemoglobin  is  expressed  as  percentage  of  the  physiologi- 
cal amount  of  haemoglobin. 

Many  other  coloring  matters  are  found  besides  the  often-occurring  haemo- 
globin in  the  blood  of  invertebra.  In  a  few  arachnidae,  Crustacea,  gasteropodse, 
and  cephalopodae  a  body  analogous  to  haemoglobin  containing  copper,  hmmo- 
cyanin,  has  been  found  by  Feedericq.^  By  the  taking  up  of  loosely  bound 
oxygen  this  body  is  converted  into  blue  oxyfuBmocyanin,  and  by  the  escape  of 
the  oxygen  becomes  colorless  again.  A  coloring  matter  called  chlorocruorin  by 
Lankestee*  is  found  in  certain  chaetopodse.  Hmmerythrin  ,*  so  called  by  Kku- 
KENBERG  but  first  observed  by  Schwalbe,  is  a  red  coloring  matter  from  certain 
gephyrea.  Besides  haemocyanin  we  find  in  the  blood  of  certain  Crustacea  the 
red  coloring  matter  tetronerythrin  (Hallibueton^),  which  is  also  widely 
spread  in  the  animal  kingdom.  Echinochrom,  so  named  by  Mac  Munn,^  is  a 
brown  coloring  matter  occurring  in  the  perivisceral  fluid  of  a  variety  of  echino- 
derms. 

The  quantitative  constitution  of  the  red  Hood-corpuscles  is  diffi- 
cult to  determine,  and  we  have  hardly  any  sufficiently  trustworthy 
analyses  of  them.  The  amount  of  water  varies  in  different  varieties 
of  blood  between  570-G30  p.  m.,  with  a  corresponding  amount, 
430-370  p.  m.,  of  solids.  The  chief  mass,  about  •=^,  of  the  dried 
substance  consists  of  hsemoglobin  (in  human  and  canine  blood). 

^  See  V.  Jaksch,  Klinische  Diagnostik,  4.  Aufl.,  p.  18. 

5  Extrait  des  Bulletins  de  I'Acad.  Roy.  de  Belgique  (2),  Tome  46,  1878. 

3  Journ.  of  Anat.  and  Physiol.,  1868,  p.  114,  and  1870,  p.  119. 

4  See  Physiol.  Studien,  Reihe  1,  Abth.  3.     Heidelberg,  1880. 
^  Journal  of  Physiol.,  Vol.  6. 

«  Quart.  Journ.  Microsc.  Science,  1885. 


LEUCOCYTES.  149 

According  to  the  analyses  of  Hoppe-Setler  '  and  his  pupils, 
the  red  corpuscles  contain  in  1000  parts  of  the  dried  substance: 


Haemoglobin. 

Albumin. 

Lecithin. 

Cholesterin, 

Human  blood . . 

.     868-943 

123-51 

7.2-3.5 

2.5 

Dog           "     .. 

..       865 

126 

5.9 

8.6 

Goose        "     .. 

..       627 

364 

4.6 

4.8 

Snake        "     . . 

..       467 

525 

Of  special  interest  is  the  varying  proportion  of  the  hajmoglobin 
to  the  proteid  in  the  nucleated  and  in  the  non-nucleated  blood- 
corpuscles.  These  last  are  much  richer  in  haemoglobin  and  poorer 
in  proteid  than  the  others. 

According  to  M.  and  L.  Bleibtreu  and  Wendelstadt  *  the 
amount  of  nitrogen  in  the  red  corpuscles  seems  to  be  constant  in 
certain  animals,  such  as  the  horse  and  the  pig.  The  quantity  of 
proteid  (inclusive  of  haemoglobin)  in  the  moist  corpuscles  of  the 
horse  was  468.5  and  in  the  pig  4-43.6  p.  m.  as  calculated  by  the 
above  experiments  from  the  quantity  of  nitrogen. 

The  amount  of  mineral  bodies,  as  far  as  they  have  been  deter- 
mined, in  the  moist  corpuscles  is  4.8-8.9  p.  m.  The  chief  mass 
consists  of  potassium,  phosphoric  acid,  and  chlorine.  The  blood- 
corpuscles  of  ox-blood  contain,  according  to  Bunge,  more  sodium 
and  chlorine  than  phosphoric  acid  and  potassium.  The  blood- 
corpuscles  of  the  pig  and  horse  contain  no  sodium  (Bunge  ^). 
Human-blood  corpuscles  contain,  according  to  Wanach,"  about  five 
times  as  much  potassium  as  sodium,  on  an  average  3.99  p.  m. 
potassium  and  0.75  p.  m.  sodium. 


The  White  Blood-corpuscles  and  the  Blood-plates. 

The  White  Blood-corpuscles,  also  called  Leucocytes  or 
Lymphoid  Cells,  which  occur  in  the  blood  in  varying  forms  and 
sizes,  form  in  a  state  of  rest  spherical  lumps  of  a  sticky,  highly 
refractive  power,  capable  of  motion,  non-membranous  protoplasm, 
which  show  1-4  nuclei  on  the  addition  of  water  or  acetic  acid.  In 
human  and  mammalian  blood  they  are  larger  than  the  red  blood- 
-corpuscles.     They  have  also  a  lower  specific  gravity  than  the  red 

>  Med.  chem.  Untersucli.,  S.  390  and  393. 
»  Pfluger's  Archiv,  Bdd.  51  and  52. 
3  Zeitschr.  f.  Biologie,  Bd.  12,  S.  206,  207. 
<  Maly's  Jahresber.,  Bd.  18,  S.  88. 


150  THE  BLOOB. 

corpuscles,  move  in  the  circulating  blood  nearer  to  the  walls  of  the 
vessel,  and  have  also  a  slower  motion. 

The  number  of  white  blood-corpuscles  varies  not  only  in  the 
different  blood-vessels,  but  also  under  different  physiological  condi- 
tions. As  an  average  we  have  only  1  white  corpuscle  for  350-500 
red  corpuscles.  According  to  the  investigations  of  Alex.  Schmidt  ^ 
and  his  pupils,  the  leucocytes  are  destroyed  in  great  part  on  the 
discharge  of  the  blood  before  and  during  coagulation,  so  that  dis- 
charged blood  is  much  poorer  in  leucocytes  than  the  circulating 
blood.  The  correctness  of  this  statement  has  been  denied  by  other 
investigators. 

From  a  histological  standpoint  we  generally  discriminate  between 
the  different  kinds  of  colorless  blood-corpuscles;  chemically  consid- 
ered, however,  there  is  no  known  essential  difference  between  them. 
With  regard  to  their  importance  in  the  coagulation  of  fibrin  Alex. 
Schmidt  and  his  pupils  distinguish  between  the  leucocytes  which 
are  destroyed  by  the  coagulation  and  those  which  are  not.  The 
last  mentioned  give  with  alkalies  or  common-salt  solutions  a  slimy 
mass;  the  first  do  not  show  such  behavior. 

The  protoplasm  of  the  leucocytes  has  during  life  amoeboid 
movements  which  partly  make  possible  the  wandering  of  the  cells 
and  partly  the  taking  up  of  smaller  grains  or  foreign  bodies  within 
the  same.  On  these  grounds  the  occurrence  of  myosin  \u.  them  has 
been  admitted  even  without  any  special  proof  thereof.  Alex. 
Schmidt  '^  claims  to  have  found  serglohulin  in  equine-blood  leuco- 
cytes which  had  been  washed  with  ice-cold  water.  There  are  also 
certain  leucocytes  as  above  stated  which  yield  a  slimy  mass  when 
treated  with  alkalies  or  NaCl  solutions,  which  seem  to  be  identical 
with  the  so-called  hyaline  suhstance  of  Kovida  found  in  the  pus- 
cells.  On  digesting  the  leucocytes  with  water  a  solution  of  a 
proteid  body  is  obtained  which  can  be  precipitated  by  acetic  acid 
and  which  is  not  soluble  in  an  excess  of  the  acid  and  forms  the 
chief  mass  of  the  leucocytes.  This  substance,  which  is  undoubt- 
edly related  to  coagulation,  has  been  described  under  different 
names  (see  Chapter  V),  and  consists,  chiefly  at  least,  of  nucleo- 
histon. 

Glycogen  has  been  found  in  the  leucocytes  by  Hoppe-Setler,' 

'  Pfliiger's  Archiv,  Bd.  11. 
«L.c. 

3  Physiol.  Chem.     Berlin,  1878-1881.     S.  83. 


BLOOD-PLA  TES.  1  5 1 

Salomon,'  Gabritschewsky,'  and  other  investigators.  The 
glycogen  found  by  Huppert,'  Czerny,'  and  others  in  the  blood 
probably  originated  from  the  leucocytes.  The  constituents  of  the 
leucocytes  are  the  same  as  the  constituents  of  the  cell  as  described 
in  Chapter  V. 

The  blood-plates  (Bizzozero's),  haematoblasts  (Hayem),  whose 
nature  and  physiological  importance  have  been  much  questioned, 
are  pale,  colorless,  gummy  disks,  round  or  more  oval  in  shape  and 
generally  with  a  diameter  two  or  three  times  smaller  than  the  red 
blood-corpnscles.  Certain  investigators  claim  that  the  blood-plates 
occur  preformed  in  the  circulating  blood,  while  others  on  the  con- 
trary deny  this.  According  to  Lowit  "  the  blood-plates  are  formed 
from  the  leucocytes  with  the  elimination  of  globulin  substance, 
hence  they  are  also  called  globulin-plates.  According  to  Mosen 
these  globulin-plates  are  not  identical  with  the  true  blood-plates, 
and  these  first  are  derived  very  likely  from  the  latter.  The  blood- 
plates  separate  into  two  substances  by  the  action  of  diffei-ent 
reagents,  namely,  one  which  is  homogeneous  and  non-refractive, 
while  the  other  is  highly  refractive  and  granular.  Blood-plates 
readily  stick  together  and  attach  themselves  to  foreign  bodies. 

According  to  the  important  researches  of  Kossel  and  Lilien"- 
FELD  °  the  blood-plates  coasist  of  a  chemical  combination  between 
proteid  and  nuclein,  and  hence  they  are  called  nuclein-plates  by 
LiLiEXFELD.  According  to  this  investigator  they  are  derivatives 
of  the  cell  nucleus,  a  view  which  is  in  accord  with  Hlava's  state- 
ments. It  seems  certain  that  the  blood-plates  stand  in  a  certain 
relationship  to  the  coagulation  of  blood,  and  according  to  Lilien- 
FELD  the  fibrin  coagulation  is  indeed  a  function  of  the  cell  nucleus. 
The  importance  of  these  formations  to  blood  coagulation  will  be 
referred  to  later. 

'  Deutsch.  med.  Wochenscbr.,  1877.  Nos.  8  and  35. 

«  Arch.  f.  exp.  Path,  und  Pharm..  Bd.  38. 

»Centralbl.  f.  Physiol.,  1892,  Part  14. 

••  Arch.  f.  exp.  Path,  uud  Pharm.,  Bd.  31. 

'  In  regard  to  the  literature  of  the  blood-plates,  see  Lilienfeld,  Du  Bois- 
Reymond's  Archiv,  189'3.  and  R.  Mosen,  ibid.,  1893. 

*L.c. ;  also  LilienFeld,  "  Leukocyten  und  Blutgerinnung,"  Verhandl.  d. 
physioi.  Gesellsch.  zu  Berlin,  1893. 


152  THE  BLOOD. 


III.  The  Blood  as  a  Mixture  of  Plasma  and  Blood- 
corpuscles. 

The  blood  in  itself  is  a  thick,  sticky,  lighter  or  darker  red 
opaque  liquid  having  a  salty  taste  and  a  faint  odor  differing  in 
different  kinds  of  animals.  On  the  addition  of  sulphuric  acid  to 
the  blood  the  odor  is  more  pronounced.  In  adult  human  beings 
the  specific  gravity  ranges  between  1.045  and  1.075.  It  has  an 
average  of  1.058  for  grown  men  and  a  little  less  for  women. 
According  to  Schereenziss  ^  the  foetal  blood  has  a  lower  specific 
gravity  than  the  blood  of  grown  persons.  Lloyd  Jokes  '  found 
that  the  specific  gravity  is  highest  at  birth  and  lowest  in  children 
when  about  two  years  old  and  in  pregnant  women.  The  determi- 
nations of  Lloyd  Joxes,  Hammerschlag,^  and  others  show  that 
the  variation  of  the  specific  gravity,  dependent  upon  age  and  sex, 
corresponds  to  the  variation  in  the  quantity  of  hemoglobin. 

The  determination  of  the  specific  gravity  is  most  accurately  done 
by  means  of  the  pyknometer.  For  clinical  purposes  where  only 
small  amounts  are  available  it  is  best  to  proceed  with  the  method 
as  suggested  by  Hammerschlag.  Prepare  a  mixture  of  chloroform 
and  benzol  of  about  1.050  sp.  gr.  and  add  a  drop  of  the  blood  to 
this  mixture.  If  the  drop  rises  to  the  surface  then  add  benzol,  and 
if  it  sinks  add  chloroform.  Continue  this  until  the  drop  of  blood 
suspends  itself  midway  and  then  determine  the  specific  gravity  of 
the  mixture  by  means  of  an  areometer. 

The  reaction  of  the  blood  is  alkaline.  The  amount  of  alkali, 
calculated  as  Na2C03,  is  in  the  dog  about  2  (Zuntz^),  in  rabbits 
about  2.5  (Lassar"),  and  in  man  3.38-3.90  p.  m.  (v.  Jaksch'). 
The  alkaline  reaction  diminishes  outside  of  the  body,  and  indeed 
the  more  quickly  the  greater  the  original  alkalinity  of  the  blood. 
This  depends  on  the  formation  of  acid  in  the  blood,  in  which  the 
red  blood -corpuscles  seem  to  take  part  in  some  way  or  another. 
After  excessive  muscular  activity  the  alkalinity  is  diminished  on 

1  Cit.  from  Maly's  .Jahresber.,  Bd.  18,  S.  85. 

2  Journ.  of  Physiol.,  Vol.  8. 

»  Wien.  klin.  Wochensclir.,  1890,  and  Zeitschr.  f.  klin.  Med.,  Bd.  20. 
4  Centralbl.  f.  d.  med.  Wissensch.,Bd.  5,  S.  531  and  801. 

*  Pfltiger's  Archiv,  Bd.  9. 

•  Zeitschr.  f.  klin.  Med.,  Bd.  13,  S.  350. 


COAGULATION  OF  THE  BLOOD.  153 

account  of  the  formation  of  acid  in  the  muscles  (Peiper,"  Cohn- 
STEix '),  and  it  is  also  decreased  after  the  continuous  use  of  acids 
(Lassar,  FreudberCt"). 

The  color  of  the  blood  is  red — light  scarlet-red  in  the  arteries 
and  dark  bluish-red  in  the  veins.  Blood  free  from  oxygen "  is 
dichroitic,  dark  red  by  reflected  light,  and  green  by  transmitted 
light.  The  blood-coloring  matters  occur  in  the  blood-corpuscles. 
For  this  reason  blood  is  opaque  in  thin  layers  and  acts  as  a  "  deck- 
farbe. "  If  the  haemoglobin  is  removed  from  the  stroma  and 
dissolved  by  the  blood-liquid,  by  any  of  the  above-mentioned 
means  the  blood  becomes  transparent  and  acts  then  like  a  "  lake 
color."  Less  light  is  now  reflected  from  its  interior,  and  this 
laky  blood  is  therefore  darker  in  thicker  layers.  On  tlie  addi- 
tion of  salt  solutions  to  the  blood-corpuscles  they  shrink  and  more 
light  is  reflected  and  the  color  appears  lighter.  A  great  abundance 
of  red  corpuscles  makes  the  blood  darker,  while  by  diluting  with 
serum  or  by  a  greater  abundance  of  white  corpuscles  the  blood 
becomes  lighter  in  appearance.  The  different  colors  oi  arterial  and 
of  venous  blood  depend  on  the  varying  quantity  of  gas  contained  in 
these  two  varieties  of  blood  or,  better,  on  the  different  amounts  of 
oxyhjemoglobin  and  haemoglobin  they  contain. 

The  most  striking  property  of  blood  consists  in  its  coagulating 
within  a  shorter  or  longer  time,  but  as  a  rule  very  shortly  after 
leaving  the  vein.  Different  kinds  of  blood  coagulate  with  varying 
rapidity;  in  human  blood  the  first  marked  sign  of  coagulation  is 
seen  in  2-3  minutes,  and  within  7-8  minutes  the  blood  is 
thoroughly  converted  into  a  gelatinous  mass.  If  the  blood  is 
allowed  to  coagulate  slowly,  the  red  corpuscles  have  time  to  settle 
more  or  less  before  the  coagulation,  and  the  blood-clot  then  shows 
an  upper,  yellowish-gray  or  reddish-gray  layer  consisting  of  fibrin 
enclosing  chiefly  colorless  corpuscles.  This  layer  has  been  called 
crusta  injlammatoria  ov  phlogistica,  because  it  has  been  especially 
observed  in  inflammatory  processes,  and  is  considered  oue  of  the 
characteristics  of  them.  This  crusta  or  "  buffi/  coat  "  is  not  char- 
acteristic of  any  special  disease,  and  it  occurs  chiefly  when  the  blood 
coagulates  slowly  or  when  the  blood-corpuscles  settle  more  quickly 

1  Virchow's  Arch.,  Bd.  116. 

'  Ibid.,  Bd.  130,    which  has  also  references  to  the  works  of  Minkowski, 
Zuntz,  and  Geppert. 

^  Virchow's  Arch.,  Bd.  125. 


154  THE  BLOOD. 

than  usual,  A  bnffy  coat  is  often  observed  in  the  slow-coagulating 
eqnine  blood.  The  blood  from  the  capillaries  is  not  supposed  to 
have  the  power  of  coagalating. 

Coagulation  is  retarded  by  cooling,  by  diminishing  the  oxygen 
and  increasing  the  amount  of  carbon  dioxide,  which  is  the  reason 
that  venous  blood  and  to  a  much  higher  degree  blood  after  asphyxia- 
tion coagulates  more  slowly  than  arterial  blood.  The  coagalation 
may  be  retarded  or  prevented  by  the  addition  of  acids,  alkalies,  or 
ammonia,  even  in  small  quantities;  by  concentrated  solutions  of 
neutral  alkali  salts  and  alkaline  earths,  alkali  oxalates  and  fluorides; 
also  by  egg-albumin,  solutions  of  sugar  or  gum,  glycerin,  or  much 
water;  also  by  receiving  the  blood  in  oil.  Coagulation  may 
be  prevented  by  the  injection  of  an  albamose  solution  or  by 
an  infusion  of  the  leech  into  the  circulating  blood,  but  this  in- 
fusion of  the  leech  acts  in  the  same  way  on  blood  just  expelled. 
According  to  Dastre  '  the  coagulation  of  the  blood  of  a  dog  may 
be  gradually  prevented  by  a  series  of  bleedings  and  re-injection  of 
the  defibrinated  blood.  The  reason  for  this  non-coagulation  lies  in 
the  lack  of  fibrinogen.  The  coagulation  may  be  facilitated  by  rais- 
ing the  temperature;  by  contact  with  foreign  bodies,  to  which  the 
blood  adheres;  by  stirring  or  beating  it;  by  admission  of  air;  by 
diluting  with  very  small  amounts  of  water;  by  the  addition  of 
platinum-black  or  finely  powdered  carbon;  by  the  addition  of  laky 
blood,  which  does  not  act  by  the  presence  of  dissolved  blood-coloring 
matters,  but  by  the  stromata  of  the  blood-corpuscles  (Wool- 
DRiDGE^),  and  also  by  the  addition  of  the  leucocytes  from  the 
lymphatic  glands,  or  a  watery  saline  extract  of  the  lymphatic 
glands,  testicles,  or  thymus.  The  active  constituent  of  such  a 
watery  extract  is  the  nucleoproteid  called  tissue  fibrinogen  or  nucleo- 
histon. 

An  important  question  to  answer  is  why  the  blood  remains  fluid 
in  the  circulation  while  it  quickly  coagulates  when  it  leaves  the  cir- 
culation. 

When  the  blood  leaves  the  vein  it  comes  under  new,  abnormal 
conditions.  It  cools  off,  comes  in  contact  with  the  air,  its  motion 
stops,  and  it  is  deprived  of  the  influence  of  the  living  walls  of  the 
vessels.  That  the  cooling  is  not  the  reason  of  the  coagulation  is 
proved   by  the   fact  that   cooling   is  a   good  means  of   retarding 

'  Compt.  rend  d.  soc.  biol.,  Tome  45,  and  Arch,  de  physiol.,  Ser.  5,  Tome  5. 
2  Die  Gerinnung  des  Blutes  (published  by  M.  V.  Frey,  Leipzig,  1891). 


COAGULATION  OF  THE  BLOOD.  155 

coagulation.  That  the  contact  with  air  is  not  essential  is  shown  by 
the  fact  that  when  blood  is  collected  over  mercury,  so  that  it  cannot 
absorb  or  expel  any  gas,  it  likewise  coagulates.  That  the  cessation 
of  the  motion  does  not  cause  the  coagulation  follows,  since  blood 
collected  over  mercury  coagulates  whether  it  is  shaken  or  not,  and 
further  from  the  fact  that  motion,  such  as  beating  the  blood, 
facilitates  the  coagulation. 

The  reason  why  blood  coagulates  on  leaving  the  body  is  therefore 
to  be  sought  for  in  the  influence  which  the  walls  of  the  living  and 
entire  blood-vessels  exert  upon  it.  These  views  are  derived  from 
the  observations  of  many  investigators.  From  the  observations  of 
Hewson",'  Lister,"  and  Fredericq'  it  is  known  that  when  a  veni 
full  of  blood  is  ligatured  at  the  two  ends  and  removed  from  the 
body,  the  blood  may  remain  fluid  for  a  long  time.  Brucke^ 
allowed  the  heart  removed  from  a  tortoise  to  beat  at  0°  C,  and 
found  that  the  blood  remained  uncoagulated  for  some  days.  The 
blood  from  another  heart  quickly  coagulated  when  collected  over 
mercury.  In  a  dead  heart,  as  also  in  a  dead  blood-vessel,  the  blood 
soon  coagulates,  and  also  when  the  walls  of  the  vessel  are  changed 
by  pathological  processes. 

"What  then  is  the  influence  which  the  walls  of  the  vessels  exert 
on  the  liquidity  of  the  circulating  blood  ?  Freuxd  °  has  found 
that  the  blood  remains  fluid  when  collected  by  means  of  a  greased 
canula  under  oil  or  in  a  vessel  smeared  with  vaseline.  If  the  blood 
collected  in  a  greased  vessel  be  beaten  with  a  glass  rod  previously 
oiled,  it  does  not  coagulate,  but  it  quickly  coagulates  on  beating  it 
with  an  unoiled  glass  rod  or  when  it  is  poured  into  a  vessel  not 
greased.  The  non-coagulability  of  blood  collected  under  oil  has 
been  confirmed  later  by  Haycraft  and  Carlier.*  Freund 
found  on  further  investigating  that  the  evaporation  of  the  upper 
layers  of  blood  or  +heir  contamination  with  small  quantities  of  dust 
causes  a  coagulation  even  in  a  vessel  treated  with  vaseline.  Accord- 
ing to  Freund,  it  is  this  adhesion  between  the  blood  or  between  its 
form-elements  and  a  foreign  substance — and   the  diseased  walls  of 

'  Hewson's  works,  ed.  by  Gulliver,  London,  1876. 
5  Proc.  Roy.  Soc,  Vol.  12. 

*  Reclierches  sur  la  constitution  du  plasma  sanguin.     Gand,  1878. 

*  Vircliow's  Archiv,  Bd.  12. 
*Wien.  med.  Jalirb.,  J886. 

'  Journal  of  Anat.  and  Physiol.,  Vol.  22, 


156  THE  BLOOD. 

the  vessel  also  act  as  such — that  gives  the  impulse  towards  coagula- 
tion, while  the  lack  of  adhesion  prevents  the  blood  from  coagulat- 
ing. This  adhesion  of  the  form-elements  of  the  blood  to  certain 
foreign  substances  seems  to  induce  changes  which  apparently  stand 
in  a  certain  relationship  to  the  coagulation  of  the  blood. 

The  views  in  regard  to  these  changes  are  very  contradictory. 
According  to  Alex.  Schmidt  '  and  the  Dorpat  school,  an  abun- 
dant destruction  of  the  leucocytes  takes  place  in  coagulation,  and 
important  constituents  for  the  coagulation  of  the  fibrin  pass  into 
the  plasma.  According  to  Lowit"  and  other  experimenters  the 
essential  is  not  a  destruction  of  the  leucocytes,  but  an  elimination  of 
constituents  from  the  cells  into  the  plasma.  This  process  is  called 
plasmoschisis  by  Lowit, 

According  to  Bizzozoro  '  and  others,  the  leucocytes  are  not  the 
starting-point  in  the  fibrin  formation,  but  rather  the  blood-plates. 
This  view  is  in  good  accord  with  the  recent  investigations  of 
LiLiEiSTFELD  and  MosE]sr.^  According  to  Lilienfeld  the  blood- 
plates  are  considered  as  derived  from  the  cell  nucleus  and  according 
to  this  author  the  fibrin  coagulation  is  a  function  of  the  cell 
nucleus.  This  view  is  contradicted  by  Grtesbach^  because, 
as  he  claims,  the  nucleus  cannot  take  part  in  the  coagulation, 
but  that  in  the  first  place  a  part  of  the  cell  body  is  destroyed 
by  plasmoschises,  and  this  even  while  the  nucleus  remains  still 
intact. 

Wooldridge*  takes  a  very  peculiar  position  in  regard  to  this 
question,  namely,  he  considers  the  form-elements  as  only  of  second- 
ary importance  in  coagulation.  As  found  by  him,  a  peptone- 
plasma,  which  has  been  freed  from  all  form-constituents  by  means 
of  centrifugal  force,  yields  abundant  fibrin  when  it  is  not  separated 

'  Pflilger's  Archiv,  Bd.  11.  The  works  of  Alex.  Schmidt  are  found  in  Arch. 
f.  Anat.  und  Physiol,  1861,  1862;  Pfltlger's  Arch.,  Bdd.  6,  9,  11,  13.  See 
especially  Alex.  Schmidt,  Zur  Blutlehre  (Leipzig,  1892),  which  also  gives  the 
work  of  his  pupils. 

^  Wien.  Sitzungsber.,  Bdd.  89  and  90,  and  Prager  med.  Wochenschr.,  1889. 
Referred  to  in  Centralbl.  f.  d.  med.  Wissensch.,  Bd.  28,  S.265. 

3  Virchow's  Arch.,  Bd.  90;  Centralbl.  f.  d.  med.  Wissensch.,  1882,  S.  17, 
161,  353,  563;  ibid.,  1883;  Virchow's  Festschrift,  1891. 

"L.c. 

^  Pflilger's  Archiv,  Bd.  50,  and  Centralbl.  f.  d.  med.  Wissensch.,  1892, 
S.  497. 

6L.C. 


SCHMWrS  THEORY  OF  COAGULATION.  157 

from  a  substance  which  precij^itates  on  cooling.  This  substance, 
which  WoOLDRiDGE  has  called  A-fibrinogen,  seems  to  be  identical 
with  Lowit's  globulin-plates,  and  it  consists  in  all  probability  of  a 
nucleoproteid,  which  is  perhaps  identical  with  prothrombin  as 
isolated  by  Pekelhaeing,'  As  this  nucleoproteid  originates, 
acording  to  the  unanimous  view  of  several  investigators,  from  the 
form-elements  of  the  blood,  either  the  blood-plates  or  leucocytes, 
Wooldridge's  experiments  do  not  seem  to  contradict  the  generally 
accepted  view  that  the  form-elements  of  the  blood  are  of  the 
greatest  importance  in  the  coagulation  of  the  same. 

The  views  are  greatly  divided  in  regard  to  those  bodies  which  are 
eliminated  from  the  form-elements  of  the  blood  before  and  during 
coagulation. 

According  to  Alex.  Schmidt'  the  leucocytes,  like  all  cells, 
contain  two  chief  groups  of  constituents,  one  of  which  accelerates 
coagulation,  while  the  other  retards  or  hinders  it.  The  first  may 
be  extracted  from  the  cells  by  alcohol,  while  the  other  cannot  be 
extracted.  Blood-plasma  contains  only  traces  of  thrombin,  accord- 
ing to  Schmidt,  but  does  contain  its  antecedent,  prothrombin.  The 
bodies  which  accelerate  coagulation  are  neither  thrombin  nor  pro- 
thrombin, but  they  act  in  this  wise  in  that  they  split  off  thrombin 
from  the  prothrombin.  On  this  account  they  are  called  zymoplastic 
substances  by  Alex.  Schmidt.  The  nature  of  these  bodies  is 
unknown,  and  according  to  Lilienfeld"  KH^PO,  is  found  amongst 
them,  and  Schmidt  has  given  no  notice  of  their  behavior  to  the 
lime-salts,  which  have  been  found  to  have  zymoplastic  activity  by 
other  investigators.  The  constituents  of  the  cells  which  hinder 
coagulation  and  which  are  insoluble  in  alcohol-ether  are  compound 
proteids  and  have  been  called  cytoglohin  and  preglohilin  by 
Schmidt.  The  retarding  action  of  these  bodies  may  be  suppressed 
by  the  addition  of  zymoplastic  substances,  and  the  yield  of  fibrin  on 
coagulation  in  this  case  is  much  greater  than  in  the  absence  of  the 
compound  proteid-retarding  coagulation.  This  last  supplies  the 
material  from  which  the  fibrin  is  produced.  The  process  is,  accord- 
ing to  Schmidt,  as  follows:  The  preglobulin  first  splits,  yielding 
serglobulin,  then  from  this  the  fibrinogen  is  derived,  and  from  this 

'  Ueber  das  Fibrinferment.   Verhandl.   d.   kon.   Akad.  van.   Wetensch.  te 
Amsterdam,  Deel  1,  No.  3,  1893. 
2  Zur  Blutlehre. 
*  Weitere  BeitrSge  zur  Kenntniss  der  Blutgerinnung.     Berlin,  1893. 


158  THE  BLOOD. 

latter  the  fibrin  is  produced.  The  object  of  the  thrombin  is  two- 
fold. The  thrombin  first  splits  the  fibrinogen  from  the  paraglobulin 
and  then  converts  the  fibrinogen  into  fibrin.  Alex.  Schmidt  is 
now  agreed  with  most  investigators  that  fibrin  is  produced  by  an 
enzymotic  transformation  of  the  fibrinogen,  and  the  influence  of  the 
serglobalin,  as  observed  by  him  on  the  quantity  of  fibrin  formed,  he 
explains  now  by  the  assumption  that  the  fibrinogen  is  produced  by 
the  splitting  of  the  serglobulin. 

According  to  Schmidt  the  retarding  action  of  the  cells  is 
prominent  during  life,  while  the  accelerating  action  is  especially 
pronounced  outside  of  the  body  or  by  coming  in  contact  with  foreign 
bodies.  The  parenchymous  masses  of  the  organs  and  tissues,  through 
which  the  blood  flows  in  the  capillaries,  are  those  cell  masses  which 
serve  to  keep  the  blood  fluid  during  life  (Alex.  Schmidt). 

LiLiENFELD  '  has  given  further  proofs  as  to  the  occurrence  in 
the  form-elements  of  the  blood  of  bodies  which  accelerate  or  retard 
the  coagulation.  According  to  this  author  the  nature  of  these 
bodies  is  very  markedly  difl'erent  from  Schmidt's  idea.  "While, 
according  to  Schmidt,  the  coagulation  accelerators  are  bodies  solu- 
ble in  alcohol,  and  the  proteids  exhausted  with  alcohol  only  act 
retardingly  on  coagulation,  Lilienfeld  states  that  the  substance 
which  acts  acceleratingly  and  retardingly  on  coagulation  consists  of 
a  nucleoproteid,  namely,  nucleohiston.  Nucleohiston  readily  splits 
into  leuconuclein  and  histon,  the  first  of  which  acts  as  a  coagulation 
excitant,  while  the  other,  introduced  into  the  blood- vascular  s;^stem, 
either  intravascular  or  extravascular,  robs  the  blood  of  its  property 
of  coagulating.  Introduced  into  the  circulatory  system  the  nucleo- 
histon splits  into  its  two  components.  It  therefore  causes  extensive 
coagulation  on  one  side  and  makes  the  remainder  of  the  blood 
uncoagulable  on  the  other. 

Lilienfeld^  is  of  the  view  that  fibrinogen  does  not  exist  dis- 
solved in  the  plasma  of  the  circulating  blood.  It  passes  into  the 
plasma  on  the  disintegration  of  the  leucocytes  and  originates  from 
the  substance  of  cell  nuclei  of  the  leucocytes.  Nucleohiston  may 
be  directly  transformed  into  fibrin.     Lilienfeld's  theory  at  the 

'  See  Lilienfeld :  Ueber  Leukocyten  und  Blutgerinnung.  Verhandl.  d. 
physiol.  Gesellsch.  zu  Berlin,  No.  11,  1892;  Ueber  den  flnssigen  Zustand  des 
Blates,  etc.,  ibid.,  No.  16,  1892;  and  Weitere  Beitrage  zur  Kentnisse  der  Blut- 
gerinnung, ibid.,  July,  1893. 

2  Zeitschr.  f.  pliysiol.  Chem.,  Bd.  20. 


LILIENFELD'S   THEORY  OF  COAGULATION.  159 

present  time  is  that  on  leaving  the  veins  the  leucocytes  of  the  blood 
are  destroyed  or  the  naclein  substance  passes  into  the  plasma.  This 
uuclein  substance  splits  the  fibrinogen  into  thronibosin  and  a  sub- 
stance which  gives  the  biuret  reaction.  The  throrabosin  combines 
with  the  soluble  calcium  salts,  forming  fibrin.  The  leuconuclein  is 
therefore  the  real  coagulation  exciter  (not  the  fibrin  ferment);  the 
histou  split  from  the  nucleohiston  has,  on  the  contrary,  a  retarding 
action  on  coagulation.  As  the  blood-plates  contain  nuclein,  they 
as  well  as  the  leucocytes  take  an  active  part  in  the  fibrin  coagula- 
tion. 

Brucke  showed  long  ago  that  fibrin  left  an  ash  containing  cal- 
cium phosphate.  The  fact  that  calcium  salts  may  facilitate  or  even 
cause  a  coagulation  in  liquids  poor  in  ferment  has  been  known  for 
several  years  through  the  researches  of  the  author,'  Green,' 
KiNGER,  and  Saixsbury.^  The  necessity  of  the  lime-salts  for 
coagulation  was  first  shown  positively  by  the  important  investiga- 
tions of  Arthus  and  Pages. ^  In  regard  to  the  manner  in  which 
the  lime-salts  act  we  have  only  lately  been  able  to  come  to  a  result. 

Freund  °  has  given  the  following  explanation  for  the  action  of 
lime-salts:  The  alkali  phosphates  pass  from  the  form-elements  into 
the  plasma,  which  is  richer  in  lime-salts  and  forms  calcium  phos- 
phate. If  the  quantity  of  calcium  phosphate  in  the  plasma  or  other 
coagnlable  liquid  is  so  great  that  it  cannot  be  kept  completely  in 
solution,  then,  according  to  Freund,  the  separation  of  the  excess 
is  the  cause  of  a  part  of  the  proteids  becoming  insoluble,  that  is, 
a  cause  for  coagulation.  Weighty  objections  can  be  made  against 
this  view,  and  it  is  also  confuted  by  Latschenberger  "  and 
Strauch.' 

According  to  Pekelharing  *  the  process  is  as  follows:  The 
prothrombin  is  converted  into  thrombin  by  the  action  of  the  soluble 
lime-salts  and  fluids  otherwise  capable  of  coagulation,  which  contains 
only  prothrombin,  but  no  thrombin  can  therefore  be  brought  to 

1  Nova  Acta  reg.  Soc.  Scient   Upsala,  Ser.  Ill,  Vol.  10,  1879. 
«  Journ.  of  Physiol.,  Vol.  8. 

*  Ibkl.,  Vols.  11  and    3. 

*  M.  Arthus,  Recherches  sur  la  Coagulation  du  sang.,  Paris,  1890;  Arthus 
et  Pag^s;  Nouvelle  Theorie,  etc.,  Arch,  de  Physiol.  (5),  Tome  2,  1890. 

»  Wien.  med.  Jahrb.,  1888,  S.  259. 

«  Ibid.,  1888,  S.  479,  and  Wien.  med.  Wochenschr.,  1889. 

'  Dissertation.     Dorpat,  1889.     Ref.  Maly's  Jahresber.,  Bd.  19. 

8  Virchovp's  Festschrift,  Bd.  1,  1891. 


160  THE  BLOOD. 

coagulation  by  the  addition  of  soluble  lime-salts.  Thrombin, 
according  to  Pekelharing,  is  a  lime  combination  of  prothrombin, 
and  the  process  of  coagulation  consists  in  that  the  thrombin  carries 
the  lime  to  the  fibrinogen,  which  is  converted  into  the  insoluble 
combination  of  fibrin  and  lime.  The  thrombin  is  hereby  recon- 
verted into  prothrombin,  which  again  takes  up  lime  to  be  trans- 
formed into  thrombin,  which  gives  up  its  lime  to  a  new  portion  of 
fibrinogen,  converting  it  into  fibrin;  and  so  on.  This  explanation 
of  the  process  is  only  a  hypothesis,  but  the  formation  of  thrombin 
from  a  mother-substance  by  the  action  of  soluble  lime-salts  is,  on 
the  contrary,  a  positively  proven  fact. 

It  is  a  question  whether  the  prothrombin  exists  in  the  plasma 
of  the  circulating  blood  or  whether  it  is  a  body  eliminated  from  the 
form-elements  before  coagulation.  Alex.  Schmidt  claims  that  the 
circulating  plasma  contains  prothrombin,  but  Pekelharing  dis- 
claims this.  Blood-plasma  obtained  by  means  of  leech  infusion 
does  not  coagulate  on  the  addition  of  lime-salts,  but  does  on  the 
addition  of  a  prothrombin  solution.  The  form-elements,  especially 
the  blood-plates,  are  particularly  well  preserved  by  such  plasma; 
and  according  to  Pekelhari^stg  it  is  probable  that  the  circulating 
plasma  does  not  contain  any  mentionable  amounts  of  prothrombin, 
and  that  this  body  emerges  from  the  form-elements,  perhaps  the 
blood-plates,  before  coagulation. 

In  opposition  to  the  view  of  Alex.  Schmidt,  who  considers  the 
fibrin  coagulation  as  an  enzymotic  process,  Wooldridge  '  is  of  the 
opinion  that  the  fibrin  ferment  is  not  the  cause  of  the  coagulatiou, 
but  is  a  product  of  the  chemical  processes  taking  place  during 
coagulation.  Wooldridge  claims,  on  the  contrary,  that  lecithin 
and  protein  substances  containing  lecithin  are  of  the  greatest  im- 
portance in  the  coagulation.  This  product  is  obtained  by  cooling 
the  peptone-plasma  which  has  been  centrif  ugated,  and  the  substance 
which  separates  has  been  called  by  Wooldridge  ^-fibrinogen. 
The  plasma,  according  to  Wooldridge,  contains  in  itself  all  quali- 
ties necessary  to  produce  a  coagulation,  and  the  form-elements  are 
only  of  a  secondary  importance.  Peptone-plasma  which  has  been 
centrifugated  and  which  is  entirely  free  from  form-elements,  but 
contains  the  ^-fibrinogen,  coagulates  on  diluting  with  water,  by 
the  passage  of  carbon  dioxide  through  the  liquid,  or  after  the  addi-* 

1  The  summary  of  the  observations  of  Wooldridge  are  found  in  the  pre- 
viously cited  publication,  "  Die  Gerinnuug  des  Blutes  "  (M.  v.  Frey,  1891). 


INTRAVASCULAR   COAOULATION.  161 

tion  of  a  little  acetic  acid,  and  the  fibrin  ferment  is  thereby  formed. 
WooLDRiDGE  designates  as  C'-fibrinogen  the  ordinary  fibrinogen 
isolated  by  the  method  suggested  on  page  113.  This  fibrinogen 
occurs  indeed  in  transudations,  but  it  only  occurs  in  the  peptone- 
plasma  in  very  small  quantities.  A  third  fibrinogen  occurs  in  the 
greatest  amounts  in  the  peptone-plasma,  and  this  is  the  mother- 
substance  of  the  C-fibrinogen,  and  called  ^-fibrinogen  by  WoOL- 
DRIDGE.  The  .^-fibrinogen  is  converted  into  fibrin  by  lecithin  and 
leucocytes  from  the  lymphatic  glands,  but  not  by  fibrin  ferment  or 
blood-serum.  After  the  previous  action  of  serum  or  fibrin  ferment 
the  ^-fibrinogen  yields  fibrin  on  diluting  with  water.  The  one 
most  essential  for  the  fibrin  coagulation  is,  according  to  Wool- 
DRIDGE,  a  reciprocal  action  between  A-  and  ^-fibrinogen.  An 
exchange  of  lecithin  from  the  ^-fibrinogen  to  the  ^-fibrinogen 
takes  place. 

Halliburton^  '  has  opposed  weighty  arguments  to  this  theory 
It  is  also  difficult  to  find  in  Wooldridge's  discussion  conclusive 
proofs  for  the  above  views,  and  the  experiments  by  which  they  are 
supported  are  interpreted  with  difficulty.  On  account  of  the  very 
complicated  condition  of  the  question  of  coagulation  at  the  present 
time,  it  is  impovssible  to  draw  any  definite  conclusions  from  the 
observations  of  Wooldridge. 

Intravascular  coagulation.  It  has  been  shown  by  Alex. 
Schmidt  and  his  students,  as  also  by  Wooldridge,  Wright,''  and 
others,  that  an  intravascular  coagulation  may  be  brought  about  by 
the  intravenous  injection  into  the  circulating  blood  of  a  large 
quantity  of  a  thrombin  solution,  as  also  by  the  injection  of  leuco- 
cytes or  tissue  fibrinogen  (impure  nucleohiston).  In  rabbits  this 
coagulation  may  extend  through  the  entire  vascular  system,  while 
in  dogs  it  is  ordinarily  confined  to  the  portal  system.  The  blood 
in  the  other  parts  of  the  vascular  system  has  generally  a  decreased 
coagulat  ability.  If  too  little  of  the  above-mentioned  bodies  be 
injected,  then  we  only  observe  a  marked  retarding  tendency  in  the 
coagulation  of  the  blood.  According  to  Wooldridge  we  can. 
generally  maintain  that  after  a  short  stage  of  accelerated  coagula- 

'  Journal  of  Physiol.,  Vol.  9. 

'  A  study  of  the  intravascular  coagulation,  etc.,  Proceed,  of  the  Roy.  Irish 
Acad.  (3),  Vol.  2;  see  also  Wright  :  Lecture  on  tissue  or  cellfibrinogen,  The 
Lancet;  1893;  and  Wooldridge's  Method  of  producing  immunity,  etc.,  Brit. 
Med.  Journal,  Sept.  1891. 


162  THE  BLOOD. 

laility,  which  may  lead  to  a  total  or  partial  intravascular  coagulation, 
a  second  stage  of  a  diminished  or  even  arrested  coagulability  of  the 
blood  follows.  The  first  stage  is  designated  as  the  j^dsiYi'ye  and  the 
other  the  negative  pliase  of  coagulation.  These  statements  have 
been  confirmed  by  several  investigators. 

There  is  no  doubt  that  the  positive  phase  is  brought  about  by 
an  abundant  introduction  of  thrombin,  or  by  a  rapid  and  abundant 
formation  of  the  same.  According  to  Ales.  Schmidt,  the  zymo- 
plastic  substances  soluble  in  alcohol  are  active  in  these  processes, 
while  according  to  the  investigations  of  PEKELHARii>fG  this  action 
is  caused  more  likely  by  the  leuconucleins,  split  ofE  from  the 
nucleohiston.  According  to  Wooldeidge,  his  tissue  fibrinogen 
does  not  produce  any  intravascular  coagulation  if  it  is  freed  from 
contaminating  bodies  by  means  of  alcohol.  This  corresponds  with 
the  statements  of  Alex.  Schmidt,  but  still  further  investigations 
are  necessary. 

In  regard  to  the  origin  of  the  negative  phase,  attention  has  been 
called  to  histon,  which  has  a  retarding  action  on  coagulation,  and 
which  is  split  off  from  the  nucleohiston.  According  to  Weight 
and  Pekelhaeing,  the  retarding  substances  are  albumoses,  which 
are  formed  in  the  decomposition  of  the  nucleoproteids.  Albumoses 
have  been  detected  by  these  investigators  in  the  blood  of  animals 
during  this  phase,  and  also  in  the  urine  after  intravenous  injection 
of  tissue  fibrinogen.  According  to  Pekelhaeing,  the  albumoses 
act  by  combining  with  the  calcium  of  the  blood,  and  in  this  wise 
preventing  coagulation.  Geosjean  '  has  found  that  blood  which 
has  regained  its  property  of  coagulation  24  hours  after  an  albumose 
injection  will  not  have  its  coagulation  prevented  by  a  fresh  injec- 
tion of  albumose,  hence  it  is  immune  against  albumose  injection. 
He  also  infers  from  these  experiments  that  the  albumose,  to  have  a 
preventing  action  at  all,  must  first  undergo  a  change  in  the 
organism.  This  has  been  further  studied  by  Contejean,"  who 
finds  that  under  the  influence  of  injected  albumose  a  special  sub- 
stance is  secreted  in  the  animal  body  which  prevents  coagulation. 
This  seems  to  be  brought  about  by  means  of  the  liver  and  intestine. 
A  dog  may  be  made  immune  against  the  preventive  action  of 
albumose  by  previously  injecting  a  small  quantity  of  "  peptonized 
blood"  into  the  vessels.     The  body  hereby  loses  its  property  of 

1  Travaux  du  laboratoire  de  L.  Frederiq.    Tome  4.     Liege,  1893. 

2  Arch,  de  Physiol.,  Ser.  5,  Tome  7. 


QUANTITATIVE  COMPOSITION  OF  THE  BLOOD.         163 

producing  substances  which  prevent  coagulation  under  tlie  influence 
of  injected  albumoses. 

Weight  gives  as  reason  why  the  intravascnhir  coagulation  of 
the  blood  of  a  dog  is  ordinarily  confined  to  the  portal  system,  in 
the  fact  that  it  contains  larger  quantities  of  carbon  dioxide.  An 
increased  quantity  of  carbon  dioxide  in  the  blood  favors  the  appear- 
ance of  the  positive  phase,  and  an  intravascular  coagulation  may  be 
produced  in  dogs,  who  are  asphyxiated  by  clamping  the  ti'achea,  by 
injecting  tissue  fibrinogen  (impure  nucleohiston). 

The  gases  of  the  blood  will  be  treated  of  in  Chapter  XVII  (on 
respiration) . 

IV.  The  Quantitative  Composition  of  the  Blood. 

The  quantitative  analysis  of  blood  cannot  be  of  value  for  the 
blood  as  an  entirety.  We  must  ascertain  on  one  side  the  relation- 
ship of  the  plasma  and  blood-corpuscles  to  each  other,  and  on  the 
other  side  the  constitution  of  each  of  these  two  chief  constituents. 
The  difficulties  which  stand  in  the  way  of  such  a  task,  especially  in 
regard  to  the  living,  non-coagulated  blood,  have  not  been  removed. 
Since  the  constitution  of  the  blood  may  differ  not  only  in  different 
vascular  regions,  but  also  in  the  same  region  under  different  cir- 
cumstances, which  renders  also  a  number  of  blood  analyses  neces- 
sary, it  can  hardly  appear  remarkable  that  our  knowledge  of  the 
constitution  of  the  blood  is  still  relatively  limited. 

The  relative  volume  of  blood-corpuscles  and  serum  in  defibri- 
nated  blood  may  be  determined,  according  to  L,  and  M.  Bleib- 
TREU,'  by  various  methods  if  the  defibriuated  blood  is  mixed  with 
different  proportions  of  JSTaCl  solutions  of  6  p.  m.  (1  vol.  salt 
solution  to  1  vol.  blood),  the  blood-corpuscles  allowed  to  settle  to 
the  bottom  or  facilitated  by  centrifugal  force,  and  the  clear  super- 
natant mixture  of  serum  and  common-salt  solution  sij^honed  off. 
The  methods  are  as  follows : 

1.  Determine  the  quantity  of  nitrogen  in  at  least  two  different 
portions  of  the  mixture  of  serum  and  salt  solution  by  means  of 
Kjeldahl's  method  and  calculate  the  quantity  of  proteid  corre- 
sponding thereto  by  multiplying  with  6,25,  and  the  relative  volume 
of  blood  X  and  also  the  volume  of  the  structural  elements  (1  —  .^') 
is  found  by  the  following  equation : 

(e,  -  e,)x  =  ~\  -  ^e,. 
'  Pfliiger's  Archiv,  Bd.  51. 


164  THE  BLOOD. 

In  this  equation  (for  mixtures  1  and  2),  h^  or  J,  represents  the 
volume  of  blood  in  the  mixture,  s^  or  s^  the  volume  of  salt  solution, 
and  gj  or  e^  the  quantity  of  j)roteid  in  a  certain  volume  of  each 
m.ixture. 

2.  Determine  the  specific  gravity  of  the  blood-serum,  the  salt 
solution  and  at  least  one  of  the  mixtures  of  serum  and  salt  solution 
by  means  of  a  pyknometer.  The  relative  volume  of  serum  x  is 
found  in  this  by  the  following  equations: 

-I    '^-  ^ 

In  this  equation  s,  and  J  represent  the  volumes  of  salt  solution  and 
blood  mixed.  S  represents  the  sjjecific  gravity  of  the  obtained 
serum  and  salt  solution  obtained  on  allowing  the  blood-corpuscles 
to  settle,  iS'd  the  sp.  gr.  of  the  serum,  and  K  that  of  the  salt  solu- 
tion. 

For  horses'  blood,  two  other,  shorter  methods  may  be  made  use 
of  (see  the  original  article). 

Hambueger  '  raises  special  objections  to  the  above  methods,  but 
according  to  Bleibtreu  they  are  of  no  practical  importance  as 
long  as  the  blood  is  not  diluted  with  more  than  an  equal  volume  of 
the  salt  solution.^ 

Etkman"  '  and  Hedi]!^  '  have  raised  important  objections  to 
BleibtPlEu's  method.  They  have  shown  by  different  methods  that 
the  red  corpuscles  are  not  changed  in  volume  only  in  such  salt 
solutions  which  are  isotonic  with  the  plasma  or  serum.  (In  regard 
to  the  osmotic  pressure  of  the  blood-corpuscles  and  the  isotonic 
relationship  of  salt  solutions  and  serum,  see  Hamburger  \)  Such 
a  solution  is  not  one  containing  6  p.  m.  NaCl,  for  human,  ox,  or 
horse's  blood,  but  rather  one  containing  about  9  p.  m.  ISaCl 
(Lackschewitz  ').  The  blood-corpuscles  swell  up  in  a  solution  of 
6  p.  m.  NaCl,  and  therefore  an  abundant  exchange  of  constituents 
takes  place  between  them  and  the  salt  solution;  hence  Bleibtreu's 
method  is  incorrect.  Hedin,  as  before  him  Bieejstacki,'^  could  not 
obtain  corresponding  results  of  the  volume  of  corpuscles  calculated 
from  the  nitrogen  determined.  The  question  arises  whether  this 
method  is  available  if  we  use  an  isotonic  salt  solution.  According 
to  Hedin  this  is  not  true,  as  he  has  found  that  the  red  blood- 
corpuscles  take  up  considerable  quantities  of  plasma  proteid,  even 

1  Centralbl.  f.  PliysioL,  Bd.  7,  S.  161. 

*  See  M.  Bleibtreu,  Pfliiger's  Archiv,  Bd.  55. 

2  Pfliiger's  Arch.,  Bd.  60. 

*  Ihid.,  and  Skand.  Arch.  f.  Physiol.,  Bd.  5. 
5  Virchow's  Arch. ,  Bd.  140,  S.  505. 

«  Pfluger's  Arch.,  Bd.  59. 

'  Zeitschr.  f.  physiol.  Chem.,  Bd.  19. 


QUANTITATIVE  BLOOD  ANALYSIS.  165 

in  isotonic  common-salt  solntion,  without  changing  their  volume. 
This  statement  is  disputed  by  M.  Bleibtreu,'  and  the  analyses 
made  by  using  an  isotonic  salt  solution,  although  not  numerous, 
have  led  to  very  good  results. 

For  clinical  jiurposes  the  relative  volume  of  corpuscles  in  the 
blood  may  be  determined  by  the  use  of  a  small  centrifuge  called 
hcBmatocrit,  constructed  b}'  Blix  and  described  and  tested  by 
Hedix.*  a  measured  quantity  of  blood  is  mixed  with  a  known 
volume  (best  an  equal  volume)  of  a  fluid  which  prevents  coagula- 
tion. This  mixture  is  introduced  into  a  tube  and  then  centrif  uged. 
Hedix  uses  Muller's  solution  as  a  diluting  fluid  and  Dalaxd  ^  a 
2.5^  solution  of  potassium  bichromate.  After  complete  centrif u- 
gation  the  layer  of  blood-corpuscles  is  read  off  on  the  graduated 
tube,  and  the  volume  of  blood-corpuscles  calculated  in  100  vols,  of 
the  blood  therefrom.  By  means  of  comparative  counts  Hedix  and 
Dalaxd  have  found  that  an  ajDproximately  constant  relation  exists 
between  the  volume  of  the  layer  of  blood-corpuscles  and  the  number 
of  red  corpuscles  under  physiological  conditions,  so  that  the  number 
of  corpuscles  may  be  calculated  from  the  volume.  Dalaxd  has 
shown  that  such  a  calculation  gives  approximate  results  also  in 
disease,  when  the  size  of  the  blood-corpuscles  does  not  essentially 
deviate  from  the  normal.  In  certain  diseases,  such  as  pernicious 
ansmia,  this  method  gives  such  inaccurate  results  that  it  cannot  be 
used.  The  uselessuess  of  this  method  for  the  exact  estimation  of 
the  volume  of  blood-corpuscles  has  been  demonstrated*  by  L.  Bleib- 
treu." Etkmax  as  well  as  Heuix  repudiate  the  objections  made 
by  Bleibtreu  against  the  hematocrit  method;  but  they  also  show 
that  Muller's  soliition  as  well  as  the  2.5^  potassium  bichromate 
solution  causes  the  blood-corpuscles  to  swell  up,  and  hence  lead  to 
incorrect  results.  According  to  Hedix,  in  working  with  the 
hgematocrit  dilute  the  blood,  which  is  kejot  fluid  by  a  1  p.  m. 
oxalate  solution,  with  an  equal  volume  of  a  solution  containing 
9  p.  m.  XaCl.  Under  these  conditions  the  determination  of  the 
volume  of  blood-corpuscles  by  the  haBmatocrit  method  is  very 
serviceable.  This  method  is  not  available  for  the  exact  determina- 
tion of  the  volume  of  corpuscles,  because  the  sediment  of  blood- 
corpuscles  to  all  appearances  does  not  consist  only  of  blood-cor- 
puscles, but  also  some  plasma. 

If  we  know  the  relationship  between  the  volnme  of  corpuscles 
and  blood  liquid  we  can  also  estimate  the  relative  weights  by 
determining  the  specific  gravity  of  the  blood  and  serum.  In  direct 
determinations  of  the  proportion  by  weight  we  proceed  in  the  fol- 
lowing way : 

'  Pfliiger's  Arch.,  Bd.  60. 

«  Skandinav.  Arch.  f.  Physiol.,  Bd.  2,  S.  134  and  361. 

3  Fortschritte  d.  Med.,  Bd.  9,  1891. 

*  Biernacki,  Zeitscbr.  f.  physiol.  Chem.,  Bd.  19. 

"Berl.  klin.  Wochenschr.,  1893,  No.  30. 


166  THE  BLOOD. 

If  any  substance  isfonnd  in  the  blood  which  belongs  exclusively 
to  the  plasma  and  does  not  occur  in  the  blood-corpnscles,  then  the 
amount  of  plasma  contained  in  the  blood  may  be  calculated  if  we 
determine  the  amount  of  this  substance  in  100  parts  of  the  plasma 
or  serum,  respectively,  on  one  side  and  in  100  parts  of  the  blood  on 
the  other.  If  we  represent  the  amount  of  this  substance  in  the 
plasma  by  f  and  in  the  blood  by  J,  then  the  amount  of  x  in  the 

plasma  from  100  parts  of  blood  is  a;  = '—. 

Such  a  substance,  which  occurs  only  in  the  plasma,  is  fibrin 
according  to  Hoppe-Sbyler,'  sodium  according  to  Bunge^  (in 
certain  kinds  of  blood),  and  sugar  according  to  Otto,'  The 
experimenters  just  named  have  tried  to  determine  the  amount  of 
the  plasma  and  blood-corpnscles,  respectively,  in  different  kinds  of 
blood,  starting  from  the  above-mentioned  substances. 

Another  method,  suggested  by  Hoppe-Seyler,^  is  to  determine 
the  total  amount  of  hemoglobin  and  proteids  in  a  portion  of  blood, 
and  on  the  other  hand  the  amount  of  haemoglobin  and  proteids  in 
the  blood-corpuscles  (from  an  equal  portion  of  the  same  blood), 
which  have  been  sufficiently  washed  with  common-salt  solution  by 
centrifugal  force.  The  figures  obtained  as  a  difference  between 
these  two  determinations  correspond  to  the  amount  of  proteids 
which  was  contained  in  the  serum  of  the  first  portion  of  blood.  If 
we  now  determine  the  proteids  in  a  special  portion  of  serum  of  the 
same  blood,  then  the  amount  of  serum  in  the  blood  is  easily  deter- 
mined. The  usefulness  of  this  method  has  been  confirmed  by 
BuNGE  by  the  control  experiments  with  the  sodium  determinations. 
If  the  amount  of  serum  and  blood-corpuscles  in  the  blood  is  known, 
and  we  then  determine  the  amount  of  the  different  blood-constit- 
uents in  the  blood-serum  on  one  side  and  of  the  total  blood  on  the 
other,  the  distribution  of  these  different  blood-constituents  in  the 
two  chief  components  of  the  blood,  plasma,  and  blood-corpuscles 
may  be  ascertained.  According  to  the  just-mentioned  procedure, 
the  following  analyses  of  pig's  blood  and  ox's  blood  have  been  made 
by  BuNGE.  The  analyses  of  human  blood  have  been  made  by 
C.  Schmidt  ^  according  to  another  method,  which  perhaps  have 
given  rather  too  high  results  for  the  weight  of  the  blood-corpuscles. 
All  figures  represent  parts  in  1000  parts  of  blood. 

'  Handb.  d.  physiol.  und  pathol.  chem.  Analyse,  6.  Aufl.,  S.  417. 

2  Zeitschr.  f.  Biologie,  Bd.  12. 

3  Pfliiger's  Archiv,  Bd.  35,  S.  480-482. 

■»  See  Handb.  d.  physiol.  und  pathol.  chem.  Analyse,  6,  Aufl. 
'  Cited  and  partly  recalculated  from  v.  Gorup-Besanez,  Lehrb.  der  physioL 
Chem.,  4.  Aufl.,  S.  345. 


QVAXTITATIYE  COMPOSITION  OF  THE  BLOOD.         167 


Water 

Solids 

Haemoglobiu  and  ) 

Proteid  j  — 

Remaining  ore.  bodies. 

Inorganic  bodies 

K,0 

Na,0 

CaO 

MpO 

Fe,0, 

CI 

P,0.  


Pig's  Blood. 


Ox's  Blood. 


Blood-  Blood- 

cor-  cor- 
puscles! oerum  puscles 
436.8       563.2       318.7 


276.100,  517.900    191.200 
160.7001     45.300    127.500 


151.600 

5.200 
3.900 
2.421 


0.069 


0.657 
0.903 


38.100 

2.800 
4.300 
0.154 
2.406 
0.072 
0.021 
0.006 
2.034 
0.106 


2.400 
1.500 
0.238 
0.667 


0.005 


0.521 
0.224 


Serum 

681.3 


622.200 
59.100 

49.900 

3.800 
5.400 
0.173 
2.964 
0.070 
0.031 
O.0O7 
2.532 
0.181 


Human  Blood. 


Man's 


Blood- 
cor- 
puscles 
513.02 


349.690 
163.3.S0 

159.590 

3.740 
1.586 
0.241 


0.89S 

o.g;..- 


Serum 
486.98 


Woman's. 


Blood- 

puscles;  Serum 
396.24     603.76 


4.39.020    272.560 
47.960    123.680 


43.820 

4.140 
0.153 
1.661 


1.722 

0.071 


120.130 

3.550 
1.412 
0.648 


0..362 

0.643 


5.51.990 
51.770 

46.700 

5.070 
0.200 
1.91ft 


0.144 
2.202 


Hoppe-Setler,  Sacharjix/  and  Otto'  found  584.9-693.5 
p.  m.  plasma  and  -llo.  1-300.5  p.  m.  blood-corpuscles  in  horse's 
blood.  Buxge'  found,  on  the  contrary,  in  an  analysis  468. 5  p.  m, 
serum  and  531.5  p.  m.  blood-corpuscles — more  bloo,d-corpuscles, 
therefore,  than  serum.  For  human  blood  Arronet*  has  found 
4TS.S  p.  m.  blood-corpuscles  and  5'21.2  p.  m.  serum  (in  defibri- 
nated  blood)  as  an  average  of  nine  determinations.  Schxeider  * 
found  349.6  and  650.4  p.  m.  respectively  in  women. 

The  relationship  between  blood-corpuscles  and  plasma  varies;  in 
the  blood  of  men  it  is  about  50^  of  the  weight  of  the  blood,  while  in 
women  it  is  somewhat  more.  The  quantity  of  plasma  in  animals  is 
often  greater,  and  in  certain  cases  it  may  indeed  be  two  thirds  of  the 
weight  of  the  blood.  The  relationship  between  the  corpuscular 
elements  and  the  j^lasma  may  undergo  marked  fluctuation.  L.  and 
M.  Bleibtreu  found  in  10  experiments  with  defibrinated  horse- 
blood  that  the  relative  volume  of  form-elements  varied  between 
261.4  and  409.5  p.  m.  The  relative  volume  of  blood  liquid  to  the 
corpuscular  elements  varies  according  to  the  manner  in  which  the 
blood  is  drawn  from  the  animal.  L.  and  M.  Bleibtreu®  have 
found  that  the  blood  from  a  killed  animal  is  regularly  richer  in 


'■  Hnppe-Seyier's  Physiol.  Chem.,  1877-1881,  S.  447. 

*  Pflilgers  Archiv,  Bd.  35. 

M.  c. 

♦Maly's  Jaliresber.,  Bd.  17,  S.  139. 

»  Centralid.  f.  Physiol.,  Bd.  5,  S.  362. 

«L.  c. 


168  THE  BLOOD. 

corpuscles  than  blood  taken  from  the  veins.  Water  occurs  in  the 
greatest  amount  in  the  plasma  or  serum,  which  latter  ordinarily 
contains  at  least  y^-g-  water,  while  the  blood-corpuscles  contains  only 
a  little  more  than  \  or  about  f  water.  Iron  probably  occurs  only 
in  the  blood-corpuscles.  Chlorine  and  sodium  prevail  in  the 
plasma,  while  potassium  and  phosphoric  acid  prevail  in  the  blood- 
corpuscles.  In  a  few  varieties  of  blood  (pig's  and  horse's  blood) 
the  sodiam  is  found  exclusively  in  the  plasma  or  serum,  the  potas- 
sium prevailing  in  the  blood-corpuscles  (Bujstge  ').  In  dog's  and 
ox's  blood  the  blood-corpuscles  are,  however,  richer  in  sodium  than 
in  potassium  (Bunge).  In  man  the  potassium  exists  in  large 
quantities  in  the  blood-corpuscles  and  only  in  very  small  quantities 
in  the  plasma  (C.  Schmidt,^  Wanach').  The  alkaline  earths 
occur  chiefly  in  the  plasma.  Manganese  has  also  been  found  in  the 
blood,  as  well  as  traces  of  lithium,  copper,  lead,  and  silver.  The 
blood  as  a  whole  contains  in  ordinary  cases  770-820  p.  m.  water, 
with  180-230  p.  m.  solids;  of  these  173-220  p.  m.  are  organic  and 
6-10  p.  m.  inorganic.  The  organic  consist,  deducting  6-12  j).  m. 
extractive  bodies,  of  proteids  and  hsemoglobin.  The  amount  of 
this  last-mentioned  body  in  human  blood  is  about  130-150  p.  m. 
The  quantity  of  haemoglobin  in  dog's  blood  is  about  the  same ;  and 
Bltnge  found  114  p.  m.  hsemoglobin  in  pig-blood  and  89.4  p.  m.  in 
ox-blood. 

The  amount  of  sugar  in  the  blood  is  on  an  average  1-1.5  p.  m. 
The  quantity  of  urea,  which  varies  between  0.2  and  1.5  p.  m.,  is 
greater  after  partaking  of  food  than  during  fasting  (Grehant  and 
QuiNQUAUD,*  ScHONDORFF^).  The  quantity  of  uric  acid  may  be 
0.1  p.  m.  in  bird's  blood  (v.  Schroeder^).  Lactic  acid  was  first 
found  in  human  blood  by  Salomon  and  then  by  Gaglio,  Bbr- 
linerblau  and  Irisawa."^  The  quantity  of  lactic  acid  may  vary 
considerably.     Berlinerblau  found  0.71  p.  m.  as  maximum. 

1  L.  c. 

2L.  c. 

2  Maly's  Jahresber.,  Bd.  18,  S.  88. 

*  Journal   de  I'anatomie  et  de  la  physiol.,   Tome  20,  and  Compt.    rend., 
Tome  98. 

^  Pflilger's  Arch.,  Bd.  54. 

«  Ludwig's  Festschrift,  1887,  p.  89. 

'  Zeitschr.  f.  physiol.  Chem.,  Bd.  17,  which  also  gives  the  older  literature. 


BLOOD  IN  DIFFERENT    VASCULAR  REGIONS.  169 


The  Composition  of  the  Blood  in  Different  Vascular  Regions  and 
under  Different  Physiological  Conditions. 

Arterial  and  Venous  Blood.  The  most  striking  difference 
between  these  two  kinds  of  blood  is  the  variation  in  color  caused  by 
their  containing  different  amounts  of  gas  and  different  amounts  of 
oxyhfemoglobin  and  haemoglobin.  The  arterial  blood  is  light  red; 
the  venous  blood  is  dark  red,  dichroitic,  greenish  by  transmitted 
light  through  thin  layers.  The  arterial  coagulates  more  quickly 
than  the  venous  blood.  The  latter,  on  account  of  the  transudation 
which  takes  place  in  the  capillaries,  is  somewhat  poorer  in  water 
but  richer  in  blood-corpuscles  and  hgemoglobin  than  the  arterial 
blood,  but  this  is  denied  by  modern  investigators.  According  to 
Kruger  *  and  his  pupils  the  quantity  of  dry  residue  and  haemo- 
globin in  blood  from  the  carotid  artery  and  from  the  jugular  vein 
(in  cats)  are  the  same.  Koiimanx  and  Muhsam  '  could  not  detect 
any  difference  in  the  quantity  of  fat  in  arterial  and  venous  blood. 

Blood  from  the  Portal  Vein  and  the  Hepatic  Vein.  The  blood 
of  the  hepatic  vein  is  poorer  in  ordinary  red  blood-corpuscles  but 
richer  in  white  and  so-called  young  red  blood-corpuscles.  A  few 
investigators  have  concluded  from  this  that  a  formation  of  red 
blood-corpuscles  takes  place  in  the  liver,  while  others  claim  that  a 
destruction  takes  place. 

In  consequence  of  the  small  quantities  of  bile  and  lymph  found 
relatively  to  the  large  quantity  of  blood  circulating  through  the 
liver  in  a  given  time,  we  can  hardly  exj)ect  to  detect  a  positive 
difference  in  the  composition  between  the  blood  of  the  portal  and 
hepatic  veins  by  chemical  analysis.  The  statements  in  regard  to 
such  a  difference  are  in  fact  contradictory.  For  example,  Dros- 
DOFF  '  has  found  more  haemoglobin  in  the  hepatic  than  in  the  portal 
vein,  while  Otto*  found  less.  Kruger  ^  finds  that  the  quantity  of 
haemoglobin,  as  well  as  the  solids,  in  the  blood  from  the  vessels  pass- 
ing to  and  from  the  liver  is  different,  but  a  constant  relationship 
cannot  be  determined.     The  disputed  question  as  to  the  varying 

1  Zeitsclir.  f.  Biologie,  Bd.  26. 
.  *  Pflilger's  Arcliiv,  Bd.  46. 
^  Zeitschr.  f.  physiol.  Cliem. ,  Bd.  1. 

*  Christiania  Videnskabs.  Selskabs  Forhandlinger,  1886,  No.  11.    See  Maly's 
Jaliresber.,  Bd.  17,  S.  134. 

«  Zeitschr.  f.  Biologie,  Bd.  26. 


170  THE  BLOOD. 

quantities  of  sngar  in  the  portal  and  hepatic  veins  will  be  discussed 
in  a  following  chapter  (see  Chapter  VIII,  on  the  formation  of  sugar 
in  the  liver).  After  a  meal  rich  in  carbohydrates  the  blood  of  the 
portal  vein  not  only  becomes  richer  in  dextrose,  but  may  contain 
also  dextrin  and  other  carbohydrates  (v.  Merii^g,'  Otto').  The 
amount  of  urea  in  the  blood  from  the  hepatic  vein  is  greater  than 
in  other  blood  (Geehant  and  Quii^quaud  '). 

Blood  of  the  Splenic  Vein  is  decidedly  richer  in  leucocytes  than 
the  blood  from  the  splenic  artery.  The  red  blood-corpuscles  of  the 
blood  from  the  splenic  vein  are  smaller  than  the  ordinary,  less  flat- 
tened, and  show  a  greater  resistance  to  water.  The  blood  from  the 
splenic  vein  is  also  claimed  to  be  richer  in  water,  fibrin,  and 
albumin  than  the  ordinary  venous  blood  (Beclard^).  According 
to  V.  MiDDEisTDORFF,^  it  is  richer  in  haemoglobin  than  arterial  blood. 
Kruger  *  and  his  pupils  have  found  that  the  blood  from  the  vena 
lienalis  is  generally  richer  in  hsemogiobin  and  solids  than  arterial 
blood;  still  the  contrary  is  often  found.  The  blood  from  the 
splenic  vein  coagulates  slowly. 

The  Blood  from  the  Veins  of  the  Glands.  The  blood  circulates 
with  greater  rapidity  through  a  gland  during  activity  (secretion) 
than  when  at  rest,  and  the  outflowing  venous  blood  has  therefore 
during  activity  a  lighter  red  color  and  a  greater  amount  of  oxygen. 
Because  of  the  secretion  the  venous  blood  also  becomes  somewhat 
poorer  in  water  and  richer  in  solids. 

The  blood  from  the  Muscular  Veins  shows  an  opposite  behavior, 
for  during  activity  it  is  darker  and  more  venous  in  its  properties 
because  of  the  increased  absorption  of  oxygen  by  the  muscles  and 
still  greater  production  of  carbon  dioxide  than  when  at  rest. 

Menstrual  Blood  has,  according  to  an  old  statement,  not  the 
power  of  coagulating.  This  statement  is  nevertheless  false,  and  the 
apparent  uncoagulability  depends  in  part  on  the  womb  and  the 
vagina  retaining  the  blood-clot,  so  that  only  fluid  cruor  is  at  times 
eliminated,  and  in  part  on  a  contamination  with  vaginal  mucus 
which  disturbs  the  coagulation. 

'  Du  Bois-Reymond's  Archiv,  1887,  S.  412  and  431. 
^  See  note  4,  page  169. 

3  Journal  d.  rauatomie  et  de  la  physiol.,  Tome  20,  and  Compt.  rend.,  Tome 
98. 

■*  Arcli.  generale  de  medecine,  Tome  18. 

5  Cit.  from  Centralbl.  f.  Physiol.,  Bd.  2,  S.  753. 

«  Zeitschr.  f.  Biologie,  Bd.  26. 


BLOOD  AT  DIFFEREXT  PERIODS   OF  LIFE.  171 

Hie  Blood  of  the  Two  Sexes.  "Woman's  blood  coagnlates  some- 
what more  qnickh',  has  a  lower  specific  gravity,  a  greater  amount 
of  water,  and  a  smaller  quantity  of  solids  than  the  blood  of  man. 
The  amount  of  blood-corpuscles  and  haemoglobin  is  somewhat 
smaller  in  woman's  blood.  The  amount  of  haemoglobin  is,  accord- 
ing to  Otto,  146  p.  m.  for  man's  blood  and  133  p.  m.  for  woman's. 

During  pregnancy  Xasse  '  has  observed  a  decrease  in  the 
specific  gravity,  with  an  increase  in  the  amount  of  water  until  the 
end  of  the  eighth  month.  From  then  the  specific  gravity  increases, 
and  at  delivery  it  is  normal  again.  The  amount  of  fibrin  is  some- 
what increased  (Becquerel  and  Eodier,^  Nasse).  The  number 
of  blood-corpuscles  seems  to  decrease.  In  regard  to  the  amount  of 
hfemoglobiu  the  statements  are  somewhat  contradictory.  Cohx- 
STEix  '  found  the  number  of  red  corpuscles  diminished  in  the  blood 
of  pregnant  sheep  as  compared  to  non-pregnant,  but  the  red  cor- 
puscles were  larger,  and  the  quantity  of  hfemoglobin  in  the  blood 
was  greater  in  the  first  case. 

Tlie  Blood  at  Different  Periods  of  Life.  Foetal  blood  is  strik- 
ingly poorer  in  blood- corpuscles  and  haemoglobin  than  the  blood  of 
the  adult.  The  foetal  blood  at  the  moment  of  birth  has,  according: 
to  ScHERREXZiss,*  a  lower  specific  gravity,  a  markedly  lower 
amount  of  haemoglobin,  and  a  little  less  fibrin,  but  a  greater  amount 
of  mineral  bodies,  especially  proportionally  more  sodium  (but  less 
potassium)  than  the  blood  of  adults.  A  few  hours  after  birth  the 
blood  of  the  child  has  the  same  or  greater  quantity  of  haemoglobin 
than  the  blood  of  the  mother  (Cohxsteix,  Zuxtz,°  Otto').  The 
quantity  of  hemoglobin  and  blood-corpuscles  quickly  increases  after 
birth;  still  they  do  not  both  increase  at  the  same  rate,  as  the 
amount  of  haemoglobin  increases  much  faster.  Two  or  three  days 
after  birth  the  haemoglobin  reaches  a  maximum  (20-21^),  which  is 
greater  than  at  any  other  period  of  life.  This  is  the  cause  of  the 
great  abundance  of  solids  in  the  blood  of  new-born  infants  as 
observed  by  several  investigators.  The  quantity  of  hemoglobin  and 
blood-corpuscles   sinks  gradually  from    this    first   maximum  to  a 

'  Maly's  Jahresber.,  Bd.  7,  S.  129. 

2  Traite  de  chin.ie  patLol.     Paris,  1854.     P.  59. 

»  Pfluger's  Arcliiv,  Bd.  34,  S,  233. 

*  Malv's  Jahresber.,  Bd.  18. 

5  Pfluger's  Arch.,  Bd.  34,  S.  173. 

*  Maly's  Jahresber.,  Bdd.  15  and  17. 


172  THE  BLOOD. 

minimum  of  about  llfo  lisemoglobin,  wliicli  minimum  appears  in 
linman  beings  between  the  fourth  and  eighth  years.  The  quantity 
of  haemoglobin  then  increases  again  until  about  the  twentieth  year, 
when  a  second  maximum  of  13<7-15^  is  reached.  The  hemoglobin 
remains  at  this  point  only  towards  the  forty-fifth  year,  and  then 
gradually  and  slowly  decreases  (Leichtenstern,^  Otto  °).  Accord- 
ing to  older  statements,  the  blood  at  old  age  is  poorer  in  blood- 
corpuscles  and  albuminous  bodies  but  richer  in  water  and  salts. 

TJie  Influence  of  Food  on  the  Blood.  In  complete  starvation  no 
decrease  in  the  amount  of  solid  blood  constituents  is  found  to  take 
place  (Panum  '  and  others).  The  amount  of  hsemoglobin  is  a  little 
increased  (SuBBOTiiq",'  Otto),  and  also  the  number  of  red  blood- 
corpuscles  increases  (Worm  Muller,'  Buntzen''),  which  probably 
depends  on  the  fact  that  the  blood-corpuscles  are  not  so  quickly 
transformed  as  the  serum.  As  after-effect  the  inanition  causes  an 
anaemic  condition. 

After  a  rich  meal  the  relative  number  of  blood-corpuscles, 
especially  after  secretion  of  digestive  juices  or  absorption  of  nutri- 
tive liquids,  may  be  increased  or  diminished  (BuifTZEsr,  Lbichten- 
STERisr).  The  number  of  colorless  blood-corpuscles  may  be  increased 
to  such  an  extent,  after  a  diet  rich  in  proteids,  that  a  true  digestion 
leucocytosis  appears  (Hofmeister  and  Pohl').  After  a  diet  rich 
in  fat  the  plasma  becomes,  even  after  a  short  time,  more  or  less 
milky-white,  like  an  emulsion.  The  constitution  of  the  food  acts 
essentially  on  the  amount  of  lisemoglobin  in  the  blood.  The  blood 
of  herbivora  is  generally  poorer  in  haemoglobin  than  that  from 
carnivora,  and  Subbotin  has  observed  in  dogs  after  a  partial  feed- 
ing with  food  rich  in  carbohydrates  that  the  amount  of  lisemoglobin 
sank  from  the  physiological  average  of  137.5  p.  m.  to  103.2-93.7 
p.  m.  According  to  Leichtensterjst  a  gradual  increase  in  the 
amount  of  haemoglobin  is  found  to  take  place  in  the  blood  of  human 
beings  on  enriching  the  food,  and  according  to  the  same  investigator 

^  Untersucli.   ilber   den   Hamoglobingelialt   des   Blutes   im  gesunden   und 
kranken  Zustande.     Leipzig,  1878. 
'  Maly's  Jahresber. ,  Bd.  17. 

3  Virchow's  Arch.,  Bd.  29. 

4  Zeitschr.  f.  Biologie,  Bd.  7. 

^  Transfusion  und  Plethora.     Christiania,  1875. 

^  Om  Ernaeringens  og  Blodtabets  Indflydelse  pa  Blodet.  Kjobenhavn,  1879. 
See  also  Maly's  Jahresber.,  Bd.  9. 

'  Arch.  f.  exp.  Path,  und  Pharm.,  Bd.  25. 


BLOOD    UNDER  ABNORMAL    CONDITIONS.  173 

the  blood  of  lean  persons  is  generally  somewhat  richer  in  haemo- 
globin than  blood  from  fat  ones  of  the  same  age.  The  addition  of 
iron  salts  to  the  food  greatly  influences  the  number  of  blood - 
corpuscles  and  especially  the  amount  of  haemoglobin  they  contain. 
The  action  of  the  iron  salts  is  obscure.  According  to  Bunge  ' 
they  probably  combine  with  the  sulphuretted  hydrogen  of  the 
intestinal  canal  and  thereby  prevent  the  iron,  associated  in  the 
food  as  protein  combination,  from  being  eliminated  as  iron  sul- 
phide. 

The  Composition  of  the  Blood  under  Abnormal  Conditions  may 
be  changed  either  by  the  appearance  of  a  foreign  substance  or  by 
the  quantities  of  any  one  or  more  of  the  blood  constituents  being 
abnormally  increased  or  diminished.  Changes  of  this  last  kind 
occur  frequently. 

An  increase  in  the  number  of  red  corpuscles^  a  true  "  plethora 
POLYCYTHEMIC  A,"  takes  place  after  transfusion  of  blood  of  the 
same  species  of  animal.  According  to  the  observations  of  Panum^ 
and  "Worm  Muller,'  the  blood-liquid  is  quickly  eliminated  and 
transformed  in  this  case, — the  water  being  eliminated  principally 
by  the  kidneys,  and  the  albumin  burned  into  urea,  etc., — while  the 
blood  -  corpuscles  are  preserved  longer  and  cause  a  "poly- 
cythemia." A  relative  increase  in  the  number  of  red  corpuscles 
is  found  after  abundant  transudations  from  the  blood,  as  in  cholera 
and  heart-failure,  with  considerable  accumulation. 

A  decrease  in  the  numher  of  red  corjniscles  occurs  in  anaemia 
from  different  causes.  Very  excessive  hemorrhage  causes  an  acute 
ansemia  or  more  correctly  oligemia.  Even  during  the  hemorrhage 
the  remaining  blood  becomes  richer  in  water  by  diminished  secretion 
and  excretion,  as  also  by  an  abundant  absorption  of  parenchymous 
fluid  somewhat  poorer  in  proteids  and  strikingly  poorer  in  red 
blood-corpuscles.  The  oligaemia  passes  soon  into  a  hydraemia. 
The  amount  of  proteid  then  gradually  increases  again;  but  the 
re-formation  of  the  red  blood-corpuscles  is  slower,  and  after  the 
hydremia  follows  also  an  oligocythemia.  After  a  little  time  the 
number  of  blood-corpuscles  rises  to  normal;  but  the  re-formation  of 
haemoglobin  does  not  keep  pace  with  the  re-formation  of  the  cor- 
puscles,  and  a  chlorotic  condition  may  appear.     A  considerable 

1  Zeitschr.  f.  Physiol.  Chem.,  Bd.  9. 

»  Virchow's  Arch.,  Bd.  29. 

'  Transfusion  und  Plethora.     Christiania.  1875. 


174  THE  BLOOD. 

decrease  in  the  number  of  red  corpuscles  occurs  also  in  chronic 
anaemia  and  chlorosis;  still  in  such  cases  an  essential  decrease  in  the 
amount  of  haemoglobin  occurs  without  an  essential  decrease  in  the 
number  of  blocd-corpnscles.  The  decrease  in  the  amount  of 
haemoglobin  is  more  characteristic  of  chlorosis  than  a  decrease  in  the 
number  of  red  corpuscles. 

K  very  considerable  decrease  in  the  number  of  red  corpuscles 
(300,000-400,000  in  1  c.mm.)  and  diminution  in  the  amount 
of  haemoglobin  (i-yV)  occurs  in  pernicious  anaemia  (Hatem, 
Laachb^).  On  the  contrary,  the  individual  red  corpuscles  are 
larger  and  richer  in  hsemoglobin  than  they  ordinarily  are,  and  the 
number  stands  in  an  inverse  relationship  to  the  amount  of  haemo- 
globin (Hatem).  Besides  this  the  red  corpuscles  often,  but  not 
always,  show  in  pernicious  anaemia  remarkable  and  extraordinary 
irregularities  of  form  and  size,  which  Quikcke  "^  has  termed  jt?otH- 
locytosis. 

The  ComposUion  of  the  Red  Corpuscles.  Irrespective  of  the 
changes  in  the  amount  of  hemoglobin,  as  just  mentioned,  the  com- 
position of  the  blood-corpuscles  may  be  changed  in  other  ways.  By 
abundant  transudations,  as  in  cholera,  the  blood-corpuscles  may  give 
up  water,  potassium,  and  phosphoric  acid  to  the  concentrated 
plasma  and  become  correspondingly  richer  in  organic  substances 
(C.  Schmidt^).  By  a  few  other  transudation  processes,  as  in 
dysentery  and  dropsy  with  albuminuria,  a  considerable  amount  of 
proteid  passes  from  the  blood;  the  plasma  becomes  richer  in  water, 
and  the  blood-corpuscles  take  up  water  and  so  become  poorer  in 
organic  substance  (C.  Schmidt). 

The  number  of  leucocytes  may,  as  above  mentioned,  increase 
considerably  under  physiological  conditions,  such  as  after  a  meal 
rich  in  proteids  (physiological  leucocytosis).  Under  pathological 
conditions  a  hyperleucocytosis  may  occur,  and  according  to  ViR- 
CHOW '  this  occurs  in  all  pathological  processes  in  which  the  lym- 
phatic glands  take  part,  Leucocytosis  occurs  prominently  in 
leucaemia,  which  is  characterized  by  the  very  great  abundance  of 
leucocytes  in  the  blood.  The  number  of  leucocytes  is  not  only 
absolutely  increased  in  this  disease,  but  also  in  proportion  to  the 

1  Die  Anaemie.     Christiania,  1883. 

2  Deutsch.  Arch.  f.  klin.  Med.,  Bdd.  20  and  25. 

»  Cit.  from  Hoppe-Seyler's  Physiol.  Chem.,  1877-1881. 

*  Virchow's  Gesammelte  Abhandl.  zur  wissensch.  Med.,  Bd.  3. 


QUANTITY  OF   WATER,    PliOTEIDS,    FAT,    ETC.  175 

number  of  red  blood-corpuscles,  vvliicli  is  considerably  diminished 
in  leucasmia.  The  blood  from  a  leucsemic  patient  has  a  lower 
specific  gravity  than  the  ordinary  (1.035-1.040)  and  a  lighter  color, 
as  if  it  were  mixed  with  pus.  The  reaction  is  alkaline,  but  after 
death  is  often  acid,  probably  due  to  a  decomposition  of  the  con- 
siderably increased  lecithin.  In  leucsemic  blood,  volatile  fatty 
acids,  lactic  acid,  glycero-phosphoric  acid,  large  amounts  of  xanthin 
bodies  (Salomon,'  Kossel'),  and  the  so-called  Charcot's  crystals 
(see  Chapter  XIII)  have  been  found. 

The  quantity  of  water  in  the  blood  is  increased  in  general 
dropsy,  with  or  without  kidney  disease,  in  different  forms  of 
anaemia,  in  scurvy,  and  in  febrile  diseases.  The  amount  of  water 
is  diminished  in  abundant  transudations,  by  jjowerful  laxatives,  in 
diarrhoea,  and  especially  in  cholera. 

The  amount  of  proteids  in  the  blood  may  be  relatively  increased 
(hypeealbuminosis)  in  cholera  and  after  the  action  of  laxatives. 
A  decrease  in  the  amount  of  proteids  (hypalbuminosis)  occurs 
after  direct  loss  of  proteids  from  the  blood,  as  in  hemorrhage, 
albuminuria,  dysentery,  copious  formation  of  pus,  etc.,  etc.  The 
amount  of  fihrin  is  increased  (hyperijSTOSIs)  in  inflammatory  dis- 
eases, pneumonia,  acute  muscular  rheumatism,  and  erysipelas,  in 
which  the  blood  yields  a  "  crusta  phlogistic  a  "  because  it  coagu- 
lates more  slowly.  The  statements  in  regard  to  the  occurrence  of 
a  hyperinosis  in  scurvy  and  hydrasmia  seems  to  require  further  con- 
firmation. A  decrease  in  the  amount  of  fibrin  (hypinosis)  has  not 
been  observed  with  certainty  in  any  disease. 

The  amou7it  of  fat  in  the  blood  (lip^mia)  increases,  irrespective 
of  the  increase  after  a  diet  rich  in  fat,  in  drunkards,  in  corpulent 
individuals,  after  fracture  of  the  bones,  and  also  in  diabetes.  In 
the  last-mentioned  case  the  increase  in  fat  depends,  according  to 
Hoppe-Seyler,^  upon  defective  digestion.  An  increase  in  the 
amount  of  fat  in  the  blood  has  also  been  observed  in  diseases  of 
the  liver,  Bright's  disease,  tuberculosis,  malaria,  and  cholera. 
V.  Jaksch  *  has  observed  volatile  fatty  acids  in  the  blood  (lipa- 
OiDiEMiA)  in  febrile  diseases  and  sometimes  in  diabetes. 

The  amount  of  salts  in  the  blood  is  increased  in  dropsy,  dysen- 

'  Arcli.  f.  Anat.,  Physiol,  und  wissensch.  Med.,  1876* 
«  Zeitschr.  f.  pbysiol.  Cliem.,  Bd.  7,  S.  32. 
»  Physiol.  Chem.,  1877-1881,  S.  433. 
*  Zeitschr.  f.  klin.  Med.,  Bd,  11. 


176  THE  BLOOD. 

tery,  and  in  cholera  immediately  after  the  first  violent  attack,  but 
diminishes  later  after  the  attack  in  cholera,  in  scurvy,  and  in 
inflammatory  diseases.  The  decrease  of  alkali  salts,  especially 
common  salt,  is  only  trifling,  but  in  pneumonia  the  salt  disappears 
almost  entirely  from  the  urine.  A  decrease  in  the  alkalinity  of  the 
blood  has  been  observed  in  many  cases,  as  in  fevers,  uraemia,  carbon- 
monoxide  poisoning,  diseases  of  the  liver,  leucaemia,  pernicious 
anaemia,  and  diabetes. 

The  quantity  of  glucose  is  increased  in  diabetes  (mellitgemia) . 
Hoppe-Seylee  '  found  in  one  case  9  p.  m.  glucose  in  the  blood. 
According  to  Claude  Bernakd,'  when  the  quantity  of  glucose  in 
the  blood  amounts  to  3  p.  m.  it  passes  into  the  urine.  The  quan- 
tity of  ttrea  is  augmented  in  fevers,  also  in  increased  metabolism  of 
proteids.  A  further  increase  in  the  amount  of  urea  in  the  blood 
occurs  in  retarded  micturition,  as  in  cholera  as  well  as  in  cholera 
infantum  (K.  Morner'),  and  in  affections  of  the  kidneys  and  the 
urinary  passages.  After  a  ligature  of  the  nreters  or  after  extirpation 
of  the  kidneys  of  animals  an  accumulation  of  urea  takes  place  in  the 
blood.  In  uraemia,  ammonia  may  occur  in  the  blood,  which  origi- 
nates from  a  decomposition  of  the  urea.  TJy'ic  acid  is  found 
increased  in  the  blood  in  gout  (Garrod,*  Salomon  ') ;  oxalic  acid 
was  also  found  in  the  blood  in  the  same  disease  by  G-arrod. 
According  to  v.  Jaksch  fevers  alone  do  not  lead  to  uricacidmmia. 
Uric  acid  occurs  in  relatively  large  quantities,  up  to  0.08  p.  m.,  in 
affections  of  the  kidneys,  anaemia,  and  especially  such  conditions 
which  lead  to  the  symptoms  of  dyspnoea.  Naclein  bases  occur 
sometimes  in  very  small  quantities  (v.  Jaksch). 

Among  the  foreign  bodies  which  are  found  in  the  blood  the 
following  must  be  mentioned  here:  biliary  acids  and  biliary 
PIGMENTS  (which  latter  may  occur  under  physiological  conditions 
in  a  few  varieties  of  blood)  in  iceterus;  leucint  and  tyrosin  in 
acute  atrophy  of  the  liver;  aceton  specially  in  fevers  (v.  Jaksch  "). 
In  melanaemia,  especially  after  continuous  malarial  fever,  black,  less 
often  light  brown  or  yellowish,  grains  of  pigment  occur  in  the 
blood,  which,  according  to  the  generally  received  opinion,  come 

1  Physiol.  Chem.,  S.  430. 

'  Legons  sur  le  diabete. 

»  See  Maly's  Jaliresber.,  Bd.  17,  S.  453. 

■*  Med.  Surg.  Transactions,  Vols.  31  and  87. 

'  Zeitsclir.  f.  physiol.  Chem.,  Bd.  2. 

^  Ueber  Acetonurie  und  Diaceturie.     Berlin,  1885. 


QUANTITY  OF  BLOOD.  177 

from  the  spleen.  After  poisoning  with  potassinm  chlorate,  meths- 
moglobin  is  observed  in  human  and  in  canine  blood  (Marchand  ' 
and  Cahx  ') ;  but,  on  the  contrary,  no  formation  of  methaemo- 
globin  takes  place  in  the  blood  of  rabbits  (Stokvis'  and  Kiii- 
MYSER*).  A  formation  of  methfemoglobin  may  be  caused  at 
the  expense  of  the  ha?moglobin  by  the  inhalation  of  amyl  nitrite,  as 
also  by  the  action  of  a  number  of  other  medicinal  bodies  (Hayem,* 
DiTTRiCH,'  and  others). 

Tlie  quantity  of  blood  is  indeed  somewhat  variable  in  different 
species  of  animals  and  in  different  conditions  of  the  body;  in 
general  we  consider  the  entire  quantity  of  blood  in  adults  as  about 
J^-y^j  of  the  weight  of  the  body,  and  in  new-born  infants  about  ^. 
Fat  individuals  are  relatively  poorer  in  blood  than  lean  ones. 
During  inanition  the  quantity  of  blood  decreases  less  quickly  than 
the  weight  of  the  body  (Panum  '),  and  it  may  therefore  be  also  pro- 
portionally greater  in  starving  individuals  than  in  well-fed  ones. 

By  careful  bleeding  the  quantity  of  blood  may  be  considerably 
diminished  without  any  dangerous  symptoms.  The  loss  of  blood 
to  i  of  the  normal  quantity  has  as  sequence  no  durable  sinking  of 
the  blood-pressure  in  the  arteries;  while  the  smaller  arteries  accom- 
modate themselves  to  the  small  quantities  of  blood  by  contracting 
(Worm  Muller*).  A  loss  of  blood  to  ^  of  the  quantity  reduces 
the  blood-pressure  considerably,  and  a  loss  of  -j  of  the  blood  in 
adults  is  dangerous  to  life.  The  faster  the  bleeding  the  more 
dangerous  it  is.  New-born  infants  are  very  sensitive  to  loss  of 
blood,  and  likewise  fat,  old,  and  weak  persons  cannot  stand  mnch 
loss  of  blood.     AYomen  can  stand  loss  of  blood  better  than  men. 

The  quantity  of  blood  may  be  considerably  increased  by  the 
injection  of  blood  from  the  same  species  of  animal  (Panum," 
Laxdois,'"  Worm  MuLLER,'   Ponfick").      According   to   Worm 

'  Virchow's  Archiv,  Bd.  77,  and  Arch.  f.  exp.  Path,  u.  Pharm.,  Bd.  22. 

'  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  34. 

^  Ibid.,  Bd.  21. 

■•Maly'S  Jahresber.,  Bd.  14,  S.  243. 

^  Comp.  rend.,  Tome  102. 

*  Arch,  f .  exp.  Path.  u.  Pharm. ,  Bd.  29. 
'  Virchow's  Arch.,  Bd.  29. 

*  Transfusion  und  Plethora.     Christiania,  1875. 

9  Nord.  med.  Ark.,  Bd.  7  ;  Virchow's  Arch.,  Bd.  63. 

'"  Centralbl.  f.  d.  med.  Wissensch.,  1875,  and  Die  Transfusion  des  Blutes. 
Leipzis;,  1875. 

"  Virchow's  Arch.,  Bd.  63. 


178  THE  BLOOD. 

MuLLEE  the  normal  quantity  of  blood  may  indeed  be  increased  to 
83^  -without  producing  any  abnormal  conditions  or  lasting  high 
blood-jDressure.  An  increase  of  the  quantity  of  blood  to  150^  may 
be  directly  dangerous  to  life  (Wokm  Muller).  If  the  quantity  of 
blood  of  an  animal  is  increased  by  transfusion  with  blood  of  the 
same  kind  of  animal,  an  abandant  formation  of  lymph  takes  place. 
The  water  in  excess  is  eliminated  by  the  urine;  and  as  the  proteid 
of  the  blood-serum  is  quickly  decomposed,  while  the  red  blood- 
corpuscles  are  destroyed  much  more  slowly  (Tschirjew,^  Forster,^ 
Paistum,^  Worm  Muller''),  a  polycythsemia  is  gradually  produced. 

If  blood  of  another  kind  is  transfused,  then  under  certain  con- 
ditions, according  to  the  quantity  of  blood  introduced,  more  or  less 
menacing  symptoms  appear.  These  appear,  for  instance,  when  the 
blood-corpnscles  of  the  receiver  are  dissolved  easily  by  the  serum  of 
the  introduced  blood,  as,  for  example,  the  blood-corpuscles  of 
rabbits  on  transfusion  with  a  different  kind  of  blood,  or  the  reverse, 
when  the  blood-corpuscles  of  the  transfused  blood  are  dissolved  by 
the  blood  of  the  receiver;  for  instance,  when  the  blood  of  a  dog  is 
transfused  with  rabbit's  or  lamb's  blood,  or  the  blood  of  a  man  with 
lamb's  blood  (Landois^).  Before  dissolving,  the  blood-corpuscles 
may  unite  in  tough  agglomerated  heaps,  which  clog  up  the  smaller 
vessels  (Laxdois).  On  the  other  hand,  the  stromata  of  the  dis- 
solved blood-corpuscles  may  also  give  rise  to  an  extensive  intra- 
vascular coagulation,  causing  death. 

The  transfusion  should  therefore  when  possible  be  made  with 
the  blood  of  the  same  kind  of  animal,  and  for  the  resuscitating 
action  of  the  blood  it  is  immaterial  whether  or  not  it  contains  the 
fibrin  or  the  mother-substance  of  the  same.  The  action  of  trans- 
fused blood  depends  on  its  blood-corpuscles,  and  therefore  defibri- 
nated  blood  acts  just  like  non-defibrinated  (Paistum,'  Landois'). 

The  property  of  blood-serum  of  a  certain  species  of  animals  of  dissolving  or 
destroying  the  blood-corpuscles  of  another  lias  been  called  the  globulicidal 
action  of  the  serum.     According  to  Daebmberg/  Btjchner,'  and  others,  this 

1  Arbeiten  aus  der  physiol.  Anstalt  zu  Leipzig,  1874,  S.  293. 
'  Zeitschr.  f.  Biologie,  Bd.  11. 

2  Virchow's  Archiv,  Bd.  29. 
4L.  c. 

5  L.  c. 

«  Sem.  medic,  1891,  No.  51.     Cit.  from  Maly's  Jahresber.,  Bd.  22. 
^  Arch.  f.  Hygiene,  Bd.  10;  Mlinchener  med.  Wochenschr.,  1892,   No.  8, 
and  Berl.  klin.  Wochenschr.,  1892,  No.  19. 


QUANTITY  OF  BLOOD.  179 

property  stands  in  certain  relationship  to  its  bactericidal  or  so-called  micro- 
bicidal  action,  and  these  two  actions,  which  have  much  in  common,  may  be 
retarded  by  heating  the  blood-serum  to  55-65°  C.  The  microbicidal  action 
is  in  part  connected  with  the  presence  of  certain  protein  bodies  acting  like 
enzymes,  called  alexins,  and  in  })art  to  certain  mineral  bodies  such  as  sodium 
chloride  and  alkali.  Somewhat  similar  conditions  are  also  necessary  for  the 
globuiicidal  action.  Makagliaso'  has  found  that  the  blood-serum  in  many 
diseases,  such  as  pnetimonia,  malaria,  typhus,  leucmaeia,  cancerous  cachexia, 
etc.,  has  a  destructive  action  on  the  red  blood-corpuscles.  He  found  the 
quantity  of  sodium  chloride  diminished  in  such  serum,  and  the  globuiicidal 
action  was  prevented  by  the  addition  of  NaCl  sufficient  to  make  the  serum, 
normal  in  salt. 

The  quantity  of  blood  in  the  different  organs  depends  essentially 
on  the  activity  of  the  same.  During  work  the  exchange  of  material 
in  an  organ  is  more  active  than  when  at  rest,  and  the  increased 
metabolism  is  connected  with  a  more  abundant  flow  of  blood. 
Although  the  total  quantity  of  blood  in  the  body  remains  constant, 
the  distribution  of  the  blood  in  the  varions  organs  may  be  different 
at  different  times.  As  a  rule,  the  quantity  of  blood  in  an  organ 
can  be  an  approximate  measure  of  the  more  or  less  active  meta- 
bolism going  on  in  the  same,  and  from  this  point  of  view  the  dis- 
tribution of  the  blood  in  the  different  organs  and  groups  of  organs 
is  of  interest.  According  to  Eaxke,^  to  whom  we  are  especially 
indebted  for  our  knowledge  of  the  relationship  of  the  activity  of  the 
organs  to  the  quantity  of  blood  contained  therein,  of  the  total 
quantity  of  blood  (in  the  rabbit)  about  ^  comes  to  the  muscles  in 
rest,  ^  to  the  heart  and  the  large  blood-vessels,  ^  to  the  liver,  and 
^  to  the  other  organs. 

1  Berl.  klin.  Wochenschr.,  1892,  Xo.  31. 

'  Die  Blutvertheilung  und  der  Thatigkeitswechsel  der  Organe.     Leipzig, 
1871. 


CHAPTEE  VII. 

CHYLE,   LYMPH,    TEANSUDATIONS   AND  EXUDATIONS. 

I.  Chyle  and  Lyinpli. 

The  lymph  is  the  mediator  in  the  exchange  of  constituents 
between  the  blood  and  tissues.  The  bodies  necessary  for  the  nutri- 
tion of  the  tissue  pass  from  the  blood  into  the  lymph,  and  the 
tissues  deliver  water,  salts,  and  products  of  metabolism  into  the 
lymph.  The  lymph  therefore  originates  partly  from  the  blood  and 
partly  from  the  tissues.  From  a  purely  theoretical  standpoint  we 
can,  according  to  Heideisthain",  differentiate  between  blood-lymph 
and  tissue-lymph  according  to  origin.  It  is  impossible  at  the 
present  time  to  completely  separate  what  one  or  the  other  source 
delivers;  but,  thanks  to  the  pioneering  investigations  of  Heidek- 
HAii<f,  we  have  means  of  exciting  a  copious  flow  from  one  or  the 
other  sources  of  lymph.  The  action  of  these  means,  Heidenhain's 
lymphagogues,  will  be  closely  studied  later. 

According  to  older  views  the  lymph  was  only  considered  as  a 
filtrate  from  the  blood-fluid.  Since  the  investigations  of  Heiden- 
HAiN  ^  and  Hamburger  ^  this  view  cannot  be  maintained.  Accord- 
ing to  these  investigators  the  lymph  is  considered  under  physiological 
conditions  in  part  as  a  product  of  the  active,  secretory  property  of 
the  cells  of  the  blood-capillaries. 

In  chemical  respect  the  lymph  is  the  same  as  plasma  and  con- 
tains qualitatively  the  same  bodies  as  this.  The  most  essential 
difference  is  of  a  quantitative  nature  and  consists  in  that  the  lymph 
is  poorer  in  proteids.  No  essential  chemical  difference  has  been 
found   between   the   lymph   and    the    chyle  of   starving   animals. 

1  Pfiuger's  Arch.,  Bd.  49. 

2  Zeitschr.  f.  Biologie,  Bd.  27,  S.  259,  and  Bd.  30,  S.  143;  see  Ziegler's  Beitr. 
z.  pathol.  Anat.,  etc.,  Bd.  14,  S.  443. 

180 


PROTEIBS  OF  CHYLE  AND  LYMPH.  181 

After  the  assimilation  of  fatty  food  the  chyle  differs  from  the 
lymjih  in  its  wealth  of  minutely  divided  fat-globules,  which  give  it 
a  milky  appearance;  hence  the  old  name  "  milk-Juice." 

Chyle  and  lymph,  like  the  plasma,  contain  seralbumin,  serglo- 
bulin,  fibrinogen,  and  fibrin -ferment.  The  two  last-mentioned 
bodies  occur  only  in  very  small  amounts;  therefore  the  chyle  and 
lymph  coagulate  slowly  (but  spontaneously)  and  yield  but  little 
fibrin.  Like  other  liquids  poor  in  fibrin-ferment,  chyle  and  lymph 
do  not  at  once  coagulate  completely,  but  repeated  coagulations  take 
place. 

The  extractive  bodies  seem  to  be  the  same  as  in  plasma. 
Glucose  is  found  in  about  the  same  quantity  as  in  the  blood-serum, 
but  in  larger  quantities  than  in  the  blood;  this  depends  on  the 
fact  that  the  blood-corpuscles  contain  no  glucose.  According  to 
EoHMAXX  and  Bial  '  lymph  contains  a  diastatic  enzyme  similar  to 
that  in  blood-plasma,  and  Lepixe '■'  has  found  that  the  chyle  of  a 
digesting  dog  has  great  glycolytic  activity.  Dastee  ^  has  studied 
the  glycolytic  activity  of  horse's  and  cow's  lymph,  and  he  finds  that 
it  is  retarded  by  the  presence  of  2  p.  m.  potassium  oxalate.  He 
could  also  detect  glycogen  in  the  cow-lymph  which  existed  in  the 
plasma  but  not  in  the  form-elements.  The  amount  of  urea  has 
been  determined  by  Wurtz^  as  0.12-0.28  p.  m.  The  mineral 
bodies  appear  to  be  the  same  as  in  plasma. 

As  form-elements  leucocytes  and  red  blood-corpuscles  are  common 
to  both  chyle  and  lymph.  When  it  has  not  left  the  villi  of  the 
intestine  chyle  contains  very  few  leucocytes,  but  in  the  vessels  on 
the  peritoneal  side  of  the  intestine  it  is  richer  in  leucocytes.  The 
greatest  quantity  of  leucocytes  is  found  in  the  chyle  between  the 
great  mesenteric  gland  and  the  cisterna  chyli.  The  chyle  is  poorer 
in  leucocytes  in  the  thoracic  duct,  probably  because  a  mixing  takes 
place  here  with  lymph  that  is  poorer  in  form-constituents  from 
other  parts  of  the  body. 

Eed  blood-corpuscles  occur  in  the  chyle  and  lymph  in  very 
small  quantities.  In  these  liquids,  which  seem  to  be  free  from 
oxygen,  the  blood-corpuscles  are  darker-colored,  and  only  after  they 
have  come  in  contact  with  the  air  do  they  have  the  light-red  color 

•  Pfliiger's  Archiv,  Bdd.  52,  53,  and  55. 
'  Compt.  rend.,  Tome  110. 
'  Arch.  d.  Physiol. ,  Ser.  5,  Tome  7. 
"•  Compt.  rend. ,  Tome  49. 


182    CHYLE,  LYMPH,  TRANSUDATIONS  AND  EXUDATIONS. 

of  oxyhaemoglobin  and  give  the  surface  of  the  fibrin-clot  a  beaatif qI 
light-red  appearance.  It  has  been  suggested  that  this  red  color 
originates  from  the  transition  forms  between  red  and  white  blood- 
corpuscles,  in  which  .blood-coloring  matters  are  first  formed  by  the 
action  of  the  oxygen. 

The  chyle  of  starving  animals  has  the  appearance  of  lymph. 
After  partaking  of  fat  or  food  rich  in  fat  it  is  milky,  and  this  is 
partly  due  to  the  presence  of  large  fat-globules,  as  in  milk,  or 
partly,  and  indeed  chiefly,  the  finely  divided  fat.  The  nature  of 
ih.&  fats  occurring  in  the  chyle  depends  on  the  variety  of  fat  in  the 
food.  The  disproportionally  greater  part  consists  of  neutral  fats, 
and  even  after  feeding  with  abundant  amounts  of  free  fatty  acids 
MuNK '  found  in  the  chyle  chiefly  neutral  fats  with  a  small 
quantity  of  fatty  acids  or  soaps. 

The  gases  of  the  chyle  have  not  been  studied,  and  it  seems  that 
the  gases  of  an  entirely  normal  human  lymph  have  not  thus  far  been 
investigated.  The  gases  from  dog-lymph  contain  only  traces  of 
oxygen  and  consist  of  37.4-53,1^  CO^  and  1.6^  N  (ArTHOR  ')  calcu- 
lated at  0°  0.  and  760  mm.  mercury.  The  chief  mass  of  the 
carbon  dioxide  of  the  lymph  seems  to  be  firmly  chemically  com- 
bined. Comparative  analyses  of  blood  and  lymph  have  shown  that 
the  lymph  contains  more  carbon  dioxide  than  arterial,  but  less  than 
venous,  blood.  The  tension  of  the  carbon  dioxide  of  lymph  is, 
according  to  Pfluger  and  Strassburg,'  smaller  than  in  venous, 
but  greater  than  in  arterial,  blood. 

The  quantitative  composition  of  the  chyle  must  naturally  be  very 
variable.  The  analyses  thus  far  made  refer  only  to  that  mixture  of 
chyle  and  lymph  which  is  obtained  from  the  thoracic  duct.  The 
specific  gravity  varies  between  1.007  and  1.043.  As  example  of 
the  composition  of  human  chyle  we  will  here  give  two  analyses. 
The  first  is  by  Owen-Eees,^  of  the  chyle  of  an  executed  person,  and 
the  second  by  Hoppe-Seyler,^  of  the  chyle  in  a  case  of  ruptare  of 
the  thoracic  duct.  In  the  latter  case  the  fibrin  had  previously 
separated.     The  results  are  in  1000  parts. 

1  Virchow's  Arch.,  Bdd.  80  and  133. 

'  Die  Gase  der  Hundelymphe.  Arbeit,  aus  d.  physiol.  Anstalt  zu  Leipzig, 
1871. 

3  Pfluger's  Arcli.,  Bd.  6,  p.  85. 

*  Cit.  from  Hoppe-Seyler,  Physiol.  Chem.,  S.  595. 

6  lUd. ,  S.  597. 


COMPOSiriON  OF  CHTLE.  183 

No.  1.         No.  2. 

Water 904.8        940.73  water 

Solids 95.3  59.28  solids 

Fibrin traces 

Albumin 70.8  36.67  albumin 

Fat 9.2  7.33  fat 

3.35  soaps 

("0.83  lecithin 

T>        ..  -ij-  tc\  Q  1.33  cliolesterin 

Remaining  organic  bodies        10.8         \  3  gg  ^,^^^^^  extractives 

[  0 .  58  water  extractives 
CT  ,,  -    .  j  6.80  soluble  salts 

*^^^^ *•*  <  0.35  insoluble  salts 

The  quantity  of  fat  is  very  variable  and  may  be  considerably 
increased  by  partaking  food  ricli  in  fats.  J.  MuNK  and  A.  Rosen- 
STEiisr '  have  investigated  the  lympli  or  chyle  obtained  from  a  lympli 
fistula  at  the  end  of  the  upper  third  of  the  leg  of  a  girl  18  years  old 
and  weighing  60  kg.,  and  the  highest  quantity  of  fat  in  the  chylous 
lymph  was  47  p.  m.  after  partaking  of  fat.  In  the  starvation  lymph 
from  the  same  patient  they  found  only  0.6-2.6  p.  m.  fat.  The 
quantity  of  soaps  was  always  small,  and  on  partaking  of  41  gm.  fat 
the  quantity  of  soajDS  was  only  about  gV  of  the  neutral  fats. 

A  great  many  analyses  of  chyle  from  animals  have  been  made^ 
and  they  chiefly  show  the  fact  that  the  chyle  is  a  liquid  with  a  very 
changeable  composition  which  stands  closely  related  to  blood-plasma, 
bnt  with  the  chief  difference  that  it  contains  more  fat  and  less 
solids.  The  reader  is  referred  to  special  works  for  these  analyses, 
as,  for  example,  to  v.  Gorup-Besanez's  "  Lehrbuch  der  physiolo- 
gischen  Chemie,"  4th  edition. 

The  compositio)i  of  the  lymph  is  also  very  changeable,  and  its 
specific  gravity  shows  about  the  same  variation  as  the  chyle.  In  the 
following  analyses,  1  and  2,  made  by  Gubler  and  Queve]S"NE,'  are 
the  results  obtained  from  lymph  from  the  upper  part  of  the  thigh 
of  a  woman  aged  39;  and  3,  made  by  v.  Scherer,^  is  an  analysis. 
of  lymph  from  the  sac-like  dilated  lymphatic  vessels  of  the  sj)er- 
matic  cord.  No.  4  was  made  by  C.  Sch]\[idt,''  the  data  being- 
obtained  from  lympli  from  the  neck  of  a  colt.  The  results  are  in 
parts  per  1000. 

1  Virchow's  Arch.,  Bd.  133. 

*  Cit.  from  Hoppe-Seyler's  Physiol.  Chem.,  S.  591. 

» Ibid.,  S.  591. 

^L.  c. 


Ibi    CHYLE,  LYMPH,  TRANSUDATIONS  AND  EXUDATIONS. 


Water 

1 
939.9 

60.1 
0.5 

42.7 
3.8 
5.7 
7.3 

2 

934.8 

65.2 

0.6 

42.8 
9.2 

4.4 

8.3 

3 
957.6 

43.4 

0.4 

34.7  1 

"  7.2 

4 
955.4 

Solids 

Fibrin 

Albumin 

44.6 
2.3 

Fat,  cholesterin,  lecithin 

Extractive  bodies 

Salts 

35.0 
7.5 

The  salts  found  by  C.  Schmidt  in  the  lymph  of  the  horse  has 

the  following  composition,  calculated  in  parts  per  1000  parts  of  the 

lymph: 

Sodium  chloride  5. 67 

Soda 1.27 

Potash 0.16 

Sulphuric  acid 0.09 

Phosphoric  acid  united  with  alkalies .  0.03 

Earthy  phosphates 0.26 

In  the  cases  investigated  by  MuifK  and  RosEXSTEiisr '  the  quan- 
tity of  solids  in  the  fasting  condition  varied  between  35.7  and  57.2 
p,  m.  This  variation  was  essentially  dependent  upon  the  extent  of 
secretion,  so  that  the  low  amount  coincides  with  a  more  active 
secretion,  and  the  reverse  in  the  other  case.  The  chief  portion  of 
the  solids  consisted  of  proteids,  and  the  relationship  between 
globulin  and  albumin  was  as  1  :  2.4  to  4.  The  mineral  bodies  in 
1000  parts  lymph  (chylous)  was:  NaCl  5.83;  Na.CO^  2.17; 
K.HPO,  0.28;  Ca3(P0J,  0.28;  Mg3(P0J,  0.09;  and  re(POJ, 
0.025. 

Under  special  conditions  the  lymph  may  be  so  rich  in  finely 
divided  fat  that  it  appears  like  chyle.  Such  lymph  has  been  inves- 
tigated by  Heksen  "^  in  a  case  of  lymph  fistula  in  a  ten-year-old 
boy,  and  by  Lang  '  in  a  case  of  lymph  fistula  in  the  left  upper  part 
of  the  thigh  of  a  girl  of  seventeen.  The  lymph  investigated  by 
HEisTSEisr  varied  in  the  quantity  of  fat,  as  an  average  of  nineteen 
analyses,  between  2.8  and  36.9  p.  m.,  while  that  investigated  by 
Lang  contained  24.8  p.  m.  of  fat. 

The  quantity  of  lymph  secreted  must  naturally  change  consider- 
ably, and  we  have  no  means  of  measuring  it.  The  greatness  of  the 
flow  of  lymph  is,  as  Heidenhain  ^  suggests,  no  measure  as  to  the 
abundance  of  supply  of  nutritive  material  to  the  organs,  and  the 
lymph-tubes  act  according  to  him  as  "  drain-tubes,"  removing  the 

1  L.  c. 

s  Pfliiger's  Arch.,  Bd.  10. 

'  Nord.  med.  Arkiv.,  Bd.  16.     See  Maly's  Jahresber.,  Bd.  4,  p.  138. 

^L.  c. 


L  TMPHAGOO  UE8.  1 85 

excess  of  fluid  from  the  lymph  fissures  as  soon  as  the  pressure  therein 
rises  to  a  certain  height.  Attempts  have  been  made  to  determine 
the  quantity  of  lymph  flowing  in  24  hours  in  the  thoracic  duct  of 
animals.  According  to  Heidenhain  the  quantity  averages  640  c.c. 
for  a  dog  weighing  10  kilos. 

Determinations  of  the  quantity  of  lymph  ia  man  have  also  been 
attempted.  Noel-Paton  '  obtained  1  c.c.  lymph  per  minute  from 
the  thoracic  duct  of  a  patient  weighing  60  kilos.  The  quantity  in 
the  34  hours  cannot  be  calculated  from  this  amount.  In  the  case 
of  MuNK  and  Eosenstein,  1134-1372  gm.  chyle  was  collected  in 
12-13  hours  after  partaking  of  food.  In  the  fasting  condition  or 
after  starving  for  18  hours  they  found  50  to  70  gm.  per  hour,  some- 
times 120  gm.  and  above,  especially  in  the  first  few  hours  after 
powerful  muscular  exercise. 

Several  circumstances  have  a  marked  influence  on  the  extent  of 
lymph  secretion.  During  starvation  less  lymph  is  secreted  than 
after  partaking  of  food.  Nasse  '^  has  observed  in  dogs  that  the 
formation  of  lym^^h  is  increased  36^  more  after  feeding  with  meat 
than  after  feeding  with  potatoes,  and  about  54^  more  than  after 
24  hours'  deprivation  of  food. 

An  increase  in  the  total  blood-pressure,  as  by  transfusion  of 
blood,  also  especially  on  preventing  the  flow  of  blood  by  means  of 
ligatures,  causes  an  increase  in  the  quantity  of  lymj^h.  According 
to  Heidenhain,'  on  the  contrary,  a  very  considerable  change  in  the 
pressure  in  the  aorta  causes  only  a  little  change  in  the  abundance 
of  the  lymph-flow.  The  quantity  of  lymph  may  be  raised  by 
powerful  active  and  passive  movements  of  the  limbs  (Lesser  '). 
Under  the  action  of  curara  an  increase  of  the  lymph-secretion  is 
observed  (Paschutin,^  Lesser),  and  the  quantity  of  solids  in  the 
lymph  is  also  increased. 

The  means  of  inciting  the  lymph-flow  are  of  special  interest. 
They  are  called  lymphagogiies,  and  according  to  IIeidenhain  they 
are  of  two  kinds.  The  lympliagogues  of  the  first  series  are  still 
unknown  bodies  which  may  be  extracted  by  water  from  the  muscles 
of  the  crab,  the  head  and  body  of  the  blood-  and  horse-leech,  the 

'  Journal  of  Physiol.,  Vol.  11. 

2  Cit.  from  Hoppe-Seyler's  Physiol.  Chem.,  S.  593. 

»L.  c. 

^  Arbeiten  aus  der  physiol.  Anstalt  zu  Leipzig,  Jahrg.  6,  S.  94. 

^  Ibid.,  Jahrg.  7,  S.  216. 


186    CHTLE,  LTMPH,  TRANSUDATIONS  AND  EXUDATIONS. 

body  of  anodons,  the  intestine  and  liver  of  dogs.  Peptone 
(Heidenhain,'  Starliistg^)  and  sometimes  egg-albumin  may  act 
as  a  lymphagogue  of  this  series.  These  bodies  when  injected  into 
the  blood  in  watery  solution  cause  an  increase  in  the  secretion  of 
lymph,  and  the  quantity  of  organic  substances  in  the  lymph  is 
increased  at  the  same  time,  while  the  amount  of  salts  remains 
unchanged.  The  blood  becomes  more  concentrated,  due  to  extrav- 
asation of  plasma,  the  remaining  plasma  less  concentrated,  that  is, 
poorer  in  proteids.  These  lymphagogues  produce  chiefly  blood- 
lymph,  and  their  action  is  not  influenced  by  any  change  in  the  blood- 
pressure.  As  further  the  composition  of  the  lymph  and  blood- 
plasma  may  be  changed  by  membrane  filtration  under  an  increased 
pressure,  in  which  the  lymph  becomes  richer  and  the  blood-plasma 
poorer  in  proteids,  still  the  increase  in  the  lymph  formation  cannot 
be  explained,  according  to  Heidenhaust,  by  the  mechanical  filtra- 
tion process.  According  to  him  the  capillary  cells  must  take  an 
active  secretory  part  in  this  secretion. 

The  lymphagogues  of  the  second  series  are  crystalline  substances, 
such  as  sugar,  urea,  sodium  chloride,  and  other  salts.  These  bodies 
when  injected  into  the  blood  cause  a  very  copious  secretion  of 
lymph,  but  thereby  the  blood  as  well  as  the  lymph  becomes  richer  in 
water  and  poorer  in  solids.  This  increase  in  quantity  of  water  in 
the  lymph  and  blood,  which  causes  an  abundant  excretion  of  urine, 
can  only  be  attributed  to  a  more  copious  supply  of  water  of  the 
tissue-elements,  and  the  lymph  secreted  under  these  circumstances 
is  not  blood-lymph  but  chiefly  tissue-lymph.  These  bodies  inciting 
the  lymph-flow  pass  from  the  blood  into  the  lymph-spaces  by 
diflusion  and  also  in  part  (at  least  in  the  case  of  sugar)  by  the 
secretory  activity  of  the  capillary  walls,  and  have  an  attraction  for 
the  tissue-water  of  the  cells,  flbres,  etc.  This  water  passes  in  part 
by  diffusion  into  the  blood  and  then  into  the  urine,  and  another  part 
flows  into  the  lymph-canals. 

Heidenhain  has  observed  that  if  the  arterial  blood-pressure  is 
reduced  to  zero  or  near  thereto,  the  lymph-current  may  nevertheless 
continue  for  one  or  two  hours,  and  he  also  found  that  a  change  in 
the  aorta-pressure  of  between  10-20  mm.  on  one  side  and  150-200 
mm.  on  the  other  had  only  little  influence  on  the  extent  of  lymph- 
flow.     These  facts,  as  also  the  action  of  the  bodies  exciting  the 

1  L.  c. 

^  Journal  of  Physiol.,  Vol.  14. 


LTMPIIAGOGUES.  187 

lymph-flow,  do  not,  according  to  Heidexhain,  agree  with  the 
ordinary  view  that  the  lymph  is  only  a  filtrate  or  dilf  usate  of  the 
blood.  According  to  this  author,  we  must  also  consider  that  the 
cells  of  the  capillary  walls  are  directly  concerned  in  a  secretory  way 
in  the  lymph-formation. 

Hamburger  '  has  arrived  at  a  similar  view,  independently  of 
Heidexhain^,  as  to  the  importance  of  the  capillary  endothelium  in 
the  lymph -formation. 

Starling  ^  has  lately  suggested  a  series  of  experiments  in  oppo- 
sition to  Heidenhaii^'s  view,  in  which  he  comes  to  the  conclnsion 
that  the  lymph-formation  is  dependent  upon  two  factors,  namely, 
the  permeability  of  the  vascular  walls  and  the  blood-pressure,  and 
he  explains  the  action  of  the  bodies  exciting  a  lymph-flow  in  a 
different  way  from  Heidexhaix.  The  recent  researches  of 
Starling  and  Leathes,'  Orlow,'  and  Cohnsteix'  on  the 
absorption  from  serous  cavities  and  on  the  formation  of  transuda- 
tions strongly  emphasize  the  importance  of  osmosis  and  filtration 
for  absorption  and  formation  of  transudations  or  lymph. 

The  lymphagogues  of  the  first  series,  according  to  Starling, 
cause  such  an  abundant  lymph-flow  in  the  liver  that  the  entire 
increase  in  the  lymph-current  is,  in  this  case,  due  to  the  formation 
of  liver-lymph.  This  lymph  is  very  rich  in  solids,  and  the  great 
concentration  of  the  lymph  discharged  under  these  conditions  is 
due  to  this  fact.  The  blood-plasma  becomes  poorer  in  solids,  partly 
due  to  the  abundant  formation  of  concentrated  liver-lymph  and 
partly  by  admixture  with  lymph  from  other  parts  of  the  body  which 
is  poor  in  solids.  The  variations  foand  by  Heidenhain  in  the 
concentration  of  the  lymph  and  blood-plasma  is,  according  to 
Starling,  no  proof  as  to  a  special  secretory  activity  of  the  capillary 
endothelium.  The  abundant  secretion  of  concentrated  liver-lymph 
cannot  be  explained  by  a  variation  in  the  blood-pressure,  and  accord- 
ing to  Starling  it  is  due  essentially  to  an  increased  permeability 
of  the  liver-capillaries.  The  action  of  these  lymphagogues  on  the 
cells  is  not,  according  to  him,  a  physiological  one,  exciting  secre- 

'  See  Hamburger,  Zeitschr.  f.  Biologie,  Bd.  27,  S.  259,  and  Bd.  30,  S.  143. 
Also  Hamburger,  Hydrops  von  mikrobiellem  Ursprung,  in  Beitr.  zur  path. 
Anat.  und  zur  allg.  Pathol. ,  Bd.  14,  S.  443. 

i"  Journal  of  Physiol.,  Vols.  16  and  17. 

3  Journ.  of  Physiol.,  Vol.  18. 

*  Pfliiger's  Arch. ,  Bd.  59. 

*  Virchow's  Arch.,  Bd.  135,  and  Pflilger's  Arch.,  Bd.  59. 


188    CHYLE,  LYMPH,  TEAN8UDATI0NS  AND  EXUDATIONS. 

tion,  but  a  pathological  and  toxic  one  which  increases  the  perme- 
ability of  the  capillary  walls. 

The  lymphagogues  of  the  second  series  act,  according  to  Star- 
ling, first  by  osmosis,  causing  an  abundant  flow  of  water  into  the 
blood  and  thereby  increasing  the  pressure  in  the  capillaries,  produc- 
ing a  stronger  filtration.  The  more  abundant  current  of  lymph  in 
the  thoracic  duct  is  caused  in  this  case  by  a  greater  pressure  in  the 
abdominal  capillaries. 

II.  Transudations  and  Exudations. 

The  serous  membranes  are  normally  kept  moistened  by  liquids 
whose  quantity  is  only  sufficient  in  a  few  instances,  as  in  the 
pericardial  cavity  and  the  subarachnoidal  space,  for  a  complete 
chemical  analysis  to  be  made  of  them.  Under  diseased  conditions 
an  abundant  transudation  may  take  place  from  the  blood  into  the 
serous  cavities,  into  the  subcutaneous  tissues,  or  under  the  epider- 
mis ;  and  in  this  way  pathological  transudations  are  formed.  Such 
true  transudations,  which  are  similar  to  lymph,  are  generally  poor 
in  form-elements  and  leucocytes,  and  yield  only  very  little  or  almost 
no  fibrin,  while  the  inflammatory  transudations,  the  so-called 
exudations,  are  generally  rich  in  leucocytes  and  yield  proportionally 
more  fibrin.  As  a  rule,  the  richer  a  transudation  is  in  leucocytes 
the  closer  it  stands  to  pus,  while  when  it  has  a  diminished  quantity 
of  leucocytes  it  is  more  nearly  like  real  transudations  or  lymph. 

It  is  ordinarily  accepted  that  filtration  is  of  the  greatest  import- 
ance in  the  formation  of  transudations  and  exudations.  The  facts 
coincide  with  this  view,  namely,  that  all  these  fiuids  contain  the 
salts  and  extractive  bodies  occurring  in  the  blood-plasma  in  about 
the  same  quantity  as  the  blood-plasma,  while  the  amount  of  proteids 
is  habitually  smaller.  While  the  different  fluids  belonging  to  this 
group  have  about  the  same  quantities  of  salts  and  extractive  bodies, 
they  differ  from  each  other  chiefly  in  containing  differing  quantities 
of  proteid  and  form-elements,  as  well  as  varying  quantities  of  trans- 
formation and  decomposition  products  of  these  latter — changed 
blood-corloring  matters,  cholesterin,  etc.,  etc. 

It  must  be  apparent  that  the  circulation  and  pressure  conditions 

must  have  an  essential  influence  on  the  quantity  and  composition 

of  the  transudations,  but  their  action  has  been  little  studied.     An 

increase  in  the  vein-pressure  causes,  according  to,  Sbis^ator,^  an 

1  Vircliow's  Arch.,  Bd.  111. 


TRANSUDATIONS  AND  EXUDATIONS.  1S9 

increase  in  the  quantity  of  transudation  and  the  quantity  of  proteid. 
contained,  while  the  amount  of  salts  does  not  markedly  change. 
Nothing  positive  is  known  in  regard  to  the  variations  in  the 
quantity  of  proteid  by  simple  arterial  hyperemia. 

The  process,  as  suggested  by  CoHiirHEiM,'  of  the  changed  perme- 
ability of  the  capillary  walls  in  disease  is  a  second  important  factor 
in  the  formation  of  transudations.  The  circumstance  that  the 
greatest  quantity  of  proteid  occurs  in  transudations  in  inflammatory 
processes,  to  which  is  also  due  the  abundant  quantity  of  form- 
elements  in  such  transudations,  has  been  explained  by  this  hypothe- 
sis. The  greater  quantity  of  proteid  in  the  transudations  in 
formative  irritation  is  in  great  part  explained  by  the  large  amount 
of  destroyed  form-elements.  The  interesting  observation  made  by 
Paijkull,'"  that  in  such  cases  in  which  an  inflammatory  irritation 
has  taken  place  the  fluid  contains  nncleoalbumin  (or  nucleo- 
proteids?),  while  these  substances  do  not  occur  in  transudations  in 
the  absence  of  inflammatory  processes,  can  be  explained  by  the 
presence  of  form-elements. 

As  the  secretory  importance  of  the  capillary  endothelium  has 
been  made  probable  by  the  investigations  of  Heidenhaij^  and 
Hambukger,  it  is  a  priori  to  be  expected  that  an  abnormal  increased 
secretorv  activity  of  the  endothelium  is  a  third  cause  of  transuda- 
tions. Certain  observations  of  Hamburger  in  a  case  of  dropsy,^ 
in  which  the  transudation  was  probably  produced  by  the  lymph- 
exciting  action  of  a  metabolic  product  formed  by  a  bacterium,  speak 
for  the  correctness  of  this  assumption.  Hamburger  therefore 
considers  the  irritation  of  the  endothelium  of  the  capillaries  by 
means  of  a  special  substance  exciting  lymph-flow  and  formed  in 
disease  as  a  third  cause  of  the  transudations.  The  question  whether 
this  substance  acts  secretory  in  Heidexhain's  sense  or  increases 
the  permeability  in  Starling's  sense  must  be  proved. 

That  the  conditions  of  the  blood-capillaries  in  the  different 
vascular  regions  have  an  effect  on  the  quantity  of  proteid  has  been 
partly  explained  by  the  varying  secretory  activity  of  the  capillary 
endothelium  (C.  Schmidt^).  For  example,  the  amount  of  proteid 
in  the  pericardial,  pleural,  and  perito?s"eal  fluids  is  con- 

'  Cohnlieim,  Vorlesungen  iiber  allg.  Path.,  2.  Aufl.,  Part  1. 

«  Upsala  Lakarefs.  Forhandl.,  Bd.  27,  and  Maly's  Jahresber.,  Bd.  22. 

'  See  Ziegler's  Beitrage,  Bd.  14. 

*  Cit.  from  Hoppe-Seyler's  Physiol.  Chem.,  p.  607. 


190    CHYLE,  LYMPH,   TRANSUDATIONS  AND  EXUDATIONS. 

siderably  greater  than  in  those  fluids  which  are  found  in  the  SUB- 
AEACHNOIDAL    SPACE,   in   the    SUBCUTA]SrEOUS    TISSUES,    or   in    the 

AQUEOUS  HUMOE,  which  are  poor  in  proteid.  Tlie  condition  of  the 
blood  also  greatly  affects  the  transudations,  for  in  hydrgemia  the 
amount  of  proteid  in  the  transudation  is  very  small.  With  the 
increase  of  the  age  of  a  transudation,  of  a  hydrocele  fluid  for 
instance,  the  quantity  of  proteid  is  increased,  probably  by  resorp- 
tion of  water,  and  indeed  exceptional  cases  may  occur  in  which  the 
amount  of  proteid,  without  any  previous  hemorrhage,  is  even 
greater  than  in  the  blood-serum. 

The  proteids  of  transudations  are  chiefly  seralbumin,  serglobulin, 
and  a  little  fibrinogen.  The  non-inflammatory  transudations  do 
not  as  a  rule  coagulate  spontaneously,  or  very  slowly.  On  the 
addition  of  blood  or  blood-serum  they  coagulate.  Inflammatory 
exudations  coagulate  spontaneously.  Paijkull  '  has  shown  that 
these  often  contain  nucleoalbumin.  Mucoid  substances,  which 
were  first  observed  by  the  author  ^  in  a  few  cases  of  ascitic  fluid, 
without  complication  with  ovarial  tumors,  seem,  according  to 
Paijkull,  to  be  regular  constituents  of  transudations.  The  rela- 
tionship between  globulin  and  seralbumin  varies  very  much  in 
different  cases,  but,  as  HoFFMAisrisr '  and  Pigeaud  ^  have  shown,  the 
variation  is  in  each  case  the  same  as  the  blood-serum  of  the  indi- 
vidual. 

The  specific  gravity  runs  rather  parallel  with  the  quantity  of 
proteid.  The  varying  specific  gravity  has  been  suggested  as  a 
means  of  differentiation  between  transudations  and  exudations  by 
EEUss,^as  the  first  often  show  a  specific  gravity  below  1015-1010, 
while  the  others  have  a  specific  gravity  of  1018  or  above.  This  rule 
holds  good  in  many  but  not  in  all  cases. 

The  gases  of  the  transudations  consist  of  carbon  dioxide  besides 
small  amounts  of  nitrogen  and  traces  of  oxygen.  The  tension  of 
the  carbon  dioxide  is  greater  in  the  transudations  than  in  the  blood. 
On  mixing  with  pus  the  amount  of  carbon  dioxide  is  decreased. 

The  extractives  are,  as  above  stated,  the  same  as  in  the  blood- 
plasma;  but  sometimes  extractive  bodies  occur,  such  as  allantoin  in 

1  L.c. 

^  Zeitschr.  f.  physiol.  chem.,  Bd.  15. 
3  Arcli.  f.  exp.  Path.  u.  Pharm.,  Bd.  16. 
*  See  Maly's  Jabresber.,  Bd.  16. 
6  Deutsch.  Arch.  f.  klin.  Med.,  Bd.  28. 


PERICARDIAL  FLUID.  191 

dropsical  fluids  (Moscatelli '),  which  have  not  been  detected  in 
the  blood.  Urea  seems  to  occur  in  very  variable  amounts.  Glucose., 
or  at  least  a  fermentable  substance  which  reduces  copper  oxide  in 
alkaline  liquids,  occurs  in  most  transudations.  Succinic  acid  has 
been  found  in  a  few  cases  in  hydrocele  fluids,  while  in  other  cases 
it  is  entirely  absent.  Leucin  and  tyrosin  have  been  found  in  trans- 
udations from  diseased  livers  and  in  pus-like  transudations  which 
have  undergone  decomposition.  Among  other  extractives  found  in 
transudations  we  must  mention  uric  acid.,  allantom.,  xantliin^ 
creatin,  inosii,  and  2^1/^'Ocatechiu. 

As  above  stated,  irrespective  of  the  varying  number  of  form- 
elements  contained  in  the  different  transudations,  the  quantity  of 
proteid  is  the  most  characteristic  chemical  distinction  in  the  com- 
position of  the  various  transudations;  therefore  a  quantitative 
analysis  is  only  of  importance  in  so  far  as  it  considers  the  quantity 
of  proteid.  On  this  account  the  following  quantitative  composition 
is  referred  to  the  chief  weight,  the  quantity  of  proteid. 

Pericardial  Fluid.  The  quantity  of  this  fluid  is  also,  under 
certain  physiological  conditions,  so  large  that  a  sufficient  quantity 
for  chemical  investigation  was  obtained  from  a  person  who  had  been 
executed.  This  fluid  is  lemon-yellow  in  color,  somewhat  sticky, 
and  yields  more  fihrin  than  other  transudations.  The  amount  of 
solids,  according  to  the  analyses  performed  by  v.  Gorup-Besanez,'' 
Wachsmuth,-'  and  Hoppe-Seyler,'  is  37.5-44.9  p.  m.,  and  the 
amount  of  proteid  is  22.8-24.7  p.  m.  The  analysis  made  by  the 
AUTHOR  of  a  fresh  pericardial  fluid  from  a  young  man  who  had  been 
executed  yielded  the  following  results,  calculated  in  1000  parts  by 
weight : 

Water 960.85 

Solids 39.15 

(Fibrin 0.31 

Proteids 28.60 -^  Globulin 5.95 

(Albumin 22.34 

Soluble  salts 8.60-|NaCl 7.28 

Insoluble  salts    0.15 

Extractive  bodies 2.00 

"  Zeitschr.  f.  physiol.  Chem.,  Bd.  13. 

'  V.  Gorup-Besanez,  Lehrbuch  d.  physiol.  Chem.,  4.  Aufl.,  S.  401. 

•  Vircbow's  Arch.,  Bd.  7. 

*  Physiol.  Chem.,  S.  605. 


1^2    CHYLE,  LTMPH,   TRANSUDATIOXS  AND  EXUDATIONS. 

!Feiexd  '  lias  found  nearly  the  same  composition  for  a  pericar- 
dial fluid  from  a  horse,  with  the  exception  that  this  liquid  was 
relatively  richer  in  globulin.  The  ordinary  statement  that  pericar- 
dial fluids  are  richer  in  fibrinogen  than  other  transudations  is  hardly 
based  on  sufficient  proof.  In  a  case  of  chylojoericardium,  which 
was  probably  due  to  the  rupture  of  a  chylus  vessel  or  caused  by  a 
capillary  exudation  of  chyle  because  of  stoppage,  Hasebroek  * 
found  in  1000  joarts  of  the  analyzed  fluid  103.61  parts  solids,  73.79 
albuminous  bodies,  10.77  fat,  3.34  cholesterin,  1.77  lecithin,  and 
9.34  salts. 

The  pleural  fluid  occurs  under  physiological  conditions  in  such 
small  quantities  that  a  chemical  analysis  of  the  same  cannot  be 
made.  Under  pathological  conditions  this  fluid  may  show  very 
variable  properties.  In  a  few  cases  it  is  nearly  serous,  in  others 
again  sero-fibrinous,  and  in  others  similar  to  pus.  There  is  a  corre- 
sponding variation  in  the  specific  gravity  and  the  j^i'operties  in 
general.  If  a  jDus-like  exudation  is  kept  closed  for  a  long  time  iu 
the  pleural  cavity,  a  more  or  less  complete  maceration  and  solution 
of  the  pus-corpuscles  is  found  to  take  place.  The  ejected  yellowish- 
brown  or  greenish  fluid  may  then  be  as  rich  in  solids  as  the  blood- 
serum;  and  an  abundant  flocculent  precipitate  of  a  nucleoalbnmin 
(the  7;ym  of  early  writers)  may  be  obtained  on  the  addition  of 
acetic  acid.  This  precipitate  is  soluble  with  difficulty  in  an  excess 
of  acetic  acid. 

Numerous  analyses,  by  many  investigators,^  of  the  quantitative 
composition  of  pleural  fluids  under  pathological  conditions  are  at 
hand.  From  these  analyses  we  learn  that  in  hydro  thorax  the 
specific  gravity  is  lower  and  the  quantity  of  ]Droteid  less  than  in 
pleuritis.  In  the  first  case  the  specific  gravity  is  generally  less  than 
1015,  and  the  quantity  of  proteid  10-30  p.  m.  In  acute  pleuritis 
the  sjDecific  gravity  is  generally  higher  than  1020,  and  the  quantity 
of  proteid  30-65  p.  m.  The  quantity  of  fibrinogen,  which  in 
hydro  thorax  is  about  0.1  p.  m.,  may  amount  to  more  than  1  p.  m. 
in  pleuritis.  In  pleurisy  with  an  abundant  gathering  of  pus  the 
specific  gravity  may  rise  even  to  1030,  according  to  the  observations 

1  Halliburton:  Text-book  of  Chem.  Physiol.,  etc.     London,  1891.     P.  347. 

*  Zeitschr.  f.  physiol.  cbem.,  Bd.  12. 

*  See  the  works  of  Mehu,  Runeberg,  F.  Hoffmann,  Reuss,  Neuenkirchen,  all 
of  which  are  cited  in  Bernheim's  yjayjer  in  Virchow's  Arch.,  Bd.  131,  S.  274. 
See  also  Paijkull,  1.  c,  and  Halliburton's  Text-book,  p.  346. 


PERITONEAL  FLUID.  193 

of  tlie  AUTHOR.  The  quantity  of  solids  is  often  60-70  p.  m.,  and 
may  be  even  more  than  90-100  p.  m.  (author).  Mucoid  sub- 
stances have  also  been  detected  in  pleural  fluids  by  Paijkull. 
Cases  of  chylous  pleurisy  are  also  known ;  in  such  a  case  Mehu  ^ 
found  17.93  p.  m.  fat  and  cliolesterin  in  the  flnid. 

The  quantity  of  peritoneal  fluid  is  very  small  under  physiological 
conditions.  The  investigations  refer  only  to  the  fluid  under 
diseased  conditions  {dropsical  or  ascitic  fluid).  The  color,  trans- 
parency, and  consistency  of  these  may  vary  greatly. 

In  cachectic  conditions  or  a  hydr^emic  condition  of  the  blood  the 
fluid  has  little  color,  is  milky,  opalescent,  watery,  does  not  coagu- 
late spontaneously,  has  a  very  low  specific  gravity,  1005-1010-1015, 
and  is  nearly  free  from  form-elements. 

The  ascitic  fluid  in  portal  stagnation,  or  generally  in  venous- 
stagnation,  has  a  low  specific  gravity  and  ordinarily  less  than  20 
p.  m.  proteid,  although  in  certain  cases  the  quantity  of  proteid  may 
rise  to  35  p.  m.  In  carcinomatous  peritonitis  it  may  have  a  cloudy, 
dirty-gray  appearance,  due  to  its  richness  in  form-elements  of 
various  kinds.  The  specific  gravity  is  then  higher,  the  quantity  of 
solids  greater,  and  it  often  coagulates  spontaneously.  In  inflamma- 
tory processes  it  is  straw-  or  lemon-yellow  in  color,  somewhat  cloudy 
or  reddish,  due  to  leucocytes  and  red  blood-corpuscles,  and  from 
great  richness  in  leucocytes  it  may  appear  more  like  pus.  It 
coagulates  spontaneously,  and  may  be  relatively  richer  in  solids.  It 
contains  regularly  30  p.  m.  or  more  proteid  (although  exceptions 
with  less  proteid  occur),  and  may  have  a  specific  gravity  of  1.030 
or  above.  By  rupture  of  a  chylous  vessel  the  dropsical  flnid  may 
be  rich  in  very  finely  emulsified  fat  (chylous  ascites).  In  such 
cases  3.86-10.30  p.  m.  fat  has  been  found  in  the  dropsical  fluid. 
(GuiJfocHET,"  Hay'),  or  even  17-13  p.  m.  fat  has  been  found  by 
MiN'KOWSKY.  By  admixture  of  this  fluid  with  the  fluid  from  art 
ovarian  cyst  it  ma}^  sometimes  contain  pseudomucin  (see  Chapter 
XIII).  We  also  have  cases  in  which  the  ascitical  fluid  contains 
mucoids  which  may  be  precipitated  by  alcohol  after  removal  of  the 
proteids  by  coagulation  at  boiling  temperature.  Such  substances, 
which  yield  a  reducible  substance  on  boiling  with  acids,  have  been 

'  Arch.  gen.  de  med. ,  1886,  Tome  3.     Cit  from  Maly's  Jaliresber.,  Bd.  16. 
"-  See  Straus,  Arcli.   de  physiol,    Tome  18.      Cit.   from  Maly's  Jahresber., 
Bd.  17. 

3  See  Maly's  Jahresber.,  Bd.  16,  S.  475. 


194    CHILE,  LYMPH,   TRANSUDATIONS  AND  EXUDATIONS. 

fonad  by  the  author  in  tuberculous  peritonitis  and  in  cirrhosis 
hepatis  syphilitica  in  men.  According  to  the  investigations  of 
Paijkull  '  these  substances  seem  to  occur  often  and  perhaps 
habitually  in  the  ascitic  fluids. 

As  the  quantity  of  proteid  in  ascitic  fluids  is  dependent  ujoon 
the  same  circumstances  as  in  other  transudations  and  exudations, 
it  is  sufficient  to  give  the  following  example  of  the  composition, 
taken  from  Beknheoi's  "  treatise.  The  results  are  expressed  in 
1000  parts  of  the  fluid: 

Max.         3Iin.  Mean. 

Cirrhosis  of  the  liver 34.5  5.6       9.69  —  21.06 

Brigbt's  disease 16.11     10.10       5.6         10.36 

Tuberculous  and  idiopathic  peritonitis ... .   55.8       18.72     30.7    — 37.95 

Carcinomatous  peritonitis 54.20     27.00     35.1    —  58.96 

Urea  has  also  been  found  in  ascitical  fluids,  sometimes  only  as  traces,  somb- 
times  in  larger  quantities  (4  p.  m.  in  albuminuria),  also  uric  acid,  aliantoin  in 
cirrhosis  of  the  liver  (Moscatelli^),  xanthin,  creatin,  cholestcrin,  and  glucose. 

Hydrocele  and  Spermatocele  Fluids.  These  fluids  differ  from 
each  other  in  various  ways.  The  hydrocele  fluids  are  generally 
colored  light  or  darker  yellow,  sometimes  brownish  with  a  shade  of 
green.  They  have  a  relatively  higher  specific  gravity,  1.016-1.026, 
with  a  variable  but  generally  higher  amount  of  solids,  an  average  of 
60  p.  m.  They  sometimes  coagulate  spontaneously,  sometimes  only 
after  the  addition  of  fibrin-ferment  or  blood.  They  contain 
leucocytes  as  chief  form-elements.  Sometimes  they  contain  smaller 
or  larger  amounts  of  clwlesterin  crystals. 

The  spermatocele  fiuids,  on  the  contrary,  are  as  a  rule  colorless, 
thin,  cloudy  like  water  mixed  with  milk.  They  sometimes  have  an 
acid  reaction.  They  have  a  lower  specific  gravity,  1.006-1.010,  a 
lower  amount  of  solids — an  average  of  about  13  p.  m., — and  do  not 
coagulate  either  spontaneously  or  after  the  addition  of  blood.  They 
are,  as  a  rule,  poor  in  proteid  and  contain  spermatozoa,  cell-detritus, 
and  fat-globules  as  form-constituents.  To  show  the  unequal  com- 
position of  these  two  kinds  of  fluids  we  will  give  the  average  results 
(calculated  in  parts  per  1000  parts  of  the  fluid)  of  17  analyses  of 
hydrocele  fluids  and  4  of  sj)ermatocele  fluids  made  by  the  author:' 

'  L.  c. 

'■^  L.  c.  As  it  was  impossible  to  derive  mean  figures  from  those  given  hj 
Bernheim,  the  author  has  given  above  the  maximum  and  minimum  of  the 
averages  given  by  him. 

^'L.  c. 

4  Upsala  Lakaref.  Forh.,  Bd.  14,  and  Maly's  Jahresber.,  Bd.  8,  S.  347. 


CEREBROSPINAL  FLUID.  195 

Hydrocele.    Spermatocele. 

Water 938.85  986.33 

Solids 61.15  18.17 

Fibrin 0.59  

Globulin 13.25  0.59 

Seralbumin 35.94  1.83 

Ether  extractive  bodies .        4.03  ) 

Soluble  salts 8.60  [■       10.76 

Insoluble  salts 0.66  ) 

In  the  hydrocele  fluid  traces  of  urea  and  a  reducing  substance  have  been 
found,  and  in  a  few  cases  also  succinic  acid  and  inosit.  A  hydrocele  fluid  may, 
according  to  Dj:villard, '  sometimes  contain  paralbumin  or  metalbumin  (?). 
Cases  of  chylous  hydrocele  are  also  known. 

Cerebro-spinal  Fluid.  This  flaid  has  heretofore  been  considered 
as  a  secretion  and  not  a  transudation.  But  as  we  now  consider  not 
only  the  lymph  as  part  secretion,  but  also  the  transudations,  such  a 
difference  between  this  flnid  and  the  others  cannot  be  maintained. 
The  cerebro-spinal  flnid  is  thin,  water-clear,  of  low  specific  gravity, 
1007-1008.  Tiie  spina  bifida  fluid  is  very  poor  in  solids,  8-10 
p.  m.,  with  only  0,19-1.6  p.  m.  proteid.  The  fluid  of  chronic 
hydrocephalus  is  somewhat  richer  in  solids  (13-19  p.  m.)  and  pro- 
teids.  According  to  Halliburton  *  tlie  proteid  of  the  cerebro- 
spinal fluid  is  a  mixture  of  glohulm  and  alhumoscs;  occasionally 
some  peptone  occurs,  and  more  rarely,  in  special  cases,  seralbumin 
appears.  An  optically  inactive,  non-fermentable,  reducing  sub- 
stance, seemmgly  pyrocatechm  (IlALLiBURTOisr),  has  been  observed 
in  this  fluid.  The  older  statement  that  the  cerebro-spinal  fluid 
differs  from  the  other  transudations  in  a  greater  wealth  of  potassium 
salts  has  not  been  conflrmed  by  recent  investigations  of  Yvojsr  °  and 
Halliburton.  According  to  Cavazzani  '  the  cerebro-spinal  fluid 
is  more  alkaline  and  richer  in  solids  in  the  morning  than  in  the 
evening. 

Aqueous  Humor.  This  fluid  is  clear,  alkaline,  and  has  a  specific 
gravity  of  1.003-1.009.  The  amount  of  solids  is  on  an  average  13 
p.  m.,  and  the  amount  of  proteids  only  0,8-1.3  p.  m.  The  proteid 
'consists  of  seralbumin  and  globulin  and  very  little  fibrinogen. 
According  to  Gruenhagen,"  it  contains  paralactic  acid.,  another 
dextrogyrate  substance,  and  a  reducing  body  which  is  not  similar 

>  Bull.  soc.  chim.,  Tome  49,  p.  617. 
^2  Halliburton's  Text-book,  pp.  355-361. 

*  Journ.  de  Pharm.  et  de  Chim.  (4  Ser.),  Tome  36, 
4  Maly's  Jahresber.,  Bd.  83,  S.  346. 

*  Pflliger's  Arch.,  Bd.  43. 


196    CHYLE,  LYMPH,   TBAN8UDATI0N8  AND  EXUDATIONS. 

to  glucose  or  dextrin.  Pautz  '  found  urea  and  sugar  in  the  aqueous 
humor  of  oxen. 

Blister-fluid.  The  content  of  blisters  caused  by  burns,  and  of 
vesicator  blisters  and  the  blisters  of  the  pemphigus  chronicus,  is 
generallj'-  a  fluid  rich  in  solids  and  proteids  (40-65  p.  m.).  This  is 
especially  true  of  the  contents  of  vesicatory  blisters,  which  also  con- 
tain a  substance  that  reduces  copper  oxide.  The  fluid  of  the 
pemphigus  is  slimy  and  alkaline  in  reaction. 

The  fluid  of  subcutaneous  oedema.  This  is,  as  a  rule,  very  poor 
in  solids,  purely  serous,  does  not  contain  fibrinogen,  and  has  a 
specific  gravity  of  1.005-1.010.  The  quantity  of  proteids  is  in 
most  cases  lower  than  10  p.  m., — according  to  HoFPMANiir  1-8 
p.  m., — and  in  serious  affections  of  the  kidneys,  generally  with, 
amyloid  degeneration,  less  than  1  p.  m.  has  been  shown  (Hoff- 
mann^). The  cedema  fluid  also  habitually  contains  urea,  1-2 
p.  m.,  and  also  a  reducing  substance. 

The  FLTJID  OF  THE  TAPEWORM  cyst  IS  related  to  tile  transudations.  It  is 
thin  and  colorless,  and  has  a  specific  gravity  of  1.005-1.015.  The  quantity  of 
solids  is  14-20  p.  m.  The  chemical  constituents  are  glucose  (3.5  p.  ni.),  inosit^ 
traces  of  urea,  creatin,  succinic  acid,  and  salts  (8.3-9.7  p,  m.).  Proteids  are 
only  found  in  traces,  and  then  only  after  an  inflammatory  irritation.  In  the 
last-mentioned  case  7  p.  m.  proteids  have  been  found  in  the  fluid. 

The  Synovial  Fluid  and  Fluid  in  Synovial  Cavities  around 
Joints,  etc.  The  synovia  is  hardly  a  transudation,  but  it  is  often 
treated  as  an  appendix  to  the  transudations. 

The  synovia  is  an  alkaline,  sticky,  fibrous,  yellowish  fluid  which 
is  cloudy,  from  the  presence  of  cell-nuclei  and  remains  of  destroyed 
cells,  but  is  sometimes  clear.  It  contains  also,  besides  proteids  and 
salts,  a  substance  similar  to  mucin  in  physical  properties.  The 
nature  of  these  mucin-like  constituents  of  physiological  synovial 
fluids  has  not  been  determined.  The  author '  has  found  a  mucin- 
like  substance  in  pathological  synovial  fluid,  but  it  was  not  true 
mucin.  It  acts  like  a  nucleoalbumin  or  a  nucleoproteid,  and  gave 
no  reducing  substance  when  boiled  with  acid.  Salkowski  *  also 
found  a  mucin-like  substance  in  a  pathological  synovial  fluid, 
which  was  neither  mucin  nor  nucleoalbumin.  He  called  the  sub 
stance  "  synovin.'''' 

1  Zeitschr.  f.  Biologie,  Bd.  31. 
^  Deutsch.  Arch.  f.  klin.  Med.,  Bd.  44. 
3  Upsala  Lalcaref.  Forhandl.,  Bd.  17. 
^  Virchow's  Arch..  Bd.  131. 


PUS.  197 

The  composition  of  synovia  is  not  constant,  but  varies  in  rest 
and  in  motion.  In  the  kst-mentioned  case  the  quantity  of  fluid  is 
less,  but  the  amount  of  the  mucin-like  body,  proteids,  and  of  the 
extractive  bodies  is  greater,  while  the  quantity  of  salts  is  diminished. 
This  may  be  seen  from  the  following  analyses  by  Frerichs.'  The 
figures  represent  parts  per  1000. 

I.  Synovia  from    II.  Synovia  from 
a  Stall-fed  Ox.        a  Field-fed  Ox. 

•Water 969.9  948.5 

Solids 30.1  51.5 

Mucin-like  body .  2.4  5.6 

Proteids  and  extractives 15.7  35.1 

Fat 0.6  0.7 

Salts 11.3  *                  9.9' 

The  synovia  of  new-born  babes  corresponds  to  that  of  resting 
animals.  The  fluid  of  the  bursse  mucosag,  as  also  the  fluid  in  the 
synovial  cavities  around  joints,  etc.,  is  similar  to  synovia  from  a 
qualitative  standpoint. 

III.  Pus. 

Pus  is  a  yellowish-gray  or  yellowish-green,  creamy  mass  of  a 
iaint  odor  and  an  unsavory,  sweetish  taste.  It  consists  of  a  fluid, 
the  pus-serum,  in  which  solid  particles,  the  pus-cells,  swim.  The 
number  of  these  cells  varies  so  considerably  that  the  pus  may  at  one 
time  be  thin  and  at  another  time  so  thick  that  it  scarcely  contains 
a  drop  of  serum.  The  specific  gravity,  therefore,  may  also  greatly 
vary,  namely,  between  1.020  and  1.040,  but  ordinarily  it  is  1.031- 
1.033.  The  reaction  of  fresh  pus  is  generally  alkaline,  but  it  may 
become  neutral  or  acid  from  a  decomposition  in  which  fatty  acids, 
glycero-phosphoric  acid,  and  also  lactic  acid  are  formed.  It  may 
become  strongly  alkaline  when  putrefaction  occurs  with  the  forma- 
tion of  ammonia. 

In  the  chemical  investigation  of  pus  the  pus-serum  and  the  pus- 
corpuscles  must  be  studied  separately. 

Pus-serum.  Pus  does  not  coagulate  spontaneously  nor  after  the 
addition  of  defibrinated  blood.  The  fluid  in  which  the  pus- 
corpuscles  are  suspended  is  not  to  be  compared  with  the  plasma,  but 
rather  with  the  serum.  The  pus-serum  is  pale  yellow,  yellowish 
green,  or  brownish  yellow,  and  has  an  alkaline  reaction.     It  con- 

1  Wagner's  Handworterbuch,  Bd.  3,  Abth.  1,  S.  463. 


198    CHTLE,  LYMPH,  TBAN8UDATI0N8  AND  EXUDATION'S. 

tains,  for  the  most  part,  tlie  same  constituents  as  the  blood-serum^ 
but  sometimes  besides  these — when,  for  instance,  the  pus  has 
remained  in  the  body  for  a  long  time — it  contains  a  nucleoalbumin 
or  nucleoproteid  which  is  precipitated  by  acetic  acid  and  soluble 
with  great  difficulty  in  an  excess  of  the  acid  {pyin  of  the  older 
authors).  This  nucleoalbumin  seems  to  be  formed  from  the  hyaline 
substance  of  the  pus-cells  by  maceration.  The  pus-serum  contains, 
moreover,  at  least  in  many  cases,  no  fibrin-ferment.  According  to 
the  analyses  of  Hoppe-Setler,'  the  pus-serum  contains  in  1000 
parts : 

I.  II. 

Water 913.7  905.65 

Solids 86  3  94.35 

Proteids 63.23  77.21 

Lecitliin 1.50  0.56 

Fat 0.26  0.29 

Cholesterin 0.53  0.87 

Alcoliol  extractives 1.52  0.73 

Water  extractives 11.53  6.92 

Inorganic  salts 7.73  7.77 

The  asli  of  pus-serum  lias  the  following  composition,  calculated  to  1000 
parts  of  the  serum  : 

I.  II. 

NaCl..    5.22  5.39 

Na2S04 0.40  0.31 

Na2HP04 0.98  0.46 

Na^COa 0.49  1.18 

Ca3(P04)2 0.49  0.31 

Mg3(P04)2 0.19  0.12 

PO4  (in  excess) .05 

The  pus-corpuscles  are  generally  thought  to  consist  in  great  part 
of  emigrated  white  blood-corpuscles  (emigration  hypothesis),  and 
their  chemical  properties  have  therefore  been  given  above.  "We 
consider  the  molecular  grains,  fat-globules,  and  red  blood-corpus- 
cles rather  as  casual  form-elements. 

The  pus-cells  may  be  separated  from  the  serum  by  centrifugal 
force,  or  by  decantation  directly  or  after  dilution  with  a  solution  of 
sodium  sulphate  in  water  (1  vol.  saturated  sodium-sulphate  solution 
and  9  vols,  water),  and  then  washed  by  this  same  solution  in  the 
same  manner  as  the  blood-corpuscles. 

The  chief  constituents  of  the  pus-corpuscles  are  albuminous 
bodies  of  which  the  largest  proportion  seems  to  be  a  nucleoproteid 
"which  is  insoluble  in  water  and  which  expands  into  a  tough,  slimy 

'  Med.  chem.  Untersuch.,  S.  490. 


PUS.  199 

mass  when  treated  witli  a  lOfo  common-salt  solution.  This  proteid 
substance,  which  is  soluble  in  alkali  but  quickly  changed  thereby, 
is  called  Eovidas's  hyaline  sulstance,  and  the  property  of  the  pus 
of  being  converted  into  a  slime-like  mass  by  a  solution  of  common 
salt  depends  on  this  substance.  Besides  this  substance  we  find  in 
the  j)us-cells  also  an  albuminous  body  which  coagulates  at  48-49°  C, 
as  well  as  serglobulin  (?),  seralbumin,  a  substance  similar  to  coagu- 
lated albumin  (Miescher),'  and  lastly  peptone  (Hofmeister).' 

"We  also  find  in  the  protoplasm  of  the  pus-cells,  besides  the  pro- 
teids,  lecithin,  cholesterin,  xanthin  bodies,  fat,  and  soaps.  Hoppe- 
Setler  has  found  cerebrin,  a  decomposition  product  of  a  protagon- 
like  substance,  in  pus  (see  Chapter  XII).  Kossel  and  Frettag  * 
have  isolated  from  pus  two  substances,  pyosUi  and  pyogenin,  which 
belong  to  the  cerebrin  group  (see  Chapter  XII).  IIoppe-Seyler* 
claims  that  glycogen  appears  only  in  the  living,  contractile  white 
blood-cells  and  not  in  the  dead  pus-corpuscles.  Salomon  *  has 
nevertheless  found  glycogen  in  pus.  The  cell-nucleus  contains 
nuclein  and  nucleoproteids. 

The  jnineral  constituents  of  the  pus-corpuscles  are  potassium, 
sodium,  calcium,  magnesium,  and  iron.  A  part  of  the  alkalies  is 
found  as  chlorides,  and  the  remainder,  as  well  as  the  other  bases, 
exists  as  phosphates. 

The  quantitative  composition  of  the  pus-cells  from  the  analyses 

of  Hoppe-Seyler  is  as  follows,  in  parts  per  1000  of  the  dried 

substance : 

I.  II. 

Proteids 137.63 ) 

Nuclein 342  57  V  685.85        673.69 

Insoluble  bodies 205.66 ) 

Lecithin )     i^qqq  75.64 

Fat \    ^^^-^"^  75.00 

Cholesterin 74.00  72.83 

Cerebrin 51.99)  mo  S4^ 

Extractive  bodies 44.33  |  ^"'^•°* 

MINERAL   SUBSTANCES   IN    1000   PARTS   OF   THE   DRIED   SUBSTANCE. 

NaCl 4.35 

Ca3(P04), 2.05 

Mg3(  PU,  )2 1.13 

FeP04 1 .06 

PO4 9.16 

Na 0.68 

K traces  (?) 

'  Hoppe-Seyler's  Med.  chem.  Untersuch.,  S.  441. 

^  Zeitschr.  f.  physiol.  Chem. ,  Bd.  4. 
^  Ihid.,  Bd.  17,  S.  452. 

4  Physiol.  Chem.,  S.  790. 

5  Deutsch.  med.  Wochenschr.,  1877,  No.  8. 


200    CHYLE,  LYMPH,   TRANSUDATIONS  AND  EXUDATIONS. 

MiESCHER  has  obtained  other  results  for  the  alkali  combinations,  namely  ; 
potassium  phosphate  12,  sodium  pliosphate  6.1,  earthy  phosphate  and  iron 
phosphate  4.3,  sodium  chloride  1.4,  and  phosphoric  acid  combined  with 
organic  substances  3.14-2.03  p.  m. 

In  pus  from  congested  abscesses  which  have  stagnated  for  some 
time  we  find  peptone,  leucin,  and  tyrosin,  free  fatty  acids,  and 
volatile  fatty  acids,  such  as  formic  acid,  butyric  acid,  valerianic 
acid.  "We  also  sometimes  find  chondrin  (?)  and  glutin  (?),  urea, 
glucose  (in  diabetes),  liile-pigments  and  Mle-acids  (in  catarrhal 
icterus). 

As  more  specific  but  not  constant  constituents  of  the  pus  we 
must  mention  the  following:  pyin,  which  seems  to  be  a  nucleo- 
albumin  or  nucleoproteid  precipitable  by  acetic  acid,  and  also  pyinic 
acid  and  chlorrhodinic  acid,  which  have  been  so  little  studied  that 
they  cannot  be  more  fully  treated  here. 

In  many  cases  a  blue,  more  rarely  a  green,  color  has  been 
observed  in  the  pus.  This  depends  on  the  presence  of  a  variety  of 
vibrios  (Lucke)  from  which  Fordos  '  and  Lucke  '  have  isolated  a 
crystallizable  coloring  matter  partly  blue  and  partly  yellow,  pyocy- 
anin  and  pyoxarithose. 

Appendix. 

Lymphatic  Glands,  Spleen,  etc. 

The  Lymphatic  Glands.  The  cells  of  the  lymphatic  glands  are 
found  to  contain  the  protein  substances  occurring  generally  in  cells 
(Chapter  V,  p.  90-91).  Albumoses  and  peptones  may  also  occur  as 
products  of  a  post-mortem  decomposition.  Besides  the  other 
ordinary  tissue-constituents,  such  as  collagen,  reticulin,  elastin,  and 
nuclein,  we  find  in  the  lymphatic  glands  also  cholesterin,  fat, 
glycogen,  sarcolactic  acid,  xantliin  bodies,  and  leucin.  In  the 
inguinal  glands  of  an  old  woman  Oidtmajstn  *"  found  714.33  p.  m. 
water,  384.5  p.  m.  organic  and  1.16  p.  m.  inorganic  substances. 

The  Spleen.  The  pulp  of  the  spleen  cannot  be  freed  from 
blood.  The  mass  which  is  separated  from  the  spleen  capsule  and 
the  structural  tissue  by  pressure  and  which  ordinarily  serves  as 
material  for  chemical  investigations  is  therefore  a  mixture  of  blood 
and  spleen  constituents.     For  this  reason  the  albuminous  bodies  of 

'  Compt.  rend.,  Tome  51  and  56. 
2  Arch.  f.  klin.  Chirurg.,  Bd.  3. 
•  V.  Gorup-Besanez,  Lehrbuch,  4.  Aufl.,  S.  732. 


THE  SPLEEN.  201 

the  spleen  are  little  known.  As  characteristic  constituents  we  have 
albuminates  containing  iron,  and  especially  a  protein  substance 
which  does  not  coagulate  on  boiling,  and  which  is  precipitated  by 
acetic  acid  and  yields  an  ash  containing  much  phosphoric  acid  and 
iron  oxide.' 

The  pulj3  of  the  spleen,  when  fresh,  has  an  alkaline  reaction,  but 
quickly  turns  acids,  due  partly  to  the  formation  of  free  paralactic 
acid  and  partly  perhaps  to  glycero-p1ios2)horic  acid.  Besides  these 
two  acids  there  have  been  found  in  the  spleen  also  volatile  fatty 
acids,  as  formic,  acetic,  and  butyric  acids,  as  well  as  succinic  acid, 
neutral  fats,  cholesterin,  traces  of  leucin,  inosit  (in  ox-spleen), 
scyllii,  a  body  related  to  inosit  (in  the  spleen  of  plagiostoma), 
glycogen   (in   dog-spleen),  uric  acid,  xanthin  bodies,   and  jecorin 

(BALDf). 

Among  the  constituents  of  the  sj^leen  the  deposit  rich  in  iro7i, 
which  consists  of  ferruginous  granules  or  conglomerate  masses  of 
them,  and  closely  studied  by  Nasse,  is  of  special  interest.  These 
iron  grains  produced  by  the  transformation  of  the  red  corpuscles, 
and  which  also  occur  in  old  thrombi,  are  chiefly  produced  when 
stagnant  blood-corpuscles  are  not  dissolved,  and  they  may  be  formed 
either  extracellular  or  intracellular  when  the  blood-corpuscles  are 
taken  up  by  the  colorless  cells.  This  deposit  does  not  occur  to  the 
same  extent  in  the  spleen  of  all  animals.  It  is  found  especially 
abundant  in  the  spleen  of  the  horse.  Nasse  ^  on  analyzing  the 
grains  (from  the  spleen  of  a  horse)  obtained  840-630  j).  m.  organic 
and  160-370  p.  m.  inorganic  substances.  These  last  consisted  of 
566-726  p.  m.  Fe,03,  305-388  p.  m.  P,0^,  and  57  p.  m.  earths. 
The  organic  substances  consisted  chiefly  of  proteids  (660-800 
p.  m.),  nuclein,  52  p.  m.  (maximum),  a  yellow  coloring  matter, 
extractive  bodies,  fat,  cholesterin,  and  lecithin. 

In  regard  to  the  mineral  constituents  it  is  to  be  observed  that 
the  amount  of  iron  in  adults  is  strikingly  large,  and  farther  that 
the  amount  of  sodium  and  phosphoric  acid  is  smaller  than  that  of 
potassium  and  chlorine.  The  amount  of  iron  in  new-born  and 
young  animals  is  small  (Lapicque,^  Kkuger,  and  Perjstou"),  in 

'  V,  Gorup-Besanez,  Lehrbuch,  4.  Aufl.,  S.  717. 

'  Du  Bois-Reymond's  Arch.,  188T,  Suppl. 

'  Maly's  Jahresber.,  Bd.  19,  S.  315. 

*i6id.,  20,  S.  268 

6  Zeitschr.  f.  Biologie,  Bd.  27. 


202    CHYLE,  LYMPH,  TRAN8UDATL0N8  AND  EXUDATL0N8. 

adults  more  appreciable,  and  in  old  animals  sometimes  very  con- 
siderable. Nasse  '  found  nearly  50  p.  m.  iron  in  the  dried  palp  of 
the  spleen  of  an  old  horse. 

The  quantitative  analyses  of  the  human  spleen  by  Oidtmann  * 
give  the  following  results:  In  men  he  found  750-694  p.  m.  water 
and  250-306  p.  m.  solids.  In  that  of  a  woman  he  found  774.8 
p.  m.  water  and  225.2  p.  m.  solids.  The  quantity  of  inorganic 
bodies  was  in  men  4.9-7.4  p.  m.,  and  in  women  9.5  p.  m. 

In  regard  to  the  pathological  processes  going  on  in  the  spleen 
we  must  specially  recall  the  abundant  re-formation  of  leucocytes  in 
leucaemia  and  the  appearance  of  amyloid  substance  (see  page  57). 

The  physiological  functions  of  the  spleen  are  little  known  with 
the  exception  of  its  importance  in  the  formation  of  leucocytes. 
Some  consider  the  spleen  as  an  organ  for  the  dissolution  of  the  red 
blood-corpuscles,  and  the  occurrence  of  the  above-mentioned  deposit 
rich  in  iron  seems  to  confirm  this  view.  Other  investigators  regard 
the  spleen  as  a  blood-forming  organ.  Several  investigators  claim 
the  occurrence  of  nucleated  preliminary  steps  in  the  formation  of 
red  corpuscles  in  the  spleen  or  of  younger  red  corpuscles  in  the 
blood  of  the  splenic  vein. 

The  spleen  has  also  been  claimed  to  play  an  important  part  in 
digestion.  The  organ  is  known  to  enlarge  after  a  meal,  and  this 
enlargement  is  thought  by  Schiff  '  and  Herzen  ^  to  be  connected 
with  the  filling  of  the  pancreas  with  enzymes.  According  to  the 
above-mentioned  investigators,  after  the  extirpation  of  the  spleen 
the  pancreas  does  not  produce  any  enzyme  which  digests  proteids, 
but  Heidenhetm  '  and  Ewald  "  have  not  been  able  to  confirm  this 
fact.  According  to  later  investigations  of  Herzen",'  an  enzyme 
which  digests  proteids  is  produced  in  the  spleen  during  its  enlarge- 
ment. 

An  increase  in  the  quantity  of  uric  acid  eliminated  has  been 
observed  by  many  investigators  (see  Chapter  XV)  in  lineal  leu- 
caemia, while  the  reverse  has  been  observed  under  the  influence  of 

1  Cit.  from  Hoppe-Seyler's  Physiol.  Chem.,  S.  730. 

^  Cit.  from  v.  Gorup-Besanez,  Lehrbucb,  4.  Aufl.,  S.  719. 

3  Arch.  f.  Heillmnde,  Bd.  3,  Schweiz.  Zeitschr.  f.  wiss.  Med.,  1862. 

4  Pfiuger's  Arch  ,  Bd.  30,  S.  295  and  308. 

6  L.  Hermann's  Handb.  d.  Physiol. ,  Bd.  5,  S.  806. 
*  Verhandl.  d.  physiol.  Ges.  in  Berlin,  1878. 
'  Maly's  Jahresber.,  Bd.  18,  S.  192. 


THE  THYMUS.  203 

quinin  ia  large  doses,  which  produces  an  enlargement  of  the  spleen. 
We  have  here  a  rather  positive  proof  that  there  is  a  close  relation- 
ship between  the  spleen  and  the  formation  of  nric  acid.  This 
relationship  has  lately  been  studied  by  Hoebaczewski.'  He  has 
shown  that  when  the  spleen  pulp  and  blood  of  calves  is  allowed  to 
act  on  each  other,  under  certain  conditions  and  temperature,  in  the 
presence  of  air,  large  quantities  of  uric  acid  are  formed.  Under 
other  conditions  he  obtained  from  the  spleen  pulp  only  xanthin 
bases  with  no  or  very  little  uric  acid.  Hoebaczewski  has  also 
shown  that  the  uric  acid  originates  from  the  nucleins  of  the  spleen, 
which  yield  uric  acid  and  xanthin  bases  accordiug  to  the  experi- 
mental conditions. 

The  spleen  has  the  same  property  as  the  liver  of  retaining 
foreign  bodies,  metals  and  metalloids. 

The  Thymus.  Besides  proteids  and  substances  belonging  to  the 
connective  group,  we  find  small  quantities  of  fat^  leucin,  succinic 
acid,  lactic  acid,  and  glucose.  The  large  quantity  of  xanthin  bodies, 
chiefly  adenin,  is  remarkable — 1.79  p.  m.  in  the  fresh  gland,  or 
19.19  p.  m.  in  the  dried  substance  (Kossel  and  Schikblee'). 
LiLiENFELD  ^  has  found  inosit  and  jjrotagon  in  the  cells  of  the 
thymus.  The  quantitative  composition  of  the  lymphocytes  of  the 
thymus  of  a  calf  is,  according  to  Lilienfeld's  ^  analysis,  as  fol- 
lows.    The  results  are  given  in  1000  parts  of  the  dried  substance. 

Proteids 17.6 

Leuconuclein 687.8 

Histon , 86. 7 

Lecithin 75.1 

Fat 40.2 

Cliolesterin 44  0 

Glycogen 8.0 

The  dried  substance  of  the  leucocytes  amounted  to  an  average 
of  114.9  p.  m.  Potassium  and  phosphoric  acid  are  prominent 
mineral  constituents.  Lilienfeld  found  KH^PO,  amongst  the 
bodies  soluble  in  alcohol.  Oidtmanist  '  found  807.06  p.  m.  water, 
192.74  p.  m.  organic  and  0.3  p.  m.  inorganic  substances  in  the  gland 
of  a  child  two  weeks  old. 

'  Monatshefte  f.  Chem.,  1889,  and  Wien.  Sitzungsber.  1891,  Math.  Naturw. 
Klasse,  Abthl.  3. 

»  Zeitschr.  f.  physiol.  Chem.,  Bd.  13. 

*  Ibid.,  Bd.  18,  S.  473. 
"L.  c. 

*  Cit.  from  v.  Gorup-Besanez,  Lehrbuch,  4.  Aufl.,  S.  733. 


204    CHYLE,  LYMPH,   TBAN8UBATI0NS  AND  EXUDATIONS. 

The  Thyroid  Gland.  The  chemical  constitaeuts  of  this  gland 
are  little  known.  Bubjstow  ^  has  obtained  a  protein  substance 
called  by  him  "  thyreopi^oteine,''^  by  extracting  the  gland  with 
common-salt  solution  or  by  very  dilute  caustic  potash.  This  body 
has  about  the  same  amount  of  nitrogen,  but  smaller  amounts  of 
carbon  and  hydrogen  than,  the  proteids  in  general.  The  fluid  found 
in  the  vesicle  sometimes  contains  a  mudn-like  substance  which  is 
precipitated  by  an  excess  of  acetic  acid.  Gourlat  "^  could  not  find 
any  mucin  but  only  a  nucleoalbnmin  in  the  thyroid  gland  of  oxen. 
Besides  these,  other  substances  have  been  found  in  the  extract  of 
the  glands,  such  as  leucin,  xanthin,  liypoxanthin,  lactic  and  succinic 
acids.  OiDTMAiiTN '  found  in  the  thyroid  gland  of  an  old  woman 
822.4  p.  m,  water,  176.7  p.  m.  organic  and  0.9  p.  m.  inorganic 
substances.  He  found  772.1  p.  m.  water,  223.4  p.  m.  organic  and 
4,5  p.  m.  inorganic  substances  in  an  infant  two  weeks  old. 

In  "  STEUMA  CYSTICA  "  Hoppe-Setlee  found  hardly  any  pro- 
teid  in  the  smaller  glandular  vessels,  but  an  excess  of  mucin,  while 
in  the  larger  he  found  a  great  deal  of  proteid,  70-80  p.  m." 
ChoUsterin  is  regularly  found  in  such  cysts,  sometimes  in  such  large 
quantities  that  the  entire  contents  form  a  thick  mass  of  cholesterin 
plates.  Crystals  of  calcium  oxalate  also  occur  frequently.  The 
contents  of  the  struma  cysts  are  sometimes  of  a  brown  color  due  to 
decomposed  coloring  matter,  metJimmoglohin  (and  hsematin?).  Bile- 
coloring  matters  have  also  been  found  in  such  cysts.  (In  regard  to 
the  paralhumi7is  and  colloids  which  have  been  found  in  struma 
cysts  and  colloid  degeneration,  see  Chapter  XIII.) 

Little  is  known  in  regard  to  the  functions  of  the  thyroid  gland. 
From  a  chemical  standpoint  the  view  is  worth  suggesting  that  the 
so-called  myxoedema,  which  is  a  slimy  infiltration  or  abundant 
extuberance  of  the  connective  tissue  of  the  subcutaneous  cell-tissue 
especially  of  the  head  and  throat  (besides  other  disturbances)  stands 
in  connection  with  the  failing  of  the  activity  of  the  thyroid  gland. 
HoESLET  and  Hallibueton'  found  in  monkeys,  but  not  in  pigs, 
that  the  amount  of  mucin  in  the  tissue  was  increased  after  extirpat- 
ing the  thyroid  gland. 

•  Zeitsclir.  f.  physiol.  Chem.,  Bd.  8. 
»  Journal  of  Physioi.,  Vol.  16. 

2  Cit.  from  v.  Gorup  Besanez,  Lehrbuch,  S.  732. 

*  Hoppe-Sevler,  Physiol.  ChRm.,  S.  721. 

'  Brit.  Med,  Journ.,  1885  ;  also  Maly's  Jahresber.,  Bd.  18,  S.  324. 


TEE  SUPRAREXAL   CAPSULE.  205 

We  ha^e  no  explanation  as  to  the  action  of  the  gland  in  these 
cases.  In  consideration  of  the  very  favorable  therapeutical  results 
which  have  been  obtained  in  many  cases  of  myxcedema  by  the 
injection  of  a  watery  or  glycerin  extract  of  the  gland  or  the  admin- 
istration of  the  gland  of  sheep,  it  seems  probable  that  myxoedema 
is  caused  by  an  intoxication  produced  by  metabolic  products,  which 
are  otherwise  destroyed  or  made  harmless  by  the  gland. 

The  Suprarenal  Capsule. — Besides  proteids,  substances  of  the 
connective  tissue,  and  salts,  we  find  in  the  suprarenal  capsule 
inosit,  palmitin,  lecithin,  Jieurin,  and  glycero-phosjiihoric  acid, 
which  last  gives  the  poisonous  projDerties  of  the  watery  extract  of  the 
gland  (Makino-Zuco  and  Guaexieei  '),  and  some  leucin,  which 
is  probably  a  decomposition  product.  The  statement  that  benzoic 
acid,  hijjjjicric  acid,  and  biliary  acids  occur  in  this  gland  could 
not  be  confirmed  by  Stadelmann.'  In  the  medulla  there  have 
been  found  one  or  more  chromogens  which  are  converted  into  a  red 
pigment  by  the  action  of  air,  light,  warmth,  haloid  or  metallic  salts 
(VuLPiAN,  Krukenberg^).  Pyrocatechin  also  probably  occurs 
therein.  Because  of  the  amount  of  chromogen  contained  in  the 
suprarenal  body,  a  connection  is  claimed  between  the  abnormal 
deposition  of  pigment  in  the  skin,  which  is  characteristic  of  Addi- 
sox's  disease,  and  the  diseased  changes  which  often  occur  in  the 
suprarenal  body. 

Nothing  positive  is  known  as  to  the  functions  of  the  suprarenal 
capsule.  The  extirpation  of  the  suprarenal  capsule  of  a  dog  is 
always  a  fatal  operation  (Laxglois).  Death  is  hastened  by  the 
injection  of  blood  from  an  animal  killed  by  this  operation,  while 
the  blood  from  a  healthy  animal  has  no  action.  Perhaps  we  have 
here  also  to  deal  with  an  intoxication  produced  by  metabolic 
products,  which  are  made  harmless  or  destroyed  by  the  suprarenal 
capsules  under  normal  conditions.  The  investigations  of  Abelous 
and  Laxglois  and  others  seem  to  confirm  this  view 

1  Maly's  Jahresber.,  Bd.  18,  S.  231. 
'  Zeitschr.  f.  physiol.  Chem.,  Bd.  18. 
*  Vircliow's  Arch.,  Bd.  101. 


CHAPTER  VIII. 

THE   LIVER. 

The  liver,  which  is  the  largest  organ  of  the  body,  stands  in  close 
relationship  to  the  blood-forming  organs.  The  importance  of  this 
organ  in  the  physiological  composition  of  the  blood  is  evident  from 
the  fact  that  the  blood  coming  from  the  digestive  tract,  laden  with 
absorbed  bodies,  must  circulate  through  the  liver  before  it  is  driven 
by  the  heart  through  the  different  organs  and  tissues.  It  has  been 
proved,,  at  least  for  the  carbohydrates,  that  an  assimilation  of  the 
absorbed  nutritive  bodies  which  are  brought  to  the  liver  by  the 
blood  of  the  portal  vein  takes  place  in  this  organ.  The  occurrence 
of  synthetical  processes  in  the  liver  has  been  positively  proved  by 
special  observations.  It  is  possible  that  in  the  liver  certain  am- 
monia combinations  are  converted  into  urea  or  uric  acid  (in  birds), 
while  certain  products  of  putrefaction  in  the  intestine,  such  as 
phenol,  may  be  converted  by  synthesis  into  ethereal  sulphuric  acids 
by  the  liver  (Pflugee  and  Kochs  ^).  The  liver  has  also  the  prop- 
erty of  removing  and  retaining  heterogeneous  bodies  from  the 
blood,  and  this  is  not  only  true  of  metallic  salts,  which  are  often 
retained  by  this  organ,  but  also,  as  Schiff,  Lauteistbekgee, 
Jacques,  Heger,  and  Roger  ^  have  shown,  the  alkaloids  are 
retained  and  are  probably  partially  decomposed  in  the  liver.  Toxins 
are  also  retained  by  the  liver  and  hence  this  organ  has  a  protective 
action  against  poisons. 

Even  though  the  liver  is  of  assimilatory  importance  and  purifies 
the  blood  coming  from  the  digestive  tract,  it  is  at  the  same  time  a 
secretory  organ  which  eliminates  a  specific  secretion,  the  bile,  in  the 

1  Pfliiger's  Arch.,  Bd.  20  and  Bd.  23,  S.  169. 

'■^  Roger,  Action  du  foie  sur  les  poisons  (Paris,  1887)  ;  Bouchard.  Legons 
sur  les  autointoxications  dans  les  Maiadies  (Paris,  1887);  and  B,  Kotliar  in 
Arcli.  des  sciences  biologique  de  St,  Peterstaou-rg,  Tome  2,  No.  4,  p.  587. 

206 


THE  LIVER  SUBSTANCE.  207 

production  of  which  the  red  blood-corpuscles  are  destroyed,  or  at 
least  one  of  their  constituents,  the  haemoglobin.  It  is  generally 
admitted  that  the  liver  acts  contrariwise  daring  foetal  life,  at  that 
time  forming  the  red  blood-corpuscles. 

There  is  no  doubt  that  the  chemical  operations  going  on  in  this 
organ  are  manifold  and  must  be  of  the  greatest  importance  for  the 
organism;  but  unfortunately  we  know  very  little  about  the  kind 
and  extent  of  these  processes.  Among  them  are  two  principal  ones 
which  will  be  fully  treated  in  this  chapter,  after  we  have  first 
described  the  constituents  and  the  chemical  composition  of  the 
liver.  One  of  these  processes  seems  to  be  of  an  assimilatory  nature 
and  refer  to  the  formation  of  glycogen,  while  the  other  refers  to 
the  production  and  secretion  of  the  bile. 

The  reaction  of  the  liver-cell  is  alkaline  during  life,  but 
becomes  acid  after  death.  This  change  is  probably  due  to  the 
formation  of  lactic  acid,  causing  a  coagulation  of  the  proteids  of  the 
protoplasm  of  the  cell.  A  positive  difference  between  the  albu- 
minous bodies  of  the  dead  and  the  living,  non-coagulated  proto- 
plasm has  not  been  observed. 

The  proteids  of  the  liver  were  first  carefully  investigated  by 
Plosz.'  He  found  in  the  watery  extract  of  the  liver  an  albmninous 
substance  which  coagulates  at  -|- 45°  C,  also  a  globulin  which 
coagulates  at  +  75°  C,  a  micleoalbumin  which  coagulates  at 
+  70°  C,  and  lastly  a  proteid  body  which  is  nearly  related  to 
coagulated  albumiiis  and  which  is  insoluble  iu  dilute  acids  or 
alkalies  at  the  ordinary  temperature,  but  dissolves  on  the  applica- 
tion of  heat,  being  converted  into  an  albuminate.  Halliburtox  " 
has  found  two  globulins  in  the  liver-cells,  one  of  which  coagulates 
at  68-70°  C,  and  the  other  at  45-50°  C.  He  also  found,  besides 
traces  of  albumin,  a  nucleoalbumin  (nucleoproteid)  which  contained 
1.45^  phosphorus  and  a  coagulation-point  of  60°  C.  The  liver- 
cells  contain,  besides  these  j)roteids,  a  large  quantity  of  difiicultly 
soluble  protein  bodies  (see  Plosz).  St.  Zaleski  '  has  found  in  the 
liver  a  proteid  containing  iron,  in  which  the  iron  is  more  or  less 
strongly  combined.  It  is  unknown  what  relation  this  bears  to  the 
above-mentioned  proteids. 

The  fat  of  the  liver  occurs  partly  as  very  small  globules  and 

»  Pflilger's  Arch.,  Bd.  7. 

«  Journal  of  Physiol.,  Vol.  13,  Suppl.  1893. 

^Zeitschr.  f.  physiol.  Chem.,  Bd.  10,  S.  486. 


208  THE  LIVER. 

partly,  especially  in  nursing  children  and  sucking  animals,  as  also 
after  food  rich  in  fat,  as  rather  large  fat-drops.  This  infiltration 
of  fat,  which  may  be  made  so  abundant  by  proper  food  that  it 
appears  similar  in  the  highest  degree  to  a  pathological  fatty  liver, 
begins  in  the  periphery  of  the  acini  and  extends  towards  the  centre. 
If  the  amount  of  fat  in  the  liver  is  increased  by  an  infiltration,  the 
water  decreases  correspondingly,  while  the  quantity  of  the  other 
solids  remains  little  changed.  In  fatty  degeneration  this  is  differ- 
ent. In  this  process  the  fat  is  formed  from  the  protoplasm  of  the 
cell,  and  the  quantity  of  the  other  solids  is  therefore  diminished 
while  the  amount  of  water  is  only  slightly  changed.  To  illustrate 
this,  we  give  below  the  results  from  a  normal  liver,  and  also  the 
results  obtained  by  Perls  '  in  fatty  degeneration  and  fatty  infiltra- 
tion.    The  results  are  in  1000  parts. 

Water.  Fat.  Remaining  Solids. 

Normal  liver 770  20-35            207-195 

Fatty  degeneration 816  87                    97 

Fatty  infiltration 616-621  195-340          184-145 

Among  the  extractive  substances  besides  glycogen,  which  will  be 
treated  of  later,  we  find  rather  large  quantities  of  xanthin  bases. 
Kossel"  found  in  1000  parts  of  the  dried  substance  1.97  p.  m. 
guanin,  1.34  p.  m.  hypoxanthin,  and  1.21  p.  m.  xanthin.  Adenin 
is  also  contained  in  the  liver.  In  addition  there  have  been  found 
urea  and  uric  acid  (especially  in  birds),  and  indeed  in  larger  quan- 
tities than  in  the  blood,  paralactic  acid,  leucin,  jecoriti,  and  cystin. 
In  pathological  cases  inosit  and  tyrosin  have  been  detected.  The 
occurrence  of  bile-coloring  matters  in  the  liver-cell  under  normal 
conditions  is  doubtful;  but  in  retention  of  the  bile  the  cells  may 
absorb  the  coloring  matter  and  become  colored  thereby. 

Jecorin  was  first  found  by  Drechsel^  in  the  liver  of  a  liorse,  and  later  by 
Baldi*  in  the  liver  and  spleen  of  other  animals,  in  the  muscles  and  blood  of  the 
horse,  and  in  the  human  brain.  It  contains  sulphur  and  phosphorus,  but  its 
constitution  is  not  positively  known.  Jecorin  dissolves  in  ether,  but  is  precip- 
itated from  this  solution  by  alcohol.  It  reduces  co]iper  oxide,  and  it  solidifies 
after  boiling  with  alkalies  to  a  gelatinous  mass.  It  may  lead  to  errors  in  the 
invesiigalions  of  organs  or  tissues,  for  it  can  easily  be  mistaken  for  lecithin  on. 
account  of  its  solubilities  and  because  it  contains  phosphorus. 

The  mineral  bodies  of  the  liver  consist  of  phosphoric  acid, 
potassium,  sodium,  alkaline  earths,  and  chlorine.     The  potassium 

>  Centralbl.  f.  d.  med.  Wissensch.,  Bd.  11,  S.  801. 
•"  Zeitschr.  f.  physiol.  Chem.,  Bd.  8,  S.  408. 

3  Ber.  d.  sSchs.  Ges.  d.  Wissensch.,  1886,  S.  44. 

4  Du  Bois-Reymond's  Arch.,  Physiol.  Abth.,  1887.     Suppl.  S.  100. 


IROX  IN  THE  LIVER-CELLS.  209 

is  in  excess  of  tlis  sodium.  Iron  is  a  regular  constituent  of  the 
liver,  but  in  very  variable  amounts,  0.3-11.8  p.  m.  calculated  for 
the  dried  substance  of  the  liver  of  different  animals  (St.  Zaleski  '). 
Bt'NGE^  has  found  0.01-0.355  p.  m.  iron  in  the  blood-free  liver  of 
young  cats  and  dogs.  This  was  calculated  on  the  liver  substance 
freshly  washed  with  a  1%  NaCl  solution.  Calculated  on  10  kilos 
bodily  weight,  the  iron  in  the  livers  amounted  to  3.4-80.1  mgm. 

The  richness  of  the  liver  of  new-born  animals  in  iron  is  of 
special  interest;  a  condition  which  follows  from  the  analyses  of 
St.  Zaleski,  but  especially  studied  by  Kruger,  Meyer,  and 
Pernou.'  In  oxen  and  cows  they  found  0.246-0.276  p.  m.  iron 
(calculated  on  the  dry  substance),  and  in  the  cow  foetus  about  ten 
times  as  much.  The  liver-cells  of  a  calf  a  week  old  contain  about 
seven  times  as  much  iron  as  the  full-grown  animal;  the  quantity 
sinks  in  the  first  four  weeks  of  life,  when  it  about  reaches  the  same 
amount  as  in  the  grown  animal.  Lapicque  *  has  also  found  tliat  in 
rabbits  the  quantity  of  iron  in  the  liver  steadily  diminishes  from  the 
eighth  day  to  three  months  after  birth,  namely,  from  10  to  0.4  p.  m.^ 
calculated  on  the  dry  substance.  "  The  foetal  liver-cells  bring  an 
abundance  of  iron  into  the  world  to  be  used  up,  within  a  certain 
time,  for  a  purpose  not  well  known."  A  part  of  the  iron  exists  as. 
phosphate,  and  the  greater  part  in  combination  with  the  protein 
bodies  (St.  Zaleski).  F.  Kruger'*  has  determined  the  quantity 
of  calcium  in  the  liver-cells  of  oxeu  in  various  stages  of  development, 
and  has  found  that  the  average  quantity  was  only  0.71  p.  m.  of  the 
dried  substance  in  full-grown  oxen  and  1.23  p.  m.  in  calves.  In 
the  foetus  of  the  cow  it  is  lower  than  in  calves,  but  it  shows  two 
maxima  during  foetal  life,  one  in  the  first  to  the  fifth  month,  and 
the  other  in  the  tenth  month,  of  pregnancy.  At  these  times  the 
liver-cells  contain  about  45^  more  calcium  than  in  full-grown  oxen. 
During  pregnancy  the  iron  and  calcium  are  antagonistic;  namely, 
an  increase  in  the  quantity  of  calcium  causes  a  diminution  in  the 
iron,  and  an  increase  in  the  iron  causes  a  decrease  in  the  calcium, 
Kruger  found  23.8  p.  m.  sulphur,  12.8  j).  ni.  phosj)horus,  and 
0.55  p.  m.  iron  in  the  liver-cells  of  adult  persons  and  35.6  p.  m. 

'  L.  c,  S.  464-479. 

5  Zeitscbr.  f.  plivsiol.  Chem.,  Bd.  17,  S.  78. 

'Zeitsehr.  f.  Biologic,  Bd.  27,  S.  439. 

*  Maly's  Jahresber.,  Bd.  20,  S.  268. 

5  Zeitschr.  f.  Biologie,  Bd.  31. 


210  THE  LIVER. 

sulphur,  15.4  p.  m.  phosphorus,  and  3.14  p.  m.  iron  in  those  of 
new-born  infants.  Copper  seems  to  be  a  physiological  constituent. 
Foreign  metals,  such  as  lead,  zinc,  and  others  (also  iron),  are  easily 
taken  up  and  retained  for  a  long  time  by  the  liver. 

V,  BiBEA  '  found  in  the  liver  of  a  young  man  who  had  suddenly 
died,  762  p.  m.  water  and  238  p.  m.  solids,  consisting  of  25  p.  m. 
fat,  152  p.  m.  proteid  and  gelatin-forming  substance,  and  61 
p.  m.  extractive  substances. 

Glycogen  and  its  Formation. 

Glycogen  was  discovered  by  Beexard  and  HE^rsEisr  *  independ- 
ently of  each  other.  It  is  a  carbohydrate  closely  related  to  the 
starches  or  dextrins  with  the  general  formula  C^Hj^O^,  perhaps 
6(C,Hj„0J  +  H^O  (KuLZ  and  Borxtrager').  The  largest  quan- 
tities are  found  in  the  liver  of  full-grown  animals,  and  smaller 
quantities  in  the  muscles  (Bernard,  Nasse  ').  It  is  found  in  very 
small  quantities  in  nearly  all  tissues  of  the  animal  body.  Its  occur- 
rence in  lymphoid  cells,  blood,  and  pus  has  been  mentioned  in  . 
previous  chapter,  and  it  seems  to  be  a  regular  constituent  of  all  cells 
capable  of  development.  Glycogen  was  first  shown  to  exist  in 
embryonic  tissues  by  Berxaed  and  Kuhxe,"  and  it  seems  on  the 
whole  to  be  a  constituent  of  such  tissues  in  which  a  rapid  cell- 
formation  and  cell-development  is  taking  place.  It  is  also  present 
in  rapidly  forming  pathological  swellings  (Hoppe-Setler  ').  Cer- 
tain animals,  as  certain  muscles,  are  very  rich  in  glycogen  (Bizio  '). 
G-lycogen  also  occurs  in  the  plant  kingdom,  especially  in  many 
fungi. 

The  quantity  of  glycogen  in  the  liver,  as  also  in  the  muscles, 
depends  essentially  upon  the  food.  In  starvation  it  disappears 
nearly  completely  after  a  short  time,  but  more  rapidly  in  small  than 
in  large  animals.  According  to  the  old  views  it  disappears  earlier 
from  the  muscles  than  from  the  liver.     According  to  the  later 

'  See  V.  Gorup-Besanez,  Letrbucli,  4.  Aufl.,  S.  711. 

2  CI.  Bernard,  Comp.  rend.,  Tome  44,  p.  578;  and  Hansen,  Vircliow's  Arch., 
Bd.  11,  S.  395. 

3  Pfluger's  Arch.,  Bd.  24,  S.   19. 
*lbid.,  Bd.  2,  S.  97. 

'  See  Killine,  Lehrb.  d.  physiol.  Chem.,  1868,  S.  307. 
«  Pfluger's  Arcli.,  Bd.  7,  S.  409. 
'  Comp.  rend..  Tome  62,  p.  67.5. 


GLYCOGEN,  211 

determinations  of  Aldehoff  '  on  hens,  pigeons,  rabbits,  cats,  and 
horses,  which  have  been  confirmed  by  Kulz  and  Hergenhahn  * 
and  others,  the  muscle  glycogen  has  a  greater  resistance  to  destruc- 
tion than  liver  glycogen.  After  partaking  of  food  especially  abun- 
dant in  carbohydrates,  the  liver  becomes  rich  again  in  glycogen,  the 
greatest  increment  occurring  14  to  16  hours  after  eating  (Kulz  ^). 
Hekgexhahx  found  on  experiments  with  hens  that  the  appearance 
of  the  maximum  of  glycogen  in  the  liver  was  also  dependent  upon 
the  quantity  of  carbohydrates  partaken  of.  The  maximum  of  liver 
glycogen  was  reached  on  supplying  10  gms.  cane-sugar  in  12  hours, 
and  after  30  gms.  in  20  hours.  The  maximum  of  muscle  glycogen 
is  reached  after  20-24  hours,  independently  of  the  quantity  of  cane- 
sugar  supplied.  The  quantity  of  liver  glycogen  may  amount  to 
120-160  p.  m.  after  partaking  of  large  quantities  of  carbohydrates. 
Ordinarily  it  is  considerably  less,  namely,  12-30  to  40  jd.  m. 

The  quantity  of  glycogen  of  the  liver  (and  also  the  muscles)  is 
also  dependent  upon  rest  and  activity,  because  during  activity  the 
quantity  diminishes.  Kulz  *  has  shown  that  by  hard  work  the 
quantity  of  glycogen  in  the  liver  (of  dogs)  is  reduced  to  a  minimum 
in  a  few  hours.  The  muscle  glycogen  does  not  diminish  to  the 
same  extent  as  the  liver  glycogen.  Kulz  was  able  to  completely 
consume  the  liver  as  well  as  the  muscle  glycogen  of  a  rabbit  in  3-5 
hours  by  qualified  strychnin  poisoning. 

Glycogen  forms  an  amorphous,  white,  tasteless,  and  inodorous 
powder.  It  gives  an  opalescent  solution  with  water  which,  when 
allowed  to  evaporate  in  the  water-bath,  forms  a  pellicle  over  the 
surface  that  disappears  again  on  cooling.  The  solution  is  dextro- 
gyrate, (a-)  D  =  +  196°.63  (Huppert').  The  specific  rotatory 
power  is  given  somewhat  differently  by  various  investigators.  A 
solution  of  glycogen,  especially  on  the  addition  of  NaCl,  is  colored 
wiue-red  by  iodine.  It  may  hold  copper  oxyhydrate  in  solution  in 
alkaline  liquids,  but  does  not  reduce  it.  A  solution  of  glycogen 
in  water   is  not  precipitated   by  potassium-mercuric   iodide   and 

^  Zeitschr.  f.  Biologie,  Bd.  25,  S.  137.  Contains  a  summary  of  the  literature. 

*  Ibid.,  Bd.  27,  S.  214. 

*  Pfliiger's  Arch.,  Bd.  24,  S.  1-114.    This  important  article  contains  numer- 
ous data  in  regard  to  the  literature  of  the  glycogen  question. 

*  Pfliiger  s  Arch.,  Bd.  24,  and  "  Beitrage    zur  Kenntniss  des  Qlykogens." 
C.  Lud wig's  Festschrift     Marburg,  1891. 

5  Zeitschr.  f.  physiol.  Chem.,  Bd.  18,  S.  137. 


212  THE  LIVER. 

hydrocliloric  acid,  but  is  precipitated  by  alcobol  (on  the  addition  of 
NaCl  when  necessary)  or  ammoniacal  lead  acetate.  It  gives  a- 
white  granular  precipitate  of  benzoyl  glycogen  with  benzoyl  chlo- 
ride and  caustic  soda.  Glycogen  is  not  decomposed  on  prolonged 
boiling  with  dilute  caustic  potash,  but  it  seems  to  be  changed 
slightly  (ViNTSCHGATJ  and  Dietl  ').  By  diastatic  enzymes  glyco- 
gen is  converted  into  maltose  or  dextrose,  depending  upon  the 
nature  of  the  enzyme.  It  is  transformed  into  dextrose  by  dilute 
mineral  acids. 

The  preparation  of  pure  glycogen  (simplest  from  the  liver)  is 
generally  performed  by  the  method  suggested  by  Brucke,  of  which 
the  main  points  are  the  following:  Immediately  after  the  death  of 
the  animal  the  liver  is  thrown  into  boiling  water,  then  finely  divided 
and  boiled  several  times  with  fresh  water.  The  filtered  extract  is 
now  sufficiently  concentrated,  allowed  to  cool,  and  the  proteids 
removed  by  alternately  adding  potassium -mercuric  iodide  and 
hydrochloric  acid.  The  glycogen  is  precipitated  from  the  filtered 
liquid  by  the  addition  of  alcohol  until  the  liquid  contains  60  vols. 
per  cent.  The  glycogen  is  first  washed  on  the  filter  with  60^  and 
then  with  95^  alcohol,  then  treated  with  ether  and  dried  over  sul- 
phuric acid.  It  is  always  contaminated  with  mineral  substances. 
To  be  able  to  extract  the  glycogen  from  the  liver  or  especially  from 
muscles  and  other  tissues  completely,  which  is  essential  in  a  quan- 
titative estimation,  these  parts  must  first  be  boiled  for  a  few  hours 
with  a  dilute  solution  of  caustic  potash,  say  4  gms.  KOH  to  100 
gms.  liver  and  400  c.c.  water  (Kulz). 

Proteid-free  glycogen  may  be  prepared  according  to  the  method 
suggested  by  Huizinga,'  in  which  the  liver  tissue  k  extracted  with 
a  mixture  of  equal  volumes  of  a  saturated  mercuric-ciiJoride  solution 
and  Esbach's  reagent  (10  gm.  picric  acid  and  20  gms.  citric  acid 
in  a  liter).  The  glycogen  is  precipitated  by  alcohol  and  treated 
with  alcohol  and  ether. 

The  quantitative  estimation  is  best  performed  according  to  the 
described  method  of  Beucke-Kulz.°  It  is  to  be  observed  that  it  is 
necessary  to  heat  the  liver  for  2-3  hours  and  muscle  4-8  hours  with 
caustic-potash  solution.  This  liquid  must  not  be  concentrated  too 
far,  and  must  not  contain  more  than  2^  caustic  potash.  It  is 
neutralized  by  hydrochloric  acid  and  precipitated  by  the  alternate 
addition  of  potassium-mercuric  iodide  and  hydrochloric  acid.  The 
precipitate  must  be  removed  from  the  filter  at  least  four  times,  sus- 
pended in  water  with  the  addition  of  a  few  drops  HCl  and  potas- 
sium-mercuric iodide,  and  refiltered  so   that  all  the  glycogen   is 

1  Pfluger's  Arch.,  Bd.  13,  S.  253. 

2  Pfluger's  Arch.,  Bd.  61. 

3  See  R.  Ktilz,  Zeitschr.  f.  Biologie,  Bd.  23,  S.  161. 


PREPARATION  OF  OLYCOOEN.  213 

■obtained  in  the  filtrates.  These  are  then  precipitated  with  double 
their  volume  of  alcohol,  filtered  after  12  hours,  the  precipitate 
dissolved  in  a  little  warm  water,  treated  on  cooling  with  HCl  and 
potassium-mercuric  iodide,  filtered,  and  the  filtrate  again  precipi- 
tated with  alcohol.  Filter  and  carefully  wash  the  contents  of  the 
filter  with  alcohol  and  ether,  dry,  weigh,  and  incinerate  to  deter- 
mine the  quantity  of  ash  present. 

It  sometimes  happens  that  the  liquid,  after  complete  precipita- 
tion of  the  proteids  with  HCl  and  potassium-mercuric  iodide,  is 
cloudy  and  does  not  filter  clear.  In  this  case  add  2-2^  vols.  95^ 
alcohol  according  to  Pfluger's'  suggestion.  After  the  liquid 
becomes  clear  and  the  precipitate  has  settled  it  can  be  filtered. 
The  precipitate  is  dissolved  in  a  2^  caustic-potash  solution  and 
again  precipitated  by  hydrochloric  acid  and  potassium-mercuric 
iodide.     Then  proceed  as  above  described. 

The  new  method  as  suggested  by  Feankel,"  in  which  the 
glycogen  is  extracted  from  tlie  tissues  by  a  3-4^  water  solution  of 
trichloracetic  acid,  seems  not  to  be  reliable,  according  to  Weidbn- 

BAUM." 

Numerous  investigators  have  endeavored  to  determine  the  origin 
of  glycogen  in  the  animal  body.  It  is  positively  established  by  the 
unanimous  observations  of  many  investigators  ^  that  the  varieties  of 
sugars  and  their  anhydrides,  dextrms  and  starches,  have  the  prop- 
erty of  increasing  the  quantity  of  glycogen  in  the  body.  The  state- 
ments are  somewhat  disputed  in  regard  to  the  action  of  the  pentoses. 
Cremer  *  found  that  various  pentoses  such  as  rhaminose,  xylose, 
and  arabinose  have  a  positive  influence  on  the  glycogen  formation 
in  rabbits  and  hens,  and  Salkowski°  obtained  the  same  result  on 
feeding  rabbits  and  a  hen  on  arabinose.  Frektzel  '  found,  on  the 
contrary,  no  glycogen  formation  on  feeding  xylose  to  a  rabbit  which 
had  previously  been  made  glycogen-free  by  strychnin  poisoning. 

The  hexoses,  and  the  carbohydrates  derived  therefrom,  do  not 
all  possess  the  ability  of  forming  or  accumulating  glycogen  to  the 
same  extent.     Thus  C.  Voit  *  and   his   pupils   have   shown   that 

1  Pfluger's  Arcli.,  Bdd.  53  and  55. 
^  Ibid.,  Bdd.  53  and  55. 
^Ibid.,  Bdd.  54  and  55. 

*  In  reference  to  the  literature  on  this  subject  see  E.  Kulz,  Pflilger's  Arch., 
3d.  34,  and  Ludwig- Festschrift.  1891  ;  WolfEberg,  Zeitschr.  f.  Biologie,  Bd.  13, 

And  C.  Voit,  ibid. ,  Bd.  38,  S.  345. 

*  Zeitschr.  f.  Biologie,  Bd.  39. 

«  Centralbl.  f.  d.  med.  Wissensch.,  1893,  No.  11. 

•>  Pfluger's  Arch.,  Bd.  56. 

«  Zeitschr.  f.  Biologie,  Bd.  38. 


21i  TEE  LIVEB. 

dextrose  has  a  more  powerful  action  than  cane-sugar,  while  milk- 
sugar  acts  disproportionately  less  (in  rabbits  and  hens)  than  dex- 
trose, Isevulose,  cane-sugar,  and  maltose.  The  following  substances 
when  introduced  into  the  body  also  increase  the  quantity  of  glycogen 
in  the  liver:  glycerin,  gelatin,  ariutin,  and  also,  according  to  the 
investigations  of  KtJLZ,'  erythrit,  quercit,  dulcit,  mannit,  inosity 
allyl  and  crotyl  alcoJiols,  glycuronic  anhydride,  saccharic  acid, 
mucic  acid,  sodium  tartrate,  saccharin,  isosaccharin,  and  urea. 
Ammonium  carbonate,  glycocoll,  and  asparagin  may  also,  according 
to  EoHMANN",^  cause  an  increase  in  the  amount  of  glycogen  in  the 
liver.  According  to  Nebelthau^  other  ammonium  salts  and  cer- 
tain amides,  also  certain  narcotics,  hyp7iotics,  and  antipyretics,. 
produce  an  increase  in  the  glycogen  of  the  liver.  This  action  of 
the  antipyretics  (especially  antipyrin)  had  been  shown  by  Lepin"e. 
and  Porteret.* 

The  fats,  notwithstanding  the  above-mentioned  action  of  glycer- 
in, have  no  action  on  the  quantity  of  glycogen  in  the  liver,  accord- 
ing to  the  statements  of  most  investigators.  The  views  in  regard 
to  the  action  of  proteids  have  been  very  contradictory  in  the  past. 
It  is  undoubtedly  settled  from  many  observations  that  the  proteids 
also  increase  the  liver  glycogen.  Amongst  these  observations  we 
must  include  certain  feeding  experiments  with  boiled  beef 
(N'AUNT]sr)  or  blood  fibrin  (v.  Merixg),  and  especially  the  very 
careful  experiments  made  by  E.  Kulz  '  on  hens  with  pure  proteids 
such  as  casein,  seralbumin,  and  ovalbumin.  Wolffberg  °  has  also 
shown  that  a  more  abundant  accumulation  of  glycogen  takes  place 
after  feeding  with  proteids  and  carbohydrates  in  proper  proportions 
than  with  carbohydrate  food  with  only  a  little  proteid. 

MiURA ''  has  made  experiments  to  demonstrate  the  role  of  the 
inulin  as  a  glycogen-former  in  starving  rabbits.  In  certain  cases 
the  quantity  of  glycogen  was  increased,  in  others,  on  the  contrary, 
not  affected.  The  inconstancy  of  the  results  of  these  tests  may  be 
dependent  upon  the  fact  that  the  inulin  introduced  was  only  partly 

^  E.  Kulz,  Ludwig's  Festsclirift,  1891. 

2  Pfluger's  Arcb.,  Bd.  39. 

3  Zeitschr.  f .  Biologie,  Bd.  28,  S.  138. 

4  Comp.  rend.,  Tome  106,  p.  1023. 

*  Cit.  Ludwig's  Festschrift.     The  complete  literature  in  regard  to  the  gly- 
cogen formation  from  proteids  will  be  found  here, 
f  Zeitschr.  f.  Biologic,  Bd.  16,  S.  266. 
^  Ibid..  Bd.  32. 


FORMATTOX  OF  GLYCOGEN.  215 

or  only  slowly  transformed  into  lajvulose,  and  hence  the  absorbed 
sugar  could  not  always  cause  an  accumnlation  of  the  glycogen, 
MiUKA  also  mentions  the  results  of  the  older  experiments  and  also 
gives  the  older  literature. 

If  we  raise  the  question  as  to  the  action  of  the  various  bodies  in 
the  accumulation  of  glycogen  in  the  liver  we  must  call  to  mind  tliat 
a  reformation  of  glycogen  takes  place  in  this  organ,  and  also  a  con- 
sumption of  the  same.'  An  accumulation  of  glycogen  may  be 
caused  by  an  increased  formation  of  glycogen,  but  also  by  a  dimin- 
ished consumption,  or  by  both. 

We  do  not  known  how  all  the  above-mentioned  various  bodies 
act  in  this  regard.  Certain  of  them  probably  have  a  retarding  action 
on  the  transformation  of  glycogen  in  the  liver,  while  others  perhaps 
are  more  combustible  and  in  this  way  protect  the  glycogen.  Some 
probably  excite  the  livei'-cells  to  a  more  active  glycogen  formation,. 
while  others  yield  material  from  which  the  glycogen  is  formed  and 
are  glycogen-formcrs  in  the  true  sense  of  the  word.  The  knowledge 
of  these  last-mentioned  bodies  is  of  the  greatest  importance  in  the 
question  as  to  the  origin  of  glycogen  in  the  animal  body,  and  the 
chief  interest  attaches  itself  to  the  question,  to  what  extent  are  the; 
two  chief  groups  of  food,  the  proteids  and  carbohydrates,  glycogeu- 
f  ormers  ? 

The  great  importance  of  the  carbohydrates  in  the  formation  of 
glycogen  has  given  rise  to  the  opinion  that  the  glycogen  in  the  liver  is 
produced  from  other  carbohydrates  (glucose)  by  a  synthesis  in  which 
water  separates  with  the  formation  of  an  anhydride  (LrcnsiXGER 
and  others).  This  theory  [anhych'ide  theory)  has  found  opponents 
because  it  neither  explains  the  formation  of  glycogen  from  snch 
bodies  as  proteids,  carbohydrates,  gelatin,  and  others,  nor  the  cir- 
cumstance that  the  glycogen  is  always  the  same  independent  of 
the  properties  of  the  carbohydrate  introduced,  whether  it  is  dextro- 
or  Iffivo-gyrate.  It  is  therefore  the  oj)inion  of  mau}^  investigators 
that  all  glycogen  is  formed  from  proteid,  and  that  this  splits  into 
two  parts,  one  containing  nitrogen  and  the  other  free  from  nitrogen : 
the  latter  is  the  glycogen.  According  to  these  views,  the  carbo- 
hydrates act  only  in  that  they  spare  the  proteid  and  the  glycogen 
produced  therefrom  {sparing  theory  of  Weiss,  Wolffberg,  and 
others''). 

1  See  Wolffberg,  1.  c. 

'  See  WolfEberg,  1.  c,  in  regard  to  these  two  tlieories. 


216  THE  LIVER. 

Ill  opposition  to  this  view  E.  Voit/  by  feeding  experiments  with 
rice,  which  is  poor  in  nitrogen,  and  C.  Voit  "^  and  his  pupils,  by  tests 
with  dextrose,  Isevnlose,  maltose,  and  cane-sugar,  have  shown  that 
the  quantity  of  glycogen  stored  up  in  the  body,  after  partaking  of 
large  amounts  of  carbohydrates,  is  sometimes  so  large  that  it  cannot 
be  covered  by  the  proteids  decomposed  daring  the  same  time.  In 
these  cases  we  must  admit  of  glycogen  formation  from  sugars.  The 
investigations  of  0.  Yoit  show  that  dextrose  directly  or  Isevnlose 
either  directly  or  after  previous  conversion  into  dextrose  passes  into 
glycogen  in  the  liver.  Maltose  and  cane-sugar  must  first  probably 
be  transformed  into  dextrose  or  invert-sugar  in  the  intestinal  tract. 
Milk-sugar  and  galactose  seem,  according  to  Kafsch  and  Socin," 
although  contrary  to  the  observations  of  Yoit,  to  form  glycogen 
directly  if  the  absorption  in  the  intestine  is  sufiiciently  abundant. 

There  is  no  doubt  that  feeding  with  pure  proteids  leads  to  an 
accumulation  of  glycogen,  and  at  the  present  time  we  must  admit 
that  glycogen  can  be  formed  from  proteids  as  well  as  from  carbo- 
hydrates. 

The  manner  in  which  glycogen  is  formed  from  proteids  is  not 
known.  The  view  held  by  certain  investigators  that  carbohydrates 
split  off  directly  from  the  genuine  proteids  has  not  sufficient  basis, 
and  therefore  the  glycogen  formation  is  often  explained  according 
to  Pfluger,^  by  a  synthesis  from  the  proteids  after  a  complex 
cleavage. 

Like  the  carbohydrates  in  general,  so  has  glycogen  without  any 
doubt  a  great  importance  in  the  formation  of  heat  and  development 
of  energy  in  the  animal  body.  The  possibility  of  the  formation  of 
fat  from  glycogen  must  not  be  denied.  Glycogen  is  generally  con- 
sidered as  accumulated  reserve  food  in  the  liver  and  formed  in  the 
liver-cells.  Where  does  the  glycogen  existing  in  the  other  organs, 
such  as  the  muscles,  originate?  Is  the  glycogen  of  the  muscles 
formed  on  the  spot  or  is  it  transmitted  to  the  muscles  by  the  blood  ? 
These  questions  cannot  yet  be  answered  with  positiveness,  and  the 
investigations  on  this  subject  by  different  experimenters "  have 
given  contradictory  results.     The  later  experiments  of  Kulz,°  in 

I  Zeitschr.  f.  Biologie,  Bd.  35,  S.  543. 

3  Arcli.  f.  exp.  Path.  u.  Pharm.,  Bd.  31. 

■»  Pfiilger's  Arch.,  Bd.  42. 

5  See  Minkowski  and  Laves,  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  23. 

«  Zeitschr.  f.  Biologie,  Bd.  27. 


FORMATION  OF  SUGAR  IN  TUB  LIVER.  21 7 

which  he  studied  the  glycogen  formatiou  by  passing  blood  contain- 
ing cane-sugar  tlirough  the  muscle,  has  led  to  no  conclusive  results. 

If  we  consider  that  the  blood  and  lymph  contain  a  diastatic 
enzyme  which  transforms  glycogen  into  dextrose,  and  also  that  the 
glycogen  regularly  occurs  in  the  form-elements  and  is  not  dissolved  in 
the  fluids,  it  seems  probable  that  the  glycogen  is  not  transmitted  by 
the  blood  to  the  organs  in  solution,  but  perhaps  more  likely,  if  the 
leucocytes  do  not  act  as  carriers,  is  formed  on  the  spot  from  the 
dextrose.  The  glycogen  formation  seems  to  be  a  general  function 
of  the  cells.  In  adults  the  liver,  which  is  very  rich  in  cells,  has  the 
property,  on  account  of  its  anatomical  position,  of  transforming 
large  quantities  of  dextrose  into  glycogen. 

The  question  now  arises  whether  there  is  any  foundation  for  the 
statement  that  the  liver  glycogen  is  transformed  into  dextrose. 

As  first  shown  by  Bernard  and  repeated  by  many  investigators, 
the  glycogen  in  a  dead  liver  is  gradually  changed  into  dextrose,  and 
this  sugar  formation  is  caused,  as  Bernard  supposed  and  Arthus 
and  HuBER '  proved,  by  a  diastatic  enzyme.  This  post-mortem 
sugar  formation  led  Bernard  to  tlie  assumption  of  the  formation 
of  sugar  from  glycogen  in  the  liver  during  life.  Bernard  '"'  sug- 
gested the  following  arguments  for  this  theory:  The  liver  always 
contains  some  sugar  under  physiological  conditions,  and  the  blood 
from  the  hepatic  vein  is  always  somewhat  richer  in  sugar  than  the 
blood  from  the  portal  vein.  The  correctness  of  either  or  both  of 
these  statements  has  been  disputed  by  many  investigators.  Pavy, 
Ritter,  Sciiiff,  Eulenberg,  Lussana,  Abeles,  and  others  deny 
the  occurrence  of  dextrose  in  the  .liver  during  life,  and  also  the 
greater  amount  of  dextrose  in  the  blood  from  the  hepatic  vein  is 
disclaimed  by  them  and  certain  otlier  investigators.  A  few  inves- 
tigators claim  that  a  greater  amount  of  sugar  may  occur  in  the 
hepatic  vein  under  certain  circumstances,  and  they  consider  in  these 
cases  that  it  is  caused  by  the  operation. 

The  doctrine  as  to  the  physiological  formation  of  sugar  in  the 
liver  has  obtained  an  energetic  advocate  in  Seegen.'  He  main- 
tains, after  numerous  experiments,  that  the  liver  regularly  contains 

'  Arch,  de  physiol.,  (5)  Tome  4. 

'  In  regard  to  the  literature  oa  sugar  formation  in  the  liver  see  Bernard, 
Lemons  sur  le  diab^te.  Paris,  1877.  Seegen,  Die  Zuckerbilduug  im  Thierkorper. 
Berlin,  1890.     M.  Bial,  Pfliiger's  Arch.,  Bd.  55,  S.  434. 

^  See  Seegen,  Die  Zuckerbildung  im  Thierkorper.    Berlin,  1890. 


218  THE  LIVER. 

considerable  amonnts  of  sugar.  He  has  observed  an  increase  of  3^ 
in  the  quantity  of  dextrose  in  the  liver  of  a  dog  kept  alive  by  pass- 
ing arterial  blood  through  the  organ,  and  lastly  he  has  also  found  in 
a  very  great  number  of  experiments  on  dogs  that  the  blood  from 
the  hepatic  vein  always  contains  more — even  double  as  much — sugar 
than  the  blood  from  the  portal  vein. 

Although  Seegeist  energetically  espouses  the  doctrine  of  Ber- 
i^AED  as  to  the  vital  sugar  formation  in  the  liver,  still  it  deviates 
essentially  from  Bernaed  in  that  he  claims  the  dextrose  is  not 
derived  from  the  glycogen.  According  to  Seegei^  the  sugar  is 
formed  from  peptones  and  fat.  The  observations  on  which  he 
bases  this  view  seem  hardly  to  be  correct,^  according  to  the  control 
experiments  made  by  many  investigators.  The  statement  of 
Lepike  ^  as  to  the  occurrence  of  an  enzyme  in  the  blood  which  has 
the  property  of  transforming  peptone  into  sugar  could  not  be  sub- 
stantiated by  BiAL. 

The  circumstance  that  the  blood-sugar  rapidly  sinks  to  ^-^  of 
its  original  quantity,  or  even  disappears  when  the  liver  is  cut  out  of 
the  circulation,  speaks  for  a  vital  formation  of  sugar  in  the  liver 
(Seegen,  Bock,  and  Hoffmann").  In  geese  whose  livers  were 
removed  from  the  circulation  Minkowski  ^  found  no  sugar  in  the 
blood  after  a  few  hours.  We  will  also  learn  shortly  of  certain 
poisons  and  operative  changes  which  may  cause  an  abundant  elimi- 
nation of  sugar,  but  only  when  the  liver  contains  glycogen.  If  we 
recall  the  fact  shown  by  Eohmann  and  Bial  ^  that  the  lymph  as 
well  as  the  blood  contains  a  diastatic  enzyme,  then  several  reasons 
speak  for  the  view  of  Bernard  that  the  post-mortem  formation  of 
sugar  from  the  glycogen  in  the  liver  is  a  continuation  of  the  vital 
process.  Although  it  is  unanimous  that  the  post-mortem  sugar 
formation  is  produced  by  a  diastatic  enzyme,  still  several  investiga- 
tors, such  as  Dastre  and  ISToel-Paton,"  are  of  the  view  that  sugar 
formation  is  not  caused  in  life  by  an  enzyme,  but  by  a  vital  process 
of  the  cell  protoplasm. 

'  A  compilation  of  these  control  experiments  may  be  found  in  Bial,  Pflil- 
ger's  Arcli. ,  Bd.  55. 

^  Compt.  rend.,  Tome  115  and  116. 
3  See  Seegen,  1.  c,  pp.  182-184. 

*  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  21. 
^  See  pp.  124  and  181,  this  book. 

*  See  Noel-Paton,  On  Hepatic  Glycogenesis.  Phil.  Trans,  of  the  Eoy. 
Soc.  London,  vol.  185,  B.  1894. 


QLTCOSURIA.  219 

The  relationship  of  the  sugar  eliminated  in  the  nrine  under 
certain  conditions,  such  as  in  diabetes  mellitus,  certain  intoxications, 
lesions  of  the  nervous  system,  etc.,  to  the  glycogen  of  the  liver  is 
also  an  important  question. 

It  does  not  enter  into  the  plan  and  scope  of  this  book  to  enter 
into  detail  into  the  various  views  in  regard  to  glycosuria  and 
diabetes.  The  appearance  of  dextrose  in  the  urine  is  a  symptom 
which  may  have  essentially  different  causes,  depending  upon  dif- 
ferent circumstances.  Only  a  few  of  the  most  important  points  will 
be  mentioned. 

The  blood  contains  always  about  an  average  of  1.5  p.  m.,  while 
the  urine  at  most  contains  only  traces.  When  the  quantity  of 
sugar  in  the  blood  rises  to  3  p.  m.  or  above,  then  sugar  passes  into 
the  urine.  The  kidneys  have  the  property  to  a  certain  extent  of 
preventing  the  passage  of  blood-sugar  into  the  urine;  and  it  follows 
from  this  that  an  elimiuation  of  sugar  in  the  urine  may  be  caused 
partly  by  a  reduction  or  suppression  of  this  above-mentioned  activity 
and  partly  also  by  an  abnormal  increase  of  the  quantity  of  sugar  in 
the  blood. 

The  first  seems,  according  to  v.  Merixg  and  Minkowski,  to 
be  the  case  in  phlorhizin  *  diabetes.  Y.  Mering  has  found  that  a 
strong  glycosuria  appears  in  man  and  animals  on  the  administration 
of  the  glucoside  phlorhizin,  and  that  the  quantity  of  sugar  in  the 
blood  is  not  increased,  but  somewhat  diminished.  In  this  form  of 
diabetes  we  have,  according  to  Minkowski,  abnormal  processes  in 
the  kidneys.  According  to  Levene^  phlorhizin  diabetes  is  not 
produced  by  an  increased  elimination  of  sugar  by  the  kidneys,  but 
more  likely  an  increased  formation  of  sugar  in  tliese  organs.  He 
found  generally  more  sugar  in  the  venous  blood  of  the  kidneys  than 
in  the  arterial  blood,  and  he  also  found  considerably  more  sugar 
after  injection  of  phlorhizin  than  under  normal  conditions.  He 
agrees  with  the  observations  of  other  investigators  such  as  Praus- 
NiTZ,  Cremer,  and  Kitter,  that  in  phlorhizin  diabetes  the  sugar 
is  formed  from  the  protein  substances.     All  other  forms  of  glycu- 

'  In  regard  to  the  literature  on  plilorhizin  diabetes  see  :  v.  Mering,  Zeitsclir. 
f.  kliu.  Med.,  Bdd.  14  and  16;  Minkowski,  Berl.  klin.  Wocbenschr.,  1893. 
No.  5,  and  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  31;  Moritz  and  Prausnitz, 
Zeitschr.  f.  Biologie.,  Bdd.  37  and  39;  Kiilz  and  Wright,  ibid.,  Bd.  37,  S.  181; 
Cremer  and  Ritter,  ihid.,  Bdd.  38  and  89. 

«  Journal  of  Physiol.,  Vol.  17. 


220  THE  LIVER. 

soria  or  diabetes  depend,  on  the  contrary,  as  far  as  known,  to  an 
increased  quantity  of  sugar  in  the  blood,  namely,  a  hyperghiccemia. 

A  hyperglacaemia  may  be  caused  in  various  ways.  It  may  be 
caused,  for  example,  by  the  introduction  of  more  sugar  than  the 
body  can  destroy. 

The  property  of  the  animal  body  to  assimilate  the  different 
varieties  of  sugar  has  naturally  a  limit.  If  too  much  sugar  is  intro- 
duced into  the  intestinal  tract  at  one  time,  so  that  the  so-called 
assimilation  limit  (see  Chapter  XIX  on  absorption)  is  overreached, 
then  the  excess  of  absorbed  sugar  passes  into  the  urine.  This  form 
of  glycosuria  is  called  alimentary  glycosuria,^  and  it  is  caused  by  the 
passage  of  more  sugar  into  the  blood  than  the  liver  and  other  organs 
can  destroy. 

As  the  liver  cannot  transform  all  the  sugar  into  glycogen  which 
comes  to  it  in  alimentary  glycosuria,  it  is  possible  that  a  glycosuria 
may  be  brought  about  by  the  activity  of  the  liver  to  transform  sugar 
into  glycogen  being  changed  or  reduced  by  disease.  It  is  difficult 
to  state  in  how  far  such  a  glycosuria  occurs,  but  according  to 
Seegen"  the  lighter  forms  of  diabetes  are  produced  in  this  way. 

We  differentiate  between  light  and  severe  forms  of  diabetes. 
In  the  first  the  urine  only  contains  sugar  when  carbohydrates  are 
taken  as  food,  while  in  the  other  case  the  urine  contains  sugar  even 
with  food  entirely  free  from  carbohydrates.  According  to  the  view 
of  Seegen,^  in  light  forms  of  diabetes  the  liver  is  incapable  of 
transforming  all  the  carbohydrates  introduced  into  glycogen,  or  to 
utilize  this  in  a  proper  way,  and  the  activity  of  the  liver-cells  is  also 
reduced  or  changed  in  these  cases.  This  view  is  nevertheless  hardly 
based  on  sufficient  proof. 

A  hyperglucaBuiia,  which  passes  into  a  glycosuria,  may  also  be 
brought  about  by  an  excessive  formation  of  sugar  from  the  glycogen 
within  the  animal  body. 

The  so-called  ^tg-w re,  and  also  probably  those  glycosurias  which 
occur  after  other  lesions  of  the  nervous  system,  belong  to  the  above 
group  of  glycosurias.  The  glycosuria  produced  on  poisoning  with 
carbon  monoxide,  curare,  strychnin,  morphin,  etc.,  also  belong 
to  this  group.  That  the  glycosuria  produced  in  these  cases  is  due 
to  an  increased  transformation  of  the  glycogen  follows  from  the 
fact  that  no  glycosuria  appears,  under  the  above-mentioned  circum- 

1  See  Moritz,  Arch.  f.  klin.  Med.,  Bd.  46,  1890. 
'  Die  Zuckerbildune:.  etc.     Lecture  15. 


DIABETES.  221 

stances,  when  the  liver  has  been  jirevionsly  made  free  from  glycogen 
by  starvation  or  other  means.' 

A  hyperglncagniia  with  glycosuria  may  also  be  caused  by  a  de- 
creased activity  of  the  animal  body  to  consume  or  destroy  the  sugar. 
In  this  case  the  sugar  must  accumulate  in  tlie  blood,  and  the  forma- 
tion of  diabetes  mellitus  is  now  generally  explained  by  this  process. 

The  inability  of  diabetics  to  destroy  or  consume  the  sugar  does 
not  seem  to  be  connected  with  any  decrease  in  the  oxidation  energy 
of  the  cells,  as  both  varieties  of  sugar,  dextrose  and  lasvulose,  both 
of  which  can  be  oxidized  with  the  same  readiness,  act  differently  in 
the  body  of  diabetics.  Lgevulose  is,  according  to  Kulz  ^  and  other 
investigators,  contrary  to  dextrose,  utilized  to  a  great  extent  in  the 
organism,  and  may  even  cause  a  deposit  of  glycogen  in  the  liver  in 
animals  with  pancreas-diabetes  (Minkowski^).  In  this  diabetes 
the  ability  of  the  cells  to  utilize  the  dextrose  is  diminished,  and  this 
diminution  of  ability  seems  to  be  in  some  way  dependent  upon  the 
pancreas.  The  investigations  of  Minkowski,  v.  Mering,  Dome- 
Nicis,  and  later  by  other  investigators '  have  shown  that  a  true 
diabetes  of  a  severe  kind  is  caused  by  the  total  extirpation  of  the 
pancreas  of  many  animals,  especially  dogs.  As  in  man  in  severe 
forms  of  diabetes,  so  also  in  dogs  with  pancreas-diabetes  an  abundant 
elimination  of  sugar  takes  place  even  on  the  complete  exclusion  of 
carbohydrates  in  the  food,  and  the  formation  of  sugar  in  these  cases 
is  derived  from  the  protein  substances.  It  seems  in  man  with 
diabetes  that  the  ability  of  the  sugar  destruction  is  never  quite 
arrested ;  in  dogs  with  pancreas-diabetes  Minkowski  and  v.  Mee- 
ING,  as  also  Hedon,^  have  been  able,  in  a  few  cases,  to  detect  that 
the  total  quantity  of  sugar  introduced  with  the  food  passed  into 
the  urine. 


'  See  Bock,  Pfltiger's  Arch.,  Bd.  5;  Bock  and  Hoffmann,  Espt.  Studien 
Uber  Diabetes  (Berlin,  1874).  CI.  Bernard,  Le9ons  sur  le  diabete  (Paris); 
T.  Araki,  Zeitscbr.  f.  pbysiol.  Chem.,  Bd.  15,  S.  351. 

"  Beitrage  zur  Path,  und  Ther.  des  Diabetes  mellitus  Marburg,  1874. 

2  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  31. 

*  See  Minkowski,  Untesuchrungen  iiber  Diabetes  mellitus  nach  Exstirpa- 
tion  des  Pankreas  (Leipzig,  1893),  and  the  chapter  on  diabetes  in  v.  Noorden's 
Lehrbuch  der  Path,  des  StofEwechsels  (Berlin,  1893),  which  contains  a  very 
copious  index  of  the  literature.  In  regard  to  diabetes  see  also  CI.  Bernard,  Lemons 
sur  le  diabete  (Paris),  and  Seegen,  Die  Zuckerbilduug  im  Thierkorper  (Berlin, 
1890). 

*  Arch,  de  Physiol.,  (5)  Tome  5. 


222  THE  LIVER. 

Artificial  pancreas-diabetes  may  also  in  other  respects  present 
exactly  the  same  picture  as  diabetes  in  man;  and  as  in  the  past  we 
have  always  looked  to  the  liver  for  the  cause  of  diabetes,  our  atten- 
tion is  now  more  and  more  called  to  the  pancreas.  We  do  not 
know  in  what  respect  the  pancreas '  stands  to  diabetes.  We  will 
refer  to  this  question  again  in  a  subsequent  chapter  (Chapter  IX). 

The  Bile  and  its  Formation. 

By  the  establishment  of  a  biliary  fistula,  an  operation  which  was 
first  performed  by  Schwanjst  '  in  1844  and  which  has  been  improved 
lately  by  Dastre,^  it  is  possible  to  study  the  secretion  of  the  bile. 
This  secretion  is  continuous,  but  with  varying  intensity.  It  takes 
place  under  a  very  low  pressure ;  therefore  an  apparently  unimpor- 
tant hindrance  in  the  outflow  of  the  bile,  namely,  a  stoppage  of 
mucus  in  the  exit  of  the  secretion  of  large  quantities  of  viscous  bile, 
may  cause  stagnation  and  absorption  of  the  bile  by  means  of  the 
lymphatic  vessels  (absorption  icterus). 

The  quantity  of  bile  secreted  in  the  24  hours  in  dogs  can  be 
exactly  determined.  The  quantity  secreted  by  different  animals 
varies,  and  the  limits  are  2.9-36.4  gm.  bile  per  kilo  of  weight  in  the 
24  hours.'' 

The  statements  aS  to  the  extent  of  bile  secretion  in  man  are  few 
and  not  to  be  depended  on.  Raitke  *  found  (using  a  method  which 
is  not  free  from  criticism)  a  secretion  of  14  gm.  bile  with  0.44  gm. 
solids  per  kilo  in  24  hours.  Noel-Paton  °  observed  a  51-year-old 
woman  with  biliary  fistula  for  23  days,  and  found  an  average  of  638 
cc.  with  8.378  gm.  solids  in  24  hours.  MAfo-RoBSOK,*  whose 
observations  on  a  woman  42  years  old  with  biliary  fistula  extended 
over  15  months,  found  an  average  of  862  cc.  for  the  24  hours'  bile 
secretion.     The  aijthor  '  found  650  cc.  as  the  maximum  quantity 

1  Arch.  f.  Anat.  und  Physiol.,  1844. 

2  Arch,  de  Physiol.,  Tome  22. 

*  In  regard  to  the  quantity  of  bile  secreted  in  animals  see  Heidenhain,  Die 
Gallenahsonderung'  m  Hermanns  Handbuch  der  Physiol.,  Bd.  5,  and  Stadel- 
mann,   Der  Icterus  unci  seine  verschiedenen  Formen  (Stuttgart,  1891). 

*  Die  BluivertheJlung  und  der  Thatigkeitswechsel  der  Organe.  Leipzig, 
1871. 

5  Rep.  Lab.  Roy.  Coll.  Phys.  Edinb.,  Vol.  3, 

»  Proc.  Roy.  Soc,  Vol.  47. 

T  Nova  Acta  Reg.  Soc.  Scient.  Upsala,  Ser.  3,  Vol  16,  1893. 


BILE.  223 

in  a  man  and  950  cc.  in  a  woman.  Such  determinations  are  of 
doabtf ul  value,  because  in  most  cases  it  follows  from  the  composition 
of  the  collected  bile  that  we  are  not  dealing  with  a  secretion  of 
normal  liver-bile. 

The  quantity  of  bile  secreted  is,  however,  as  specially  shown  by 
Stadelmanx,'  subject  to  such  great  variation  even  under  physio- 
logical conditions  that  the  study  of  these  circumstances  which  influ- 
ence the  secretion  is  very  difficult  and  uncertain.  The  contradic- 
tory statements  by  different  investigators  may  probably  be  explained 
by  this  fact. 

In  starvation  the  secretion  diminishes.  According  to  Luk- 
JANOAV*  and  Albertoni,'  under  these  conditions  the  absolute 
quantity  of  solids  decreases,  while  the  relative  quantity  increases. 
After  partaking  of  food  the  secretion  increases  again.  The  state- 
ments are  contradictory  in  regard  to  the  time  -necessary  after  par- 
taking of  food  before  the  secretion  reaches  its  maximum.  After  a 
careful  examination  and  compilation  of  all  the  existing  statements 
Heidenhaix  ^  has  come  to  the  conclusion  that  in  dogs  the  curve  of 
rapidity  of  secretion  shows  two  maxima,  the  first  at  the  3d  to  5th 
hour,  and  the  second  at  the  13tli  to  15th  hour,  after  partaking  of 
food. 

According  to  the  older  statements,  the  proteids,  of  all  the  differ- 
ent foods,  cause  the  greatest  secretion  of  bile,  while  the  carbohy- 
drates diminish,  or  at  least  excite  much  less  than  the  proteids. 

It  is  nevertheless  j)ositive  that  an  increase  in  the  bile  secretion 
takes  place  after  a  continuous  over-abundant  meat  diet.  We  are  by 
no  means  agreed  as  to  the  action  of  the  fats.  While  many  older 
investigators  have  not  observed  any  increase,  but  rather  the  reverse, 
in  the  secretion  of  bile  after  feeding  with  fats,  the  newer  exj)eri- 
ments  made  by  Rosenberg  ^show  that  the  fats  have  a  more  power- 
ful exciting  action  on  the  secretion  of  bile  than  the  other  foods, 
and  that  olive-oil  is  a  strong  cholagogue.  This  statement  seems, 
according  to  the  investigations  of  MANDELSTAMii,°  not  to  be  suffi- 
ciently proven. 

'  Der  Icterus. 

»  Zeitsclir.  f.  pliysiol.  Chem.,  Bd.  16. 

*  Recherches  sur  la  secretion  biliaire.     Turin,  1893. 

•*  Hermann's  Handb. ,  Bd.  5,  and  Stadelmann,  Der  Icterus. 
5  Pfliiger's  Arch.,  Bd.  46. 

*  Ueber  denEinfluss  einiger  Arzneiinittel  auf  Sekretion  und  Zusammensetz- 
ung  der    Galle.  Dissert.  Dorpat,  1890.     In  regard  to  the  action  of  various  foods 


224:  TEE  LIVER. 

The  question  whether  there  exist  special  medicinal  bodies, 
so-called  cholagogues,  which  have  a  specific  exciting  action  on  the 
secretion  of  bile  has  been  answered  in  very  different  ways.  Many, 
especially  the  older  investigators,  have  observed  an  increase  in  the 
bile  secretion  after  the  use  of  certain  therapeutic  agents  such  as 
calomel,  rhubarb,  jalap,  turpentine,  olive-oil,  sodium  salicylate, 
etc.,  while  others,  especially  the  later  investigators,  have  arrived  at 
quite  opposite  results.  From  all  appearances  this  contradiction  is 
due  to  the  great  irregularity  of  the  normal  secretion,  which  may  be 
readily  mistaken  in  tests  with  therapeutic  agents. 

Schiff's'  view,  that  the  bile  absorbed  from  the  intestinal  canal 
increases  the  secretion  of  bile  and  hence  acts  as  a  cholagogue,  seems 
to  be  a  positively  proven  fact  by  the  investigations  of  several  experi- 
menters. ° 

The  bile  is  a  mixture  of  the  secretion  of  the  liver-cells  and  the 
so-called  mucus  which  is  secreted  by  the  glands  of  the  biliary 
passages  and  by  the  mucous  membrane  of  the  gall-bladder.  The 
secretion  of  the  liver,  which  is  generally  poorer  in  solids  than  the 
bile  from  the  gall-bladder,  is  thin  and  clear,  while  the  bile  collected 
in  the  gall-bladder  is  more  ropy  and  viscous  on  account  of  the 
absorption  of  water  and  the  admixture  of  "  mucus,"  and  cloudy 
because  of  the  admixture  of  cells,  pigments,  and  the  like.  The 
specific  gravity  of  the  bile  from  the  gall-bladder  varies  considerably, 
being-in  man  between  1.010  and  1.040.  Its  reaction  is  alkaline.  The 
color  changes  in  different  animals  r  golden  yellow,  yellowish  brown, 
olive-brown,  brownish  green,  grass-green,  or  bluish  green.  Bile 
obtained  from  an  executed  person  immediately  after  death  is  golden 
yellow  or  yellow  with  a  shade  of  brown.  Still  cases  occur  in  which 
fresh  human  bile  has  a  green  color.  The  ordinary  post-mortem  bile 
has  a  variable  color.  The  bile  of  certain  animals  has  a  peculiar 
odor;  as  example,  ox-bile  has  an  odor  of  musk,  especially  on  warm- 
ing. The  taste  of  bile  is  also  different  in  different  animals.  Human 
as  well  as  ox  bile  has  a  bitter  taste  with  a  sweetish  after-taste.     The 


on  the  secretion  of  bile  see  Heidenhain  in  Hermann's  Handbuch,  etc.,  and 
Stadelmann,  Der  Icterus. 

1  Pfliiger's  Arch.,  Bd.  3. 

*  See  Stadelmann,  Der  Icterus,  and  tlie  dissertations  of  bis  pupils,  namely, 
Winteler,  Expt.  Beitrage  zur  Frage  des  Kreislaufes  der  Qalle  (Inaug  Diss. 
Dorpat,  1892),  and  Gertner,  Expt.  Beitrage  zur  Physiol,  und  Path,  der  Gallen- 
sekretion"  (Inaug.  Diss.  Jurjew,  1893). 


BILE  SALTS.  225 

"bile  of  the  pig  and  rabbit  has  an  intense  persistent  bitter  taste.  On 
heating  bile  to  boiling  it  does  not  coagulate.  It  contains  (in  the 
ox)  only  traces  of  trne  mncin,  and  its  ropy  properties  dejiend,  it 
seems,  chiefly  on  the  presence  of  a  nucleoalbumiu  similar  to  mucin 
(Paijkull  ').  The  author  '  has,  on  the  contrary,  found  true  mucin 
in  human  bile.  The  specific  constituents  of  the  bile  are  hile-acids 
combined  with  alkalies,  bile-pigj)ients,  and  besides  small  quantities 
of  lecithin,  cholesterin,  soa2)s,  neutral  fats,  urea,  and  mineral  sub- 
stances, chiefly  sodium  chloride,  calcium,  and  magnesium  phos- 
phate, and  iron.     Traces  of  copper  also  occur. 

Bile  Salts.  The  thus-far  best  studied  bile-acids  may  be  divided 
into  two  groups,  the  glycocholic  and  taurocliolic  acid  groups.  As 
found  by  the  author,^  a  third  group  of  bile-acids  occur  in  the  shark 
and  probably  also  in  other  animals.  They  are  rich  in  sulphur,  and 
like  the  ethereal  sulphuric  acids  they  split  off  sulphuric  acid  on 
boiling  with  hydrochloric  acid.  All  glycocholic  acids  contain 
nitrogen,  but  are  free  from  sulphur  and  can  be  split  with  the  addi- 
tion of  water  into  glycocoll  (amido-acetic  acid)  and  a  nitrogen-free 
acid,  cholalic  acid.  All  taurocliolic  acids  contain  nitrogen  and 
sulphur  and  are  split,  with  the  addition  of  water,  into  taurin 
(amido-ethylsulphonic  acid)  and  cholalic  acid.  The  reason  of  the 
existence  of  different  glycocholic  and  taurocliolic  acids  depends  on 
the  fact  that  there  are  several  cholalic  acids. 

The  different  bile-acids  occur  in  the  bile  as  alkali  salts,  generally 
in  combination  with  sodium,  but  in  sea-fishes  as  potassium  salts. 
In  the  bile  of  certain  animals  we  find  almost  solely  glycocholic  acid, 
in  others  only  taurocholic  acid,  and  in  other  animals  a  mixture  of 
both  (see  below). 

All  alkali  salts  of  the  biliary  acids  are  soluble  in  water  and 
alcohol,  but  insoluble  in  ether.  Their  solution  in  alcohol  is  there- 
fore precipitated  by  ether,  and  this  precipitate,  with  the  proper 
care  in  manipulation,  gives,  for  nearly  all  kinds  of  bile  thus  far 
investigated,  rosettes  or  balls  of  fine  needles  or  4-6-sided  prisms 
(Plattner's  crystallized  bile).  Fresh  human  bile  also  crystallizes 
readily.  The  bile-acids  and  their  salts  are  optically  active  and 
dextrorotatory.  The  former  are  dissolved  by  concentrated  sul- 
phuric acid  at  the  ordinary  temperature,  forming  a  reddish-yellow 

'  Zeitschr.  f.  pbysiol.  Chem.,  Bd.  13. 

'  Nova  Acta  reg.  soc.  scient.   TJpsala,  Ser.  3,  Vol.  16. 

'  Investigation  not  published. 


226  THE  LIVER. 

liquid  which  lias  a  beautiful  green  fluorescence.  On  carefall}^ 
warming  with  concentrated  sulphuric  acid  and  a  little  cane-sugar, 
the  bile-acids  give  a  beautiful  cherry-red  or  reddish- violet  liquid. 
PETTEJ^iTKOFER's  reaction  for  bile-acids  is  based  ou  this  behavior. 

Pettenkofper's  test  for  bile-acids  is  performed  as  follows:  A 
small  quantity  of  bile  in  substance  is  dissolved  in  a  small  porcelain 
dish  in  concentrated  sulphuric  acid  and  warmed,  or  some  of  the 
liquid  containing  the  bile-acids  is  mixed  with  concentrated  sul- 
phuric acid,  taking  special  care  in  both  cases  that  the  temperature 
does  not  rise  higher  than  60-70°  0,  Then  a  10^  solution  of  cane- 
sugar  is  added,  drop  by  drop,  continually  stirring  with  a  glass  rod. 
The  presence  of  bile  is  indicated  by  the  production  of  a  beautiful 
red  liquid,  whose  color  does  not  disappear  at  the  ordinary  tempera- 
ture, but  becomes  more  bluish  violet  in  the  course  of  a  day.  This 
red  liquid  shows  a  spectrum  with  two  absorption-bands,  the  one  at 
^  and  the  other  between  D  and  ^,  near  E. 

This  extremely  delicate  test  fails,  however,  when  the  solution  is 
heated  too  high  or  if  an  improper  quantity — generally  too  mnch — 
of  the  sugar  is  added.  In  the  last-mentioned  case  the  sugar  easily 
Carbonizes  and  the  test  becomes  brown  or  dark  brown.  The  reac- 
tion readily  fails  if  the  sulphuric  acid  contains  sulphurous  acid  or 
the  loAver  oxides  of  nitrogen.  Many  other  substances,  such  as  pro- 
teids,  oleic  acid,  amyl  alcohol,  morphin,  and  others,  give  a  similar 
reaction,  and  therefore  in  doubtful  cases  the  spectroscopic  examina- 
tion of  the  red  solution  must  not  be  forgotten. 

Pettenkofer's  test  for  the  bile-acids  depends  essentially  on  the 
fact  that  furfurol  is  formed  from  the  sugar  by  the  sulphuric  acid, 
and  this  body  can  therefore  be  substituted  for  the  sugar  in  this  test 
(Mylius).  According  to  Mtlius  '  and  v.  Udranszky  ^  a  1  p.  m. 
solution  of  f  nrf  arol  should  be  used.  Dissolve  the  bile,  which  must 
first  be  purified  by  animal  charcoal,  in  alcohol.  To  each  c.  c.  of 
alcoholic  solution  of  bile  i-n  a  test-tube  add  1  drop  of  the  furfurol 
solution  and  1  c.  c.  cone,  salphuric  acid,  and  cool  when  necessary 
so  that  the  test  does  not  become  too  warm.  This  reaction,  when 
performed  as  described,  will  detect  ^V~to  milligram  cholalic  acid 
(v.  Udranszky).  Other  modifications  of  Pettenkofer's  test 
have  been  proposed. 

Glycocholic  Acid.     The  constitution  of  that  glycocholic  acid, 

1  Zeitschr.  f.  pliysiol.  Chem.,  Bd.  11,  S.  492, 
•>  Ibid.,  Bd.  13,  S.  370. 


BILE  ACIDS.  227 

occurring  in  hnman  aud  ox  bile,  which  has  been  most  studied  is 
represented  by  the  formula  C^^lI^gNOg.  Glycocholic  acid  is  absent 
or  nearly  so  in  the  bile  of  carnivora.  On  boiling  with  acids  or 
alkalies  this  acid,  which  is  analogous  to  hippuric  acid,  is  converted 
into  cholalic  acid  and  glycocoll. 

Glycocholic  acid  crystallizes  in  fine,  colorless  needles  or  prisms. 
It  is  soluble  with  difficulty  in  water  (in  about  300  parts  cold  and 
120  parts  boiling  water),  and  is  easily  precipitated  from  its  alkali- 
salt  solution  by  the  addition  of  dilute  mineral  acids.  It  is  readily 
soluble  in  strong  alcohol,  but  with  great  difficulty  in  ether.  The 
solutions  have  a  bitter  but  at  the  same  time  sweetish  taste.  The 
salts  of  the  alkalies  and  alkaline  earths  are  soluble  in  alcohol  and 
water.  The  salts  of  the  heavy  metals  are  mostly  insoluble  or 
soluble  with  difficulty  in  water.  The  solution  of  the  alkali  salts  in 
water  is  precipitated  by  sugar  of  lead,  copper-oxide  and  ferric  salts, 
and  silver  nitrate. 

The  preparation  of  pure  glycocholic  acid  may  be  performed  in 
several  ways.  We  may  precipitate  the  bile,  which  has  been  freed 
from  mucus  by  means  of  alcohol  and  the  alcohol  removed  by  evap- 
oration, by  a  solution  of  lead  acetate.  The  precipitate  is  then 
decomposed  by  a  soda  solution  and  heat,  evaporated  to  dryness,  and 
the  residue  extracted  with  alcohol,  which  dissolves  the  alkali  glyco- 
cholate.  The  alcohol  is  distilled  from  the  filtered  solution  and  the 
residue  dissolved  in  water;  this  solution  is  now  decolorized  by 
animal  charcoal,  and  the  glycocholic  acid  precipitated  from  the 
solution  by  the  addition  of  a  dilute  mineral  acid.  The  acid  may  be 
obtained  in  crystals  either  from  boiling  water,  on  cooling,  or  from 
strong  alcohol  by  the  addition  of  ether.  The  reader  is  referred  to 
more  exhaustive  works  for  other  methods  of  prejjaration. 

Hyo-glycocliolic  Acid,  C27H43NOS,  is  tlie  crystalline  glycocholic  acid  obtained 
from  the  bile  of  the  pig.  It  is  very  insoluble  in  water.  The  alkali  salts,  ":vhose 
solutions  have  an  intense  bitter  taste  without  any  sweetish  after-taste,  are  pre- 
cipitated by  CaCla,  BaClj,  and  MgCla,  and  may  be  salted  out  like  a  soap  by 
NaaS04  when  added  in  sufficient  quantity.  Besides  this  acid  there  occurs  in 
the  bile  of  the  pig  still  another  glycocholic  acid  (JoLix'j. 

The  glycocholate  in  the  bile  of  the  rodent  is  also  precipitated  by  the  above- 
mentioned  salts,  but  cannot,  like  the  corresponding  salt  in  the  human  or  ox 
bile,  be  precipitated  on  saturating  with  a  neutral  salt  (XaaS04),  Guano  bile- 
acid  possibly  belongs  to  the  glycocholic-acid  group,  and  is  found  in  Peruvian 
guano  but  has  not  been  thoroughly  studied. 

Taurocholic  Acid.     This  acid,  which  is  found  in   the  bile  of 
man,  carnivora,  oxen  and  a  few  other  herbivora,  such  as  sheep  and 
'  Zeitschr.  f,  physiol.  Chem.,  Bdd.  12  and  13. 


228  THE  LIVER. 

goats,  has  the  constitntion  Cj^H^^NSO,.     On  boiling  with  acids  and 
alkalies  it  splits  into  cholalic  acid  and  taurin. 

Tanrocholic  acid  may  be  obtained,  though  only  with  difficulty, 
in  fine  needles  which  deliquesce  in  the  air  (Paeke  ').  It  is  very 
soluble  in  water,  and  can  hold  the  difficultly  soluble  glycocholio 
acid  in  solution.  This  is  the  reason  why  a  mixture  of  glycocholate 
with  a  sufficient  quantity  of  taurocholate,  which  often  occurs  in 
ox-bile,  is  not  precipitated  by  a  dilute  acid.  Taurocholic  acid  is 
readily  soluble  in  alcohol,  but  insoluble  in  ether.  Its  solntions  have 
a  bitter-sweet  taste.  Its  salts  are,  as  a  rule,  readily  soluble  in 
water,  and  the  solutions  of  the  alkali  salts  are  not  precipitated  by 
copper  sulphate,  silver  nitrate,  or  sugar  of  lead.  Basic  lead  acetate 
gives,  on  the  contrary,  a  precipitate  which  is  soluble  in  boiling 
alcohol. 

Taurocholic  acid  is  best  prepared  from  decolorized,  crystallized 
dog-bile,  which  contains  only  tanrocholate.  The  solution  of  this 
bile  is  precipitated  by  basic  lead  acetate  and  ammonia,  and  the 
washed  precipitate  dissolved  in  boiling  alcohol.  The  filtrate  is  now 
treated  with  H^S,  and  this  filtrate  is  evaporated  at  a  gentle  heat  to 
a  small  volume,  and  treated  with  an  excess  of  water-free  ether. 
The  acid  sometimes  partially  crystallizes. 

Cheno-taurocholic  Acid.  This  is  tlie  most  essential  acid  of  goose-bile  and 
has  the  formula  C29H49NSO6.  This  acid,  though  little  studied,  is  amorphous 
and  soluble  in  water  and  alcohol. 

As  repeatedly  mentioned  above,  the  two  bile-acids  split  on 
boiling  with  acids  or  alkalies  into  non-nitrogenous  cholalic  acid  and 
glycocoll  or  taurin.  Therefore  we  will  now  describe  the  products 
of  this  cleavage. 

Cholalic  Acid.  The  ordinary  cholalic  acid  obtained  as  a  decom- 
position product  of  human  and  ox  bile,  which  occurs  regularly  in 
the  contents  of  the  intestine  and  in  the  urine  in  icterus,  has,  accord- 
ing to  Streckee^  and  nearly  all  recent  investigators,  the  constitu- 
tion C„,II  „0,.  According  to  Mtlius,^  cholalic  acid  is  a  monobasic 
alcohol-acid  with  a  secondary  and  two  primary  alcohol  groups..     Its 

formula  may  therefore  be  written  C  H  .  \  (CH^OH),.     On  oxida- 

(COOH 

'  Hoppe-Seyler,  Med.  chem.  Untersuch.,  S.  160. 

^  The  important  investigations  of  Strecker  on  the  bile-acids  may  be  found  in 
Ann.  d.  Chem,  u.  Pharm.,  Bdd.  65,  67,  and  70. 

3  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  19,  pp.  369-379  and  2000-2009. 


CHOLALIC  ACID.  229 

tion  it  first  yields  dehydrocholalic  acid  (author)',  and  tlien  hilimnc 
acid  (Clete).'  The  formnlas  of  these  acids  (when  we  take  C',^  for 
the  cholalic  acid)  are  C^JIj^O^  and  C^JIj^Og.  On  reduction  (in 
putrefaction)  cholalic  acid  may  yield  desoxy cholalic  acid,  C^^H^^O^ 
(Mtlius)/ 

Cholalic  acid  crystallizes  j^artly  with  one  molecule  of  water,  in 
rhombic  plates  or  prisms,  and  partly  in  larger  rhombic  tetrahedra 
or  octahedra  with  1  mol.  of  alcohol  of  crystallization  (Mylius). 
These  crystals  become  quickly  opaque  and  porcelain-white  in  the 
air.  They  are  quite  insoluble  in  water  (in  4000  pai'ts  cold  and  750 
parts  boiling),  rather  soluble  in  alcohol,  but  soluble  with  difficulty 
in  ether.  The  amorphous  cholalic  acid  is  less  insoluble.  The  solu- 
tions have  a  bitter-sweetish  taste.  The  crystals  lose  their  alcohol 
of  crystallization  only  after  a  lengthy  heating  to  100-120°  C.  The 
acid  free  from  water  and  alcohol  melts  at  -|-  195°  C. 

The  alkali  salts  are  readily  soluble  in  water,  but  when  treated 
with  a  concentrated  caustic  or  carbonated  alkali  solution  may  be 
separated  as  an  oily  mass  which  becomes  crystalline  on  cooling. 
The  alkali  salts  are  not  readily  soluble  in  alcohol,  and  on  the  evap- 
oration of  the  alcohol  they  may  crystallize.  The  specific  rotatory 
power  of  the  sodium  salt  is  (a')D  =  -\-  31°. -4.  The  watery  solution 
of  the  alkali  salts,  when  not  too  dilute,  is  precipitated  immediately 
or  after  some  time  by  sugar  of  lead  or  by  barium  chloride.  The 
barium  salt  crystallizes  in  fine,  silky  needles,  and  it  is  rather  insolu- 
ble in  cold,  but  somewhat  easily  soluble  in  warm  water.  The 
barium  salt,  as  well  as  the  lead  salt  which  is  insoluble  in  water,  is 
soluble  in  warm  alcohol. 

Cholalic  acid  is  best  prepared  from  ox-bile  by  the  following 
method  as  suggested  by  Mylius:  '  Boil  the  bile  for  21  hours  with 
5  parts  its  weight  of  a  30,^^  caustic-soda  solution,  replacing  the  water 
lost  by  evaporation.  Now  saturate  the  liquid  with  CO^  and  evap- 
orate nearly  to  dryness.  The  residue  is  extracted  with  96«^  alcohol, 
and  this  alcoholic. extract  diluted  with  water  until  it  contains  at  the 
most  20^?;  alcohol,  and  completely  precipitated  with  a  BaCl,  solu- 
tion. The  precipitate,  which  contains  besides  fatty  acids  also  the 
choleic  acid,  is  filtered  and  the  cholalic  acid  precipitated  from  the 
filtrate  by  hydrochloric  acid.  After  the  cholalic  acid  has  gradually 
crystallized  out  it  is  repeatedly  recrystallized  from  alcohol  or 
methyl  alcohol. 

'  Ber.  d.  deutscli.  cliem.  Gesellsch.,  Bd.  14,  S.  71. 
«  Bull.  Soc.  Cliim.,  Tome  35.  *  L.  c. 

4  Zeitschr.  f.  physiol.  Chem..  Bd.  12. 


230  TEE  LIVER. 

Choleic  Acid  is  another  cholalic  acid  -with  the  formula  Cj^H^^O^ 
(Lassae-Cohn ')  named  by  Latschin-off.^  This  acid,  which  oc- 
curs in  varying  but  always  small  quantities  in  ox-bile,  is  probably 
identical  with  desoxycholalic  acid.  Choleic  acid  first  yields  deJiy- 
drocholeic  acid,  C^^Hj^O^,  and  then  cliolanic  acid,  C^^Hj^Og,  on 
oxidation. 

Choleic  acid  may  be  obtained  from  the  above-mentioned  barium 
precij^itate  by  first  converting  the  barium  salts  into  sodium  salts  by 
sodium  carbonate  and  then  fractionally  precipitating  the  fatty  acids 
by  barium  acetate  and  separating  the  choleic  acid  from  the  filtrate 
by  hydrochloric  acid  and  recrystallizing  several  times  from  glacial 
acetic  acid. 

Fellic  Acid,  C23H^„0^,  is  a  cholalic  acid,  so  called  by  Schotte]S!',' 
and  which  he  obtained  from  human  bile,  along  with  the  ordinary 
acid.  This  acid  is  crystalline,  is  insoluble  in  water,  and  yields 
barium  and  magnesium  salts  which  are  very  insoluble.  It  does  not 
give  Pettenkofer's  reaction  easily  and  gives  a  more  reddish-blue 
color. 

The  conjugate  acids  of  human  bile  have  not  been  investigated. 
To  all  appearance  human  bile  contains  under  different  circum- 
stances various  conjugate  bile-acids.  In  some  cases  the  bile-salts  of 
human  bile  are  precipitated  by  BaCl^,  and  in  others  not.  Accord- 
ing to  the  latest  statements  of  Lassar-Cohist  *  three  cholalic  acids 
may  be  prepared  from  human  bile,   namely,  ordinary  cholalic 

ACID,  CHOLEIC  ACID,  and  FELLIC  ACID. 

The  hyo-glycocholic  and  cheno-taurocholic  acids  as  well  as  the 
glycocholic  acid  of  the  bile  of  rodents  yield  corresponding  cholalic 
acids. 

On  boiling  with  acids,  on  putrefaction  in  the  intestine,  or 
on  heating,  cholalic  acids  lose  water  and  are  converted  into  an 
anhydride,  the  so-called  dyslysiii.  The  dyslysin,  C^^H^^Og,  corre- 
sponding to  ordinary  cholalic  acid,  and  which  occurs  in  f^ces,  is 
amorphous,  insoluble  in  water  and  alkalies.  Choloidic  acid, 
Cj^HjgO^,  is  called  the  first  anhydride  or  an  intermediate  product 
in  the  formation  of  dyslysin.  On  boiling  dyslysin  with  caustic 
alkali  it  is  reconverted  into  the  corresponding  cholalic  acid< 

'  Zeitsclir.  f.  pliysiol.  Cbem.,  Bd.  17,  S.  606. 

^  Ber.  d.  deutsch.  chem.  Gesellscli.,  Bdd.  18  and  20. 

^  Ibid.,  Bd.  11,  S.  268. 

*  Ber.  d.  deutscli.  cliem.  Gesellsch.,  Bd.  27,  S.  1339. 


QLYCOCOLL   AND   TAURIN.  231 

GlycocoU,  CJI^NO,,  or  amido-acetic  acid,  NH^.CH^.COOH, 
also  called  glycin,  or  sugar  of  gelatin,  has  been  found  in  the 
muscles  oi  peden  irradians,  but  it  is  of  special  interest  as  a  decom- 
position product  of  certain  protein  substances — gelatin  and  spongin 
— as  also  of  hippuric  acid  or  glycocholic  acid  on  splitting  them  by 
boiling  with  acids. 

GlycocoU  forms  colorless,  often  large,  hard  rhombic  crystals  or 
four-sided  prisms.  The  crystals  taste  sweet  and  dissolve  easily  in 
cold  (4.3  parts)  water.  They  are  insoluble  in  alcohol  and  ether;  in 
warm  spirits  of  wine  they  dissolve,  but  with  difficulty.  GlycocoU 
combines  with  acids  and  bases.  Under  the  last-mentioned  combina- 
tions we  must  mention  those  with  copper  and  silver.  GlycocoU 
dissolves  copper  hydroxide  in  alkaline  liquids,  but  does  not  reduce 
it  at  the  boiling  temperature.  A  boiling-hot  solution  of  glycocoll 
dissolves  freshly  precipitated  copper  hydroxide,  forming  a  blue 
liquid  from  which  dark-blue  needles  crystallize  on  cooling,  if  the 
liquid  is  sufficiently  concentrated.  The  combination  of  glycocoll 
with  HCl  is  soluble  in  water  and  alcohol. 

Glycocoll  is  best  prepared  from  hippuric  acid  by  boiling  it  10-12 
hours  with  4  parts  of  dilute  sulphuric  acid,  1  :  6.  After  cooling 
separate  the  benzoic  acid,  concentrate  the  filtrate,  remove  the 
remainder  of  the  benzoic  acid  by  shaking  with  ether,  remove  the 
sulphuric  acid  by  BaCOg,  and  evaporate  the  filtrate  to  crystalliza- 
tion. In  the  preparation  and  quantitative  estimation  of  glycocoll 
from  .gelatin  we  can  proceed  according  to  Gojstnekmann's  '  modi- 
fication of  Oh.  Fischer's  '  method.  The  gelatin  is  decomposed 
by  sulphuric  acid,  the  sulphuric  acid  removed  by  lead  carbonate, 
the  glycocoll  transformed  into  hippuric  acid  by  benzoyl  chloride 
and  caustic  soda.  This  solution  is  acidified  with  sulphuric  acid, 
extracteil  with  acetic  ether,  and  the  syrupy  residue  of  acetic  ether 
dissolved  in  chloroform  containing  benzol.  The  precipitated  hip- 
puric acid  after  24  hours  is  collected  on  a  filter  and  first  washed 
with  chloroform  containing  benzol  and  then  with  pure  chloroform. 

Taurin,  C^H^NSO^,  or  amido-ethylsulphonic  acid,  NH  C^H^. 
SO.^OH.  This  body  is  well  known  as  a  splitting  product  of  tauro- 
cholic  acid,  and  may  occur  in  small  quantities  in  the  contents  of 
the  intestine.  It  has  also  been  found  in  the  lungs  and  kidneys  of 
oxen  and  in  the  blood  and  muscles  of  cold-blooded  animals. 

Taurin  crystallizes  in  colorless,  often  in  large,  shining,  4-6-sided 
prisms.     It  dissolves  in  15-16  parts  of  water  at  ordinary  tempera- 

'  Pfliiger's  Arch.,  Bd.  59. 

'  Zeitsclir.  f.  plijsiol.  Chem.,  Bd   19. 


232  THE  LIVEB. 

tnres,  but  rather  more  easily  in  warm  water.  It  is  insoluble  in 
absolute  alcohol  and  ether;  in  cold  spirits  of  wine  it  dissolves 
slightly,  but  more  when  warm.  Taurin  yields  acetic  and  sulphurous 
acids,  but  no  alkali  sulphides,  on  boiling  with  strong  caustic  alkali. 
The  amount  of  sulphur  can  be  determined  as  sulphuric  acid  after 
fusing  with  saltpetre  and  soda.  Taurin  combines  with  metallic 
oxides.  The  combination  with  mercuric  oxide  is  white,  insoluble, 
and  is  formed  when  a  solution  of  taurin  is  boiled  with  freshly  pre- 
cipitated mercuric  oxide  (J.  Laistg').  This  combination  may  be 
used  in  detecting  the  presence  of  taurin.  Taurin  is  not  precipitated 
by  metallic  salts. 

The  preparation  of  taurin  from  bile  is  very  simple.  The  bile  is 
boiled  a  few  hours  with  hydrochloric  acid.  The  filtrate  from  the 
dyslysin  and  choloidic  acid  is  concentrated  well  in  the  water-bath, 
and  filtered  so  as  to  remove  the  common  salt  and  other  substances 
which  have  separated.  Then  evaporate  to  dryness,  and  treat  the 
residue  with  strong  alcohol,  which  dissolves  the  hydrochlorate  of 
glycocoll,  while  the  taurin  remains.  (The  alcoholic  solution  of 
hydrochlorate  of  glycocoll  may  be  used  in  the  preparation  of 
glycocoll  by  evaporating  the  alcohol  and  dissolving  the  residue  in 
water,  decomposing  the  solution  with  lead  hydroxide,  filtering,  and 
freeing  the  solution  from  lead  by  H^S,  and  strongly  concentrating 
this  filtrate.  The  crystals  which  separate  are  dissolved  and  decolor- 
ized by  animal  charcoal,  and  the  solution  evaporated  to  crystalliza- 
tion. )  The  above-obtained  residue  containing  the  taurin  is  dissolved 
in  as  little  water  as  possible,  filtered  warm,  and  treated  with  an 
excess  of  alcohol.  The  crystalline  precipitate  which  immediately 
forms  is  filtered  as  soon  as  possible,  and  the  taurin  now  separates, 
on  cooling,  in  very  long  needles  or  prisms.  These  crystals  may 
be  purified  by  recrystallization  from  a  little  warm  water. 

Though  the  taurin  shows  no  positive  reactions,  it  is  chiefly 
identified  by  its  crystalline  form,  by  its  solubility  in  water  and 
insolubility  in  alcohol,  by  its  combination  with  mercuric  oxide,  by 
its  non-precipitability  by  metallic  salts,  and  above  all  by  its  con- 
taining sulphur. 

The  Detection  of  Bile-acids  in  Animal  Fluids.  To 
obtain  the  bile-acids  pure  so  that  Pettenkofer's  test  can  be 
applied  to  them,  the  proteid  and  fat  must  first  be  removed.  The 
proteid  is  removed  by  making  the  liquid  first  neutral  and  then  add- 
ing a  great  excess  of  alcohol,  so  that  the  mixture  contains  at  least 
85  vols,  per  cent  of  water-free  alcohol.  Now  filter,  extract  the  pre- 
cipitated proteid  with  fresh  alcohol,  unite  all  filtrates,  distil  the 
alcohol,  and  evaporate  to  dryness.  The  residue  is  completely 
exhausted  with  strong  alcohol,  filtered,  and  the   alcohol  entirely 

»  See  Maly's  Jaliresber.,  Bd.  6,  S.  73. 


BILIRUBIN.  233 

evaporated  from  the  filtrate.  The  new  residue  is  dissolved  in 
water,  and  filtered  if  necessary,  and  the  solution  precipitated  by 
basic  lead  acetate  and  ammonia.  The  washed  jirecipitate  is  dis- 
solved in  boiling  alcohol,  filtered  while  warm,  and  a  few  drops  of 
soda  solution  added.  Then  evaporate  to  dryness,  extract  the 
residue  with  absolute  alcohol,  filter,  and  add  an  excess  of  ether. 
The  precipitate  now  formed  may  be  used  for  Pettexkofek's  test. 
It  is  not  necessary  to  wait  for  a  crystallization;  but  one  must  not 
consider  the  crystals  which  form  in  the  liquid  as  being  positively 
crystallized  bile.  It  is  also  possible  for  needles  of  alkali  acetate  to 
be  formed.  For  the  detection  of  bile-acids  in  urine  see  Chapter 
XV. 

Bile-pigments.  The  bile-coloring  matters  known  thus  far  are 
relatively  numerous,  and  in  all  jirobability  there  are  still  more. 
Most  of  the  known  bile-pigments  are  not  found  in  the  normal  bile, 
but  occur  either  in  post-mortem  bile  or,  principally,  in  the  bile 
concrements.  The  pigments  which  occur  under  physiological  con- 
ditions are  the  reddish-yellow  hilirubin,  the  green  biliverdin,  and 
sometimes  there  is  also  observed  in  fresh  human  bile  a  pigment 
closely  allied  to  liydrohiliruhin.  The  pigments  found  in  gall-stones 
are  (besides  the  hiliruhin  and  hiliverdin)  bilifuscin,  bihpircsin, 
hilihumin,  hilicyanin  (and  clioletelin  ?).  Besides  these,  others  have 
been  observed  in  human  and  animal  bile.  The  two  above-men- 
tioned physiological  pigments,  bilirubin  and  biliverdin,  are  those 
which  serve  to  give  the  golden-yellow  or  orange-yellow  or  sometimes 
greenish  color  to  the  bile,  or  when,  as  is  most  frequently  the  case 
in  ox-bile,  the  two  pigments  are  present  in  the  bile  at  the  same 
time,  producing  the  different  shades  between  reddish  brown  and 
green. 

Bilirubin.  This  pigment,  according  to  the  common  accepta- 
tion, has  the  formula  C^ .H.^N^Oj  (Maly  ')  and  is  designated  by 
the  names  cholepyrrhin,  BiLiPHiEiN,  bilifulvin",  and  h.ejia- 
TOiDiisr.  It  occurs  chiefly  in  the  gall-stones  as  bilirubin-calcium. 
It  occurs  in  the  liver-bile  of  all  vertebrates  and  in  the  bladder-bile 
especially  in  man  and  carnivora;  sometimes,  however,  the  latter 
Avhen  fasting  or  in  a  starving  condition  may  have  a  green  bile.  It 
occurs  also  in  the  contents  of  the  small  intestine,  in  blood-serum  of 
the  horse,  in  old  blood  extravasations  (as  haematoidin),  and  in  the 
urine  and  the  yellow-colored  tissue  in  icterus.  Bilirubin  is  derived 
in  all  probability  from  heematin,  which  it  closely  resembles.     It 

'  Wien.  Sitzungsber.,  Bdd.  57  and  70. 


234  THE  LIVER. 

is  converted  into  hydroMlirulin,  Cj^H^^lST^O,  (Malt  ')  by  hydrogen 
in  a  nascent  state.  It  is  claimed  by  several  investigators  to  be 
identical  with  the  urinary  pigment  urobilin,  as  well  as  with  sterco- 
hilin  (Masius  and  VAi^rLAiR'),  which  is  found  in  the  contents  of 
the  intestine.  There  is  no  doubt  that  a  great  similarity  exists 
between  these  pigments,  but  their  identity  is  emphatically  denied 
by  MacMunk.'  On  oxidation  bilirubin  yields  biliverdin  and  other 
coloring  matters  (see  below). 

Bilirubin  is  partly  amorphous  and  partly  crystalline.  The 
amorphous  bilirubin  is  a  reddish-yellow  powder  of  nearly  the  same 
color  as  amorphous  antimony  sulphide;  the  crystalline  bilirubin  has 
nearly  the  same  color  as  crystallized  chromic  acid.  The  crystals, 
which  can  easily  be  obtained  by  allowing  a  solution  of  bilirubin  in 
chloroform  to  spontaneously  evaporate,  are  reddish-yellow,  rhombic 
plates,  whose  obtuse  angles  are  often  rounded. 

Bilirubin  is  insoluble  in  water,  slightly  soluble  in  ether,  some- 
what more  soluble  in  alcohol,  easily  soluble  in  chloroform,  especially 
in  the  warmth,  and  less  soluble  in  benzol,  carbon  disulphide,  amyl 
alcohol,  fatty  oils,  and  glycerin.  Its  solutions  show  no  absorption- 
bands,  but  only  a  continuous  absorption  from  the  red  to  the  violet 
end  of  the  spectrum,  and  they  have,  even  on  diluting  greatly, 
(1  :  500000)  in  a  layer  1.5  c.cm.  thick  a  decided  yellow  color.  If 
a  dilute  solution  of  bilirubin  in  water  is  treated  with  an  excess  of 
ammonia  and  then  with  a  zinc-chloride  solution,  the  liquid  is  first 
colored  deep  orange  and  then  gradually  olive-brown  and  then  green. 
This  solution  first  gives  a  darkening  of  the  violet  and  blue  part  of 
the  spectrum  and  then  the  bands  of  alkaline  cholecyanin  (see  below), 
or  at  least  the  bands  of  the  pigment  in  the  red  between  C  and  D 
close  to  C.  This  is  a  good  reaction  for  bilirubin.  The  combina- 
tions of  bilirubin  with  alkalies  are  insoluble  in  chloroform,  and 
bilirubin  may  be  separated  from  its  solution  in  chloroform  by  shak- 
ing with  dilute  caustic  alkali  (differing  from  lutein).  Solutions  of 
bilirubin-alkali  in  water  are  precipitated  by  the  soluble  salts  of  the 
alkaline  earths  and  also  by  metallic  salts. 

If  an  alkaline  solution  of  bilirubin  be  allowed  to  stand  in  con- 
tact with  the  air,  it  gradually  absorbs  oxygen  and  green  biliverdin 
is  formed.     Biliverdin  is  also  formed  from  bilirubin  by  oxidation 

>  Ann.  d.  Cliein.,  Bd.  163. 

2  Centralbl   f.  d.  med.  Wissensch,,  1871,  S.  369. 

»  Journal  of  Physiol.,  Vol.  10,  p.  71. 


RE  ACTIONS  FOR  BILE  PIGMENTS.  235 

nnder  other  conditions.  A  green  coloring  matter  similar  in  appear- 
ance is  formed  by  the  action  of  other  reagents  such  as  CI,  Br, 
and  I.  In  these  cases  it  does  not  seem  to  be  biliverdin,  but  a  sub- 
stitution product  of  bilirubin  (Thudichum,'  Maly°),  which  is 
obtained. 

Gmelin's  Reaction  for  Bile-pigments.  If  we  carefully  ponr 
under  a  solution  of  bilirnbin-alkali  in  water  nitric  acid  containing 
some  nitrous  acid,  we  obtain  a  series  of  colored  layers  at  the  junc- 
ture of  the  two  liquids,  in  the  following  order  from  above  down- 
wards: green,  blue,  violet,  red,  and  reddish  yellow.  This  color 
reaction,  Gmelin's  test,  is  very  delicate  and  serves  to  detect  the 
presence  of  one  part  bilirubin  in  80,000  parts  liquid.  The  green 
ring  must  never  be  absent;  and  also  the  reddish  violet  must  be 
present  at  the  same  time,  otherwise  the  reaction  may  be  confused 
with  that  for  lutein,  which  gives  a  blue  or  greenish  ring.  The 
nitric  acid  must  not  contain  too  much  nitrous  acid,  for  then  the 
reaction  takes  place  too  quickly  and  it  does  not  become  typical. 
Alcohol  must  not  be  present  in  the  liquid,  because,  as  is  well 
known,  it  gives  a  play  of  colors,  in  green  or  blue,  with  the  acid, 

Huppert's  Beaction.  If  a  solution  of  bilirubin-alkali  is  treated 
with  milk  of  lime  or  with  calcium  chloride  and  ammonia,  a  precipi- 
tate is  produced  consisting  of  bilirubin-calcium.  If  this  moist  pre- 
cipitate, which  has  been  washed  with  water,  is  placed  in  a  test-tube 
and  the  tube  half  filled  with  alcohol  which  has  been  acidified  with 
sulphuric  acid,  and  heated  to  boiling  for  some  time,  the  liquid 
becomes  emerald-green  or  bluish  green  in  color.  This  reaction  is  a 
good  and  easily  performed  test  for  bile-pigments. 

In  regard  to  the  modifications  of  Gmelin's  test  and  certain 
other  reactions  for  bile-pigments,  see  Chapter  XV  (Urine). 

That  the  characteristic  play  of  colors  in  Gmelin's  test  is  the 
result  of  an  oxidation  is  generally  admitted.  The  first  oxidation 
step  is  the  green  biliverdin.  Then  follows  a  blue  coloring  matter 
which  Heinsius  and  Campbell'  call  bilicyatiin and  Stokvis'  calls 
cholecycumi,  and  which  shows  a  characteristic  absorption-spectrum. 
The  neutral  solutions  of  this  coloring  matter  are,  according  to 
Stokvis,  bluish  green  or  steel-blue  with  a  beautiful  blue  fluores- 

'  Journal  of  the  Chem    Soc,  (2)  Vol.  13. 

'  Wien.  Sitzungsber.,  Bd.  72. 

«  Pflliger's  Arch..  Bd.  4,  S.  539. 

*  Centralbl.  f.  d.  med.  Wissensch.,  1872,  S.  785. 


236  TEE  LIVER. 

cence.  The  alkaline  solutions  are  green  and  have  no  marked 
fluorescence.  The  neutral  and  alkaline  solutions  show  three  absorp- 
tion-bands, one  sharp  and  dark  in  the  red  between  C  and  D,  nearer 
to  (7;  a  second,  less  defined,  covering  i);  and  a  third,  forming  only 
a  faint  shadow,  in  the  green,  exactly  in  the  middle,  between  D 
and  E.  The  strongly  acid  solutions  are  violet-blue  and  show  two 
bands,  described  by  Jaffe,  between  the  lines  C  and  E,  separated 
from  each  other  by  a  narrow  space  near  D.  The  next  oxidation 
step  after  these  blue  coloring  matters  is  a  red  pigment,  and  lastly  a 
yellowish-brown  pigment,  called  choletelin  by  Malt,^  which  in 
neutral  alcoholic  solutions  does  not  give  any  absorption  spectrum, 
but  in  acid  solution  gives  a  band  between  l  and  F. 

Bilirubin  is  best  prepared  from  gall-stones  of  oxen,  these  con- 
cretions being  very  rich  in  bi]irubirL,-calcium.  The  finely  powdered 
concrement  is  first  exhausted  with  ether  and  then  with  boiling 
water,  so  as  to  remove  the  cholesterin  and  bile-acids.  The  powder 
is  then  treated  with  hydrochloric  acid,  which  sets  free  the  pigment. 
Wash  thoroughly  with  water  and  alcohol,  dry,  and  extract  re- 
peatedly with  boiling  chloroform.  After  distilling  the  chloroform 
from  the  solution,  treat  the  j)owdered  residue  with  absolute  alcohol 
to  remove  the  bilifuscin;  dissolve  the  remaining  bilirubin  in  a  little 
chloroform;  precipitate  it  from  this  solution  by  alcohol,  and  do  this 
several  times  if  necessary.  The  bilirubin  is  finally  dissolved  in 
boiling  chloroform  and  allowed  to  crystallize  on  cooling.  The 
quantitative  estimation  of  bilirubin  may  be  made  by  the  spectro- 
photometrical  method,  according  to  the  steps  suggested  for  the 
blood-coloring  matters. 

Biliverdin,  Cj^Hj^lNrjO^.  This  body,  which  is  formed  by  the 
oxidation  of  bilirubin,  occurs  in  the  bile  of  many  animals,  in 
vomited  matter,  in  the  placenta  of  the  bitch  (?),  in  the  shells  of 
birds'  eggs,  in  the  urine  in  icterus,  and  sometimes  in  gall-stones, 
although  in  very  small  quantities. 

Biliverdin  is  amorphous,  or  at  least  it  has  not  been  obtained  in 
well-defined  crystals.  It  is  insoluble  in  water,  ether,  and  chloro- 
form (this  is  trne  at  least  for  the  artificially  prepared  biliverdin, 
while  the  green  pigment  of  ox-bile  is  soluble  in  chloroform,  accord- 
ing to  MacMunn^),  but  is  soluble  in  alcohol  or  glacial  acetic  acid, 
showing  a  beautiful  green  color.     It  is  dissolved  by  alkalies,  giving 

1  Wien.   Sitzungsber.,  Bd.  59.     See  also  JafFe,  Centralbl.   f.  d.  med.   Wis- 
senscli.,  1868,  and  Heinsius  and  Campbell,  Pfluger's  Arch.,  Bd.  4. 
"^  Journal  of  Physiol,,  Vol.  6. 


BILIVERDIN.  237 

a  brownish -green  color,  and  this  sohition  is  precipitated  by  aoids, 
as  well  as  by  calcium,  barium,  and  lead  salts.  Biliverdin  gives 
Huppert's  and  Gmelin's  reactions,  commencing  with  the  blue 
color.  It  is  converted  into  hydrobilirubin  by  nascent  hydrogen. 
On  allowing  the  green  bile  to  stand,  also  by  the  action  of  ammonium 
sulphide,  the  biliverdin  may  be  reduced  to  bilirubin  (Haycraft 
and  ScoFiELD '). 

Biliverdin  is  most  simply  prepared  by  allowing  a  thin  layer  of 
an  alkaline  sohition  of  bilirubin  to  stand  exposed  to  the  air  in  a  dish 
until  the  color  is  brownish  green.  The  solution  is  then  precipitated 
by  hydrochloric  acid,  the  precipitate  washed  with  water  until  no 
HCl  reaction  is  obtained,  then  dissolved  in  alcohol  and  the  pigment 
again  separated  by  the  addition  of  water.  Any  bilirubin  present 
may  be  removed  by  means  of  chloroform. 

Bilifuscin,  so  named  by  Stadeler^,  is  an  amorphous  brown  pigment, 
solul)le  in  alcohol  and  alkalies,  nearly  insoluble  in  water  and  ether,  and  soluble 
with  great  difficulty  in  chloi'oform  (when  bilirubin  is  not  present  at  the  same 
time).  When  pure  bilifuscin  does  not  give  (tMELIN's  reaction.  It  is  found  in 
post-mortem  bile  and  gall-stones.  Biliprasin  is  a  green  pigment  prepared  by 
Stadeler  from  gall-stones,  which  perhaps  is  only  a  mixture  of  biliverdin-and 
bilirubin.  Bilihuviin  is  the  name  given  by  Stadeler  to  that  brownish 
amorphous  residue  which  is  left  after  extracting  gall-stones  with  chloroform, 
alcohol,  and  ether.  It  does  not  give  Gmei.in's  test.  Bilicyanin  is  also  found 
in  human  gall-stones  (Heinsius  and  Campbell).  Ghololmmatiii,  so  called  by 
MacMunn,*  is  a  pigment  often  occurring  in  sheep-  and  ox-bile  and  character- 
ized by  four  absorption-bands,  and  which  is  formed  from  hsematin  by  the 
action  of  sodium  amalgam.  In  the  dried  condition  obtained  by  the  evapo- 
ration of  the  chloroform  solution  it  is  green,  and  in  alcoholic  solution  olive- 
brown. 

Gmelin's  and  Huppert's  reactions  are  generally  used  to  detect 
the  presence  of  bile-pigments  in  animal  fluids  or  tissues.  The  first, 
as  a  rule,  can  be  performed  directly,  and  the  presence  of  proteid 
does  not  interfere  with  it,  but,  on  the  contrary,  it  brings  out  the 
play  of  colors  more  strikingly.  If  blood-coloring  matters  are 
present  at  the  same  time,  the  bile-coloring  matters  are  first  precipi- 
tated by  the  addition  of  sodium  phosphate  and  milk  of  lime.  This 
precipitate  containing  the  bile-pigments  may  be  used  directly  in 
Huppert's  reaction,  or  may  be  treated  with  water  and  some  hydro- 
chloric acid,  and  then  shaken  with  chloroform  free  from  alcohol, 
and  this  chloroform  solution  used  in  testing  for  the  bile-pigments. 


1  Centralbl.  f.  Physiol.,  1889,  S.  322,  and  Zeitschr.  f,  physiol.  Chem  , 
Bd.  14. 

'  Vierteljahrschr.  d.  naturf.  Gesellsch.  in  Zurich,  Bd.  8,  cited  from  Hoppe- 
Seyler,  Physiol,  u.  path.  chem.  Analyse,  6.  Aufl.,  S.  225. 

'  Journal  of  Physiol. ,  Vol.  6. 


238  THE  LIVER. 

Bilirabin  is  detected  in  blood,  according  to  Hedexius,*  by  precipi- 
tating the  proteins  by  alcohol,  filtering  and  acidifying  the  filtrate 
\rith  hydrochloric  or  salphnric  acid,  and  boiling.  The  liquid 
becomes  of  a  greenish  color.  Seram  and  seroas  fluids  may  be  boiled 
directly  ^vith  a  little  acid  after  the  addition  of  alcohol. 

Besides  the  bile-acids  and  bile-pigments  Vs%  also  have  in  the  bile 
cJiolesteriyi,  lecitJiin, palmithi,  stearin,  oJein,  and  soajis  of  the  corre- 
sponding/a^/^ acids.  Lassae-Cohx'  has  also  found  myristic  acid 
in  ox-bile.  In  some  animals  the  bile  contains  a  diastoiic  enzyme. 
CJioUii  and  glycero-phosphoric  acid,,  when  they  are  present,  may  be 
considered  as  decomposition  products  of  lecithin.  Urea  occurs, 
though  only  as  traces,  as  a  physiological  constituent  of  human,  ox, 
and  dog  bile.  T7rea  occurs  in  the  bile  of  the  shark  and  ray  in  such 
large  quantities  that  it  forms  one  of  the  chief  constituents  of  the 
bile.^  The  mijieral  constituents  of  the  bile  are,  besides  the  alkalies, 
to  which  the  bile  acids  are  united,  sodium  and  potassium  chloride, 
calcium  and  magnesium  phosphate,  and  iron — 0.04-0.115  p.  m.  in 
human  bUe,  chiefly  combined  with  phosphoric  acid  (YouxG*). 
Traces  of  copper  are  habitually  present,  and  traces  of  zinc  are  often 
found.  Sulphates  are  entirely  absent  or  only  occur  in  very  small 
amounts. 

The  quantity  of  iron  in  the  bile  varies  very  much.  According 
to  XoYi  •  it  is  dependent  upon  the  kind  of  food,  and  in  dogs  it  is 
lowest  with  a  bread  diet  and  highest  with  a  meat  diet.  According 
to  Dastee  '  this  is  not  the  case.  The  quantity  of  iron  in  the  bile 
varies  even  though  a  constant  diet  is  kept  up,  and  the  variation  is 
dependent  upon  the  formation  and  destruction  of  blood.  The 
question  as  to  the  extent  of  elimination  by  the  bile  of  the  iron 
introduced  into  the  body  has  received  various  answers.  There  is 
no  doubt  that  the  liver  has  the  property  of  collecting  and  retaining 
iron  and  also  other  metals  from  the  blood.  Certain  investigators, 
such  as  XoTi  and  Kuxkel,"  are  of  the  opinion  that  the  introduced 
and  transitorily  retained  iron  in  the  liver  is  eliminated  by  the  bile, 

1  Upsala  Lakaref.  Forli.,  Bd.  29. 

'  Zeitsclir.  f.  pliysiol.  Chem.,  Bd.  17. 

"  Investigation  not  publislied  by  the  author. 

*  Journal  of  Anat.  and  PhvsioL,  Vol.  5,  p,  158. 

5  See  Malv's  Jahresber.,  Bd.  20,  S.  373. 

«  Arch,  de  Pbvsiol.,  (5)  Tome  3. 

'  Pflucrer's  Arch  .  Bd.  14. 


COMPOSITION  OF  THE  BILE.  239 

while  others,  such  as  Hamburgee,'  Gottlieb/  aud  Axselm,"  deny 
any  such  elimination  of  iron  by  the  bile. 

Quantitative  Com2)Ositio7i  of  the  Bile.  Complete  analyses  of 
human  bile  have  been  made  by  Hoppe-Seyler  and  his  pupils. 
The  bile  was  removed  as  fresh  as  possible  from  the  gall-bladder  of 
cadavers  whose  livers  showed  no  remarkable  change.  The  following 
figures  of  SocOLOFF^  are  the  average  of  six  analyses,  and  those  of 
Hoppe-Seyler  *  of  five  analyses.  The  relationship  between  the 
glycocholate  and  taurocholate  was  found  by  fusing  the  j^recipitate, 
consisting  of  biliary  alkalies  obtained  by  ether  from  the  alcoholic 
extract,  with  saltpetre  and  soda.  On  determining  the  amount  of 
sulphur  in  the  fused  mass  the  taurocholic  acid  can  be  calculated 
from  this.  100  parts  BaSO^  correspond  to  220.86  parts  taurocholic 
acid.     The  figures  are  parts  per  1000. 

Trifaxowski.'       Socoloff.      Hoppe-Seyler. 

I.  n. 

Mucin 24.8  13.0  |  „p,  ^^  12.9 

Remaining  bodies  insol.  in  alcohol.     4.5  14  6  f  oiM  j  _! 

Taiirocliolate 7.5  19.3  15.67  8.7 

Glycocholate 21.0  4.4  49.04  30.3 

Soaps 8.1  16.3  14.60  13.9 

Cholesteriu.    2.5  3.3  3.5 

Lecithin ..,)      -^  02  5.3 

Fat f      "^--^  3.6  7.3 

Ferric  phosphate . .  ....  0. 166 

Older  and  less  complete  analyses  of  human  bile  have  been  made 
by  Frerichs  and  v.  Gorup-Besaxez.  The  bile  analyzed  by  them 
was  from  perfectly  healthy  persoas  who  had  been  executed  or 
accidentally  killed.  The  two  analyses  of  Frerichs  are,  respec- 
tively, of  (I)  an  18-year-old  and  (II)  a  22-year-old  male.  The 
analyses  of  v.  Gorup-Besanez  are  of  (I)  a  man  of  -49  and  (II)  a 
woman  of  29.     The  results  are,  as  usual,  in  parts  per  1000. 

Frerichs.'  v.  Gorup-Besaxez.' 

I.  II.  I.             n. 

Water 860.0  859.2  822.7  898.1 

Solids 140.0  1408  177.3  101.9 

Biliary  salts 72.2  91.4  107.9        56.5 

Mucus  and  pigments 26.6  29  8  22.1         14.5 

Cholesterin 1.6  2.6)  ,^.3        o-,  „ 

Fat 3.2  9.2)  "^'"^        ^^-^ 

Inorganic  substances 6.5  7.7  10.8           6.2 


'  Zeitschr.  f.  physiol.  Chem.,  Bdd.  2  and  4. 

^Ihid.,  Bd.  15. 

'  Ueber  die  Eisenausscheidung  der  Galle.    Inaug.  Diss.    Dorpat,  1891. 

<iPflUger's  Arch.,  Bd.  12. 

•Physiol.  Chem.,  S.  301. 

•  Pfluger's  Arch.,  Bd.  9. 

'  Cit.  from  Hoppe-Seyler's  Physiol.  Chem.,  S.  299. 

8  Ibid. 


240  THE  LIVER. 

Hnman  liver-bile  is  poorer  in  solids  thaa  the  bladder-bile.  In. 
several  cases  it  only  contained  12-18  p,  m.  solids,  but  the  bile  in 
these  cases  is  hardly  to  be  considered  as  normal.  jACOBSE]sr ' 
found  22.4-22.8  p.  m.  solids  in  a  specimen  of  bile.  The  author,^ 
who  had  occasion  to  analyze  the  liver-bile  in  seven  cases  of  biliary 
fistula,  has  repeatedly  found  25-28  p.  m.  solids.  In  a  case  of  a 
corpulent  woman  the  quantity  of  solids  in  the  liver-bile  varied 
between  30.10-38.6  p.  m.  in  ten  days. 

Human  bile  sometimes,  bat  not  always,  contains  sulphur  in  an 
ethereal  sulphuric-acid  combination.  The  quantity  of  such  sulphur 
may  even  amount  to  ^—J  of  the  total  sulphur.  Human  bile  is 
habitually  richer  in  glycocholic  than  in  taurocholic  acid.  In  six 
cases  of  liver-bile  analyzed  by  the  author  the  relationship  of 
taurocholic  to  glycocholic  acid  varied  between  1  :  2.07  and 
1  :  14.36.  The  bile  analyzed  by  jACOBSEisr  contained  no  tauro- 
cholic acid. 

As  example  of  the  composition  of  human  liver-bile  we  give 
the  following  results  of  three  analyses  made  by  the  author.^  The 
results  are  calculated  in  parts  per  1000. 

Solids , 25.200  35.260  25.400 

Water 974  800  964.740  974.600 

Mucin  and  pigments 5.290  4.290  5.150 

Bile-salts 9.310  18.240  9.040 

Taurocbolate 3.034  2.079  3.180 

Glycocliolate 6.276  16.161  6.860 

Fatty  acids  from  soaps 1.230  1.360  1.010 

Cholesterin 0.630  1.600  1.500 

Lecithin >  ^  oon  0.574  0.650 

Fat S  0.956  0.610 

Soluble  salts 8.070  6.760  7.250 

Insoluble  salts 0.250  0.490  0.210 

Baginskt  and  Sommerfeld^  have  found  true  mucin,  mixed 
with  some  nucleoalbumin,  in  the  bladder-bile  of  children.  The  bile 
contained  on  an  average  896.5  p.  m.  water;  103.5  p.  m.  solids;  20 
p.  m.  mucin;  9.1  p.  m.  mineral  substances;  25.2  p.  m.  bile-salts, 
of  which  16.3  p.  m.  were  glycocholate  and  8.9  p.  m.  taurocbolate; 
3.4  p.  m.  cholesterin;  6.7  p.  m.  fat,  and  2.8  p.  m.  leucin. 

Amongst  the  mineral  constituents  the  chlorine  and  sodium 
occur  to  the  greatest  extent.     The  relationship  between  potassium 

'  Ber.  d.  deutscb.  cbem.  Gesellscb.,  Bd.  6. 

"^  Nova  Acta  Reg   Soc.  Scient.  Upsala,  Bd.  16. 

»  L.  c. 

*  Verbandl.  d.  pbysiol.  Gesellscb.  zu  Berlin,  1894-95,  Nos.  13,  14,  15. 


COMPOSITION  OF  THE  BILE.  241 

and  sodium  varies  considerably  in  different  biles.  Sulphuric  acid 
and  phosphoric  acid  only  occur  in  very  small  quantities.  The 
quantity  of  iron  in  the  liver-bile  in  three  cases  investigated  by  the 
AUTHOR  was  0.018-0.044  p.  m.,  calculated  on  the  fresh  bile. 

The  quantity  of  pigment  in  human  bile  is,  according  to  Koel- 
Patox,'  0.4-1.3  p.  m.  for  a  case  of  biliary  fistula.  The  method 
used  in  determining  the  pigments  in  this  case  was  not  quite  trust- 
worthy. More  exact  results  obtained  by  spectro-photometric 
methods  are  on  record  for  dogs'  bile.  According  to  Stadelman^N"  * 
dogs'  bile  contains  on  an  average  0.6-0.7  p.  m.  bilirubin.  At  the 
most,  only  7  milligrams  pignient  are  secreted  per  kilo  of  body  in 
the  24  hoars. 

In  animals  the  relative  proportion  of  the  two  acids  varies  very 
much.  It  has  been  found,  on  determining  the  amount  of  sulphur, 
that,  so  far  as  the  experiments  have  gone,  taurocholic  acid  is  the 
prevailing  acid  in  carnivorous  mammalia,  birds,  snakes,  and  fishes. 
Among  the  herbivora  sheep  and  goats  have  a  predominance  of 
taurocholic  acid  in  the  bile.  Ox-bile  sometimes  contains  tauro- 
cholic acid  in  excess,  in  other  cases  glycocholic  acid  predominates, 
and  in  a  few  cases  the  latter  occurs  almost  alone.  The  bile  of  the 
rabbit,  hare,  and  kangaroo  contains,  like  the  bile  of  the  pig,  almost 
exclusively  glycocholic  acid.  A  distinct  influence  on  the  relative 
amounts  of  the  two  bile-acids  by  different  foods  has  not  been 
detected.  Eitter  '  claims  to  have  found  a  decrease  in  the  quantity 
of  taurocholic  acid  in  calves  when  they  pass  from  the  milk  to  the 
plant  diet. 

In  the  above-mentioned  calculation  of  the  taurocholic  acid  from 
the  quantity  of  sulphur  in  the  bile-salts  it  must  be  remarked  that 
no  exact  conclusion  can  be  drawn  from  this  calculation  as  long  as 
we  have  not  investigated  whether  other  kinds  of  bile  contain  sul- 
phur in  combinations  other  than  taurocholic  acid,  as  in  human  and. 
shark  bile. 

The  gases  of  the  bile  consist  of  a  large  quantity  of  carbon  diox- 
ide, which  increases  with  the  amount  of  alkalies,  only  traces  of 
oxygen,  and  a  very  small  quantity  of  nitrogen. 

Little  is  known  in  regard  to  tlie  properties  of  the  bile  in  disease.  The  quan- 
tity of  urea  is  found  to  be  considerably  increased  in  uraemia.  Leucin  and 
tyrositi  are  observed  in  acute  yellow  atrophy  of  the  liver  and  in  typhus.    Traces 

'  Rep.  Lab.  Roy.  Soc.  Coll.  Phys.  Edinb.,  Vol.  3. 

^  Der  Icterus,  etc.     Stuttgart,  1891. 

'  Cit.  from  Maly's  Jahresber.,  Bd.  6,  S.  195. 


242  THE  LIVER. 

of  albumin  (without  regard  to  nucleoalbumin)  have  several  times  been  found  in 
the  human  bile.  The  so-called  pigmentary  acholia,  or  the  secretion  of  a  bile 
coutaiuing  bile-acids  but  no  bile-pigments,  has  also  been  repeatedly  noticed. 
In  all  such  cases  observed  by  Rittbe  '  he  found  a  fatty  degeneration  of  the 
liver-cells,  in  return  for  which,  even  in  excessive  fat  infiltration,  a  normal  bile 
containing  pigments  was  secreted.  The  secretion  of  a  bile  nearly  free  from 
bile-acids  has  been  observed  by  Hoppe-Setlee^  in  amyloid  degeneration  of  the 
liver.  In  animals,  dogs,  and  especially  rabbits  it  has  been  observed  that  the 
blood-pigments  pass  into  the  bile  in  poisoning  and  in  other  cases,  causing  a 
destruction  of  the  blood-corpuscles,  as  also  after  intravenous  hgemoglobin  injec- 
tion (Wertheimer  and  Meyer,^  Filehne,*  Stern"). 

Chemical  Formation  of  the  Bile.  The  first  question  to  be 
answered  is  the  following:  Do  the  specific  constituents  of  the  bile, 
the  bile-acids  and  bile-pigments,  originate  in  the  liver;  and  if  this 
is  the  case,  do  they  come  from  this  organ  only,  or  are  they  also 
formed  elsewhere  ? 

The  investigations  of  the  blood,  and  especially  the  comparative 
investigations  of  the  blood  of  the  portal  and  hepatic  veins  under 
normal  conditions,  have  not  given  any  answer  to  this  question.  To 
decide  this,  therefore,  it  is  necessary  to  extirpate  the  liver  of 
animals  or  isolate  it  from  the  circulation.  If  the  bile  constituents 
are  not  formed  in  the  liver,  or  at  least  not  alone  in  this  organ,  but 
only  eliminated  from  the  blood,  then,  after  the  extirpation  or 
removal  of  the  liver  from  the  circulation,  an  accumulation  of  the 
bile  constituents  is  to  be  expected  in  the  blood  and  tissues.  If  the 
bile  constituents,  on  the  contrary,  are  formed  exclusively  in  the 
liver,  then  the  above  operation  naturally  would  give  no  such  result. 
If  the  choledochus  duct  is  tied,  then  the  bile  constituents  will  be 
collected  in  the  blood  or  tissues  whether  they  are  formed  in  the 
liver  or  elsewhere. 

From  these  principles  Kobker  '  has  tried  to  demonstrate  by 
experiments  on  frogs  that  the  hile-acids  are  produced  exclusively  in 
the  liver.  While  he  was  unable  to  detect  any  bile-acids  in  the  blood 
and  tissues  of  these  animals  after  extirpation  of  the  liver,  still  he 
was  able  to  discover  them  on  tying  the  choledochus  duct.  The 
investigations  of  Ludwig  and  Fleischl  '  show  that  in  the  dog  the 

'Compt.  rend.,  Tome  74,  and  Journ.  de  I'anat.  et  de  la  physiol.,  1873, 
2  Physiol.  Chem.,  S.  317. 
*  Compt.  rend.,  Tome  108. 
4  Virchow's  Arch  ,  Bd.  131. 
5i6fd.,  Bd.  133. 

^  See  Heidenhain,  Physiologic  der  Absonderungsvorgange  in  Hermann's 
flandbuch,  Bd.   5. 

'•  Arbeiten  aus  der  physiol.  Anstalt  zu  Leipzig,  Jahrgang  9. 


FORMATION  OF  BILE  ACIDS.  243 

bile-acids  originate  in  the  liver  alone.  After  tying  the  choledochus 
dnct  they  observed  that  the  bile  constituents  were  absorbed  by  the 
lymj)hatic  vessels  and  passed  into  the  blood  through  the  thoracic 
dnct.  Bile-acids  could  be  detected  in  the  bfeod  after  such  an 
operation,  while  they  could  not  be  detected  in  the  normal  blood. 
But  when  the  choledochus  and  thoracic  ducts  were  both  tied  at  the 
same  time,  then  not  the  least  trace  of  bile-acids  could  be  detected 
in  the  blood,  while  if  they  are  also  formed  in  other  organs  and 
tissues  they  should  have  been  present. 

Other  ways  have  been  tried  to  demonstrate  the  formation  of 
bile-acid  in  the  liver-cells.  Alex.  Schmidt  and  Kallmetee  '  have 
shown  that  the  isolated  liver-cells,  which  have  been  washed  with  a 
physiological  XaCl  solution,  have  the  property,  in  the  presence  of 
haemoglobin  and  glycogen,  of  increasing  the  quantity  twofold,  of 
substances  soluble  in  alcohol  but  insoluble  in  ether.  This  tends  to 
show  the  formation  of  bile  alkalies. 

From  older  statements  of  Cloez  and  Yulpiax  as  Avell  as  Vir- 
CHOW  the  bile-acids  also  occur  in  the  suprarenal  capsule.  These 
statements  have  not  been  confirmed  by  later  investigations  of 
Stadelmaxx  and  Beier.''  At  the  present  time  we  have  no  ground 
for  supposing  that  the  bile-acids  are  formed  elsewhere  than  in  the 
liver. 

It  has  been  indubitably  proved  that  the  Ule-pigments  may  be 
formed  in  other  organs  besides  the  liver,  for,  as  is  generally 
admitted,  the  coloring  matter  htematoidin,  which  occurs  in  old 
blood  extravasations,  is  identical  with  the  bile-pigment  bilirubin 
(see  page  145),  Latschexbeeger  ^  has  also  observed  in  horses, 
under  pathological  conditions,  a  formation  of  bile-pigments  from 
the  blood-coloring  matters  in  the  tissues.  Also  the  occurrence  of 
bile-pigments  in  the  placenta  seems  to  depend  on  their  formation 
in  that  organ,  while  the  occurrence  of  small  quantities  of  bile-pig- 
ments in  the  blood-serum  of  certain  animals  probably  depends  on 
an  absorption  of  the  same. 

Although  the  bile-pigments  may  be  formed  in  other  organs 
besides  the  liver,  still  it  is  of  first  importance  to  know  what  bearing 
this  organ  has  on  the  elimination  and  formation  of  bile-pigments, 

'  Kallmeyer,   Ueber  die  Entsteliung  der  Gallensauren,  etc."     Inaug.  Diss. 
Dorpat,  1889. 

'  Zeitsclir.  f.  physiol.  Claem.,  Bd.  18.     This  contains  tlie  older  literature, 
»  Malv's  Jahresber.,  Bd.  16,  S.  301,  and  Monatshefte  f.  Chem.,  Bd.  0. 


244  TEE  LIVER. 

In  this  regard  it  must  be  recalled  that  the  liver  is  an  excretory- 
organ  for  the  bile-pigments  circulating  in  the  blood.  Taecha- 
liTOFF  *  has  observed,  in  a  dog  with  biliary  fistula,  that  intravenous 
injection  of  bilirubin  causes  a  very  considerable  increase  in  the  bile- 
pigments  eliminated.  This  statement  has  been  confirmed  lately  by 
the  investigations  of  Vossius.^ 

Numerous  experiments  have  been  made  to  decide  the  question 
whether  the  bile-pigments  are  only  eliminated  by  the  liver  or 
whether  they  are  also  formed  therein.  By  experimenting  on 
pigeons  Stern"  ^  was  able  to  detect  bile-pigments  in  the  blood-serum 
five  hours  after  tying  the  biliary  passages  alone,  while  after  tying 
all  the  vessels  of  the  liver  and  also  the  biliary  passages  no  bile- 
pigments  could  be  detected  either  in  the  blood  or  the  tissues  of  the 
animal,  which  was  killed  10-12  hours  after  the  operation.  Miisr- 
KOWSKi  and  NAUisrYisr  *  have  also  found  that  poisoning  with 
arseniuretted  hydrogen  produces  a  liberal  formation  of  bile-pigments 
and  the  secretion,  after  a  short  time,  of  a  urine  rich  in  biliverdin  in 
previously  healthy  geese.  In  geese  with  extirpated  livers  this  does 
not  occur. 

No  such  experiments  can  be  carried  out  on  mammalia,  as  they 
do  not  live  long  enough  after  the  operation;  still  there  is  no  doubt 
that  this  organ  is  the  chief  seat  of  the  formation  of  bile-pigments 
under  physiological  conditions. 

In  regard  to  the  materials  from  which  the  bile-acids  are  pro- 
duced, it  may  be  said  with  certainty  that  the  two  components, 
glycocoll  and  taurin,  which  are  both  nitrogenized,  are  formed  from 
the  protein  bodies.  In  regard  to  the  origin  of  the  non-nitrogenized 
cholalic  acid,  which  was  formerly  considered  as  originating  from 
the  fats,  we  know  nothing  positively. 

The  blood-coloring  matters  are  considered  as  the  mother-sub- 
stance of  the  bile-pigments.  If  the  identity  of  haematoidin  and 
bilirubin  was  settled  beyond  a  doubt,  then  this  view  might  be  con- 
sidered as  proved.  Independently,  however,  of  this  identity,  which 
is  not  admitted  by  all  investigators,  the  view  that  the  bile-pigments 
are  derived  from  the  blood-coloring  matters  has  strong  arguments 
in  its  favor.     It  has  been  shown  by  several  experimenters  that  a 

1  Pfluger's  Arch. ,  Bd.  9. 

*  Cit.  from  Stadelroanri,  Der  Icterus,  etc. 
3  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  19. 

*  Ibid.,  Bd.  21 


FORMATION  OF  BILE  PIGMENTS.  245 

yellow  or  yellowish-red  pigment  can  be  formed  from  the  blood- 
coloring  matters,  which  gives  Gmelijst's  test,  and  which,  though  it 
may  not  form  a  complete  bile-pigment,  is  at  least  a  step  in  its 
formation  (LATSCHE]srBER(iER  ').  A  further  proof  of  the  formation 
of  the  bile-pigments  from  the  blood -coloring  matters  consists  in  the 
fact  that  hfematin  yields  urobilin,  which  is  identical  with  hydro- 
bilirubin,  on  reduction  (Hoppe-Seyler  and  others).  Other  inves- 
tigators (Nencki  and  Sieber  and  Le  Nobel '^)  claim  that  the 
substance  thus  obtained  is  not  true  urobilin,  but,  all  things  consid- 
ered, it  seems  to  be  so  very  nearly  related  that  this  relationship  can 
be  considered  as  a  proof  of  the  formation  of  bilirubin  from  blood- 
pigments.  Further,  hasmatoporphyrin  (see  page  144)  and  bilirubin 
are  isomers,  according  to  Nencki  and  Sieber,  and  nearly  allied. 
The  formation  of  bilirubin  from  the  blood-coloring  matters  is 
shown,  according  to  the  observations  of  several  investigators,'  by 
the  appearance  of  free  hsemoglobin  in  the  plasma — produced  by  the 
destruction  of  the  red  corpuscles  by  widely  differing  influences  (see 
below)  or  by  the  injection  of  haemoglobin  solution — causing  an 
increased  formation  of  bile-pigments.  The  amount  of  pigments  in 
the  bile  is  not  only  considerably  increased,  but  the  bile-pigments 
may  even  pass  into  the  urine  under  certain  circumstances  (icterus). 
After  the  injection  of  haemoglobin  solution  into  a  dog  either  subcu- 
taneously  or  in  the  peritoneal  cavity,  Stadelman^^  and  Goro- 
decki  ^  observed  in  the  secretion  of  pigments  by  the  bile  an  increase 
of  Qlfo  which  lasted  for  more  than  twenty-four  hours. 

If,  then,  iron-free  bilirubin  is  derived  froLx  the  ha?matin  con- 
taining iron,  then  iron  must  be  split  off.  This  process  may  be 
represented  by  the  following  formula,  according  to  Nekcki  and 
Sieber,* 

C3.H3,N,0,Fe  +  2H,0  -  Fe  =  3C,.H,,N,03, 

though  in  reality  it  is  probably  more  complicated.  The  question 
in  what  form  or  combination  the  iron  is  split  off  is  of  special 
interest,  and  also  whether  it  is  eliminated  by  the  bile.  This  latter 
does  not  seem  to  be  the  case.  In  100  parts  of  bilirubin  which  are 
eliminated  by  the  bile  there  are  only  1.4-1.5  parts  iron,  according 

'  L.  c. 

'  See  Chapter  VI  on  the  blood,  p.  144. 

*  See  Stadelmann,  Der  Icterus,  etc. 

*  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  24. 


246  THE  LI7EB. 

to  KuifKEL  * ;  while  100  parts  liaematin  contain  about  9  parts  iron^ 
MiiiTKOWSKi  and  Baseeizst^  have  also  found  that  the  abundant 
formation  of  bile-pigments  occurring  in  poisoning  by  arseniu'retted 
hydrogen  does  not  increase  the  quantity  of  iron  in  the  bile.  The 
quantity  apparently  does  not  correspond  with  that  in  the  decom- 
posed blood-coloring  matters. 

On  the  contrary,  it  seems  as  if  the  iron,  at  least  for  a  time,  is 
retained  by  the  liver  as  a  pigment  rich  in  iron.  Such  a  pigment 
containing  iron,  which  was  formed  by  the  decomposition  of  haemo- 
globin,, was  observed  by  Nauntk  and  Miistkowski  ^  in  the  livers  of 
birds,  in  arseniuretted  hydrogen  icterus.  Latschenberger  * 
claims  that  a  yellow  or  yellowish-red  pigment,  "  choleglohin,''''  is 
derived  from  the  blood-coloring  matters,  and  acts  as  a  step  in  the 
formation  of  the  bile-pigments;  and  besides  this  he  mentions 
another  body  consisting  of  dark  grains  and  containing  iron,  which 
he  designates  as  melanin.  ISTEUMAi^Jsr  ^  has  observed  in  blood 
extravasations  and  thrombi,  besides  hsematoidin,  a  pigment  con- 
taining iron,  for  which  he  has  proposed  the  name  hcematosideriii. 

What  relationship  does  the  formation  of  bile-acids  bear  to  the 
formation  of  bile-pigments  ?  Are  these  two  chief  constituents  of 
the  bile  derived  simultaneously  from  the  same  material,  and  can  we 
detect  a  certain  connection  between  the  formation  of  bilirubin  and 
bile-acids  in  the  liver  ?  The  investigations  of  Stadelmann  '  teach, 
us  that  this  is  not  the  case.  With  increased  formation  of  bile- 
pigments  the  bile-acids  decrease  and  the  supply  of  hgemoglobin  to 
the  liver  acts  in  strongly  increasing  the  formation  of  bilirubin,  but 
simultaneously  strongly  decreases  the  production  of  bile-acids. 
According  to  STADELMANisr  the  formation  of  bile-pigments  and  bile- 
acids  is  due  to  a  special  activity  of  the  cells. 

An  absorption  of  bile  from  the  liver  by  the  lymphatic  vessels 
and  the  passage  of  the  bile  constituents  into  the  blood  and  urine 
occurs  in  retarded  discharge  of  the  bile,  and  usually  in  different 
forms  of  hepatogenic  icterus.  But  bile-pigments  may  also  pass  into 
the  urine  under  other  circumstances,  especially  in  animals  where  a 

1  Pflilger's  Arch.,  Bd.  14,  S.  353. 

»  ArcL.  f.  exp.  Path.  u.  Pharm.,  Bd.  23. 

*L.  c. 

« lUd. 

*  Virchow's  Arch.,  Bd.  111. 

'  Der  Icterus,  etc. 


BTLE  CONCBEMENTS.  247 

solution  or  destruction  of  the  red  blood-corpuscles  takes  place 
through  injection  of  water  or  a  solution  of  biliary  salts,  through, 
poisoning  by  ether,  chloroform,  arseniuretted  hydrogen,  phosphorus, 
or  toluylendiamin ;  and  in  other  cases.  This  occurs  also  in  man  in 
grave  infectious  diseases.  We  have  therefore  a  second  form  of 
icterus,  in  which  the  blood-coloring  matters  are  transformed  into 
bile-pigments  elsewhere  than  in  the  liver,  namely,  in  the  blood — a 
hmmatogenic  or  anhepatogenic  icteriis.  The  occurrence  of  a  hsema- 
togenic  icterus  has  been  made  very  probable  by  the  investigations 
of  Minkowski  and  NauisTtn,  Afaistassiew,  Silbermann",  and 
especially  Stadelmanist.  '  This  statement  has  been  proven  in  cer- 
tain of  the  above-mentioned  cases,  as  after  poisoning  with  phos- 
phorus, toluylendiamin,  and  arseniuretted  hydrogen,  by  direct 
experiment. 

The  icterus  is  also  in  these  cases  heptogenic;  it  depends  upon 
an  absorption  of  bile-pigments  from  the  liver,  and  this  absorption 
seems  to  originate  in  the  different  cases  in  somewhat  different  ways. 
Thus  the  bile  may  be  viscous  and  cause  a  stowing  of  the  bile  by 
counteracting  the  low  secretion  pressure.  In  other  cases  the  fine 
biliary  passages  may  be  compressed  by  an  abnormal  swelling  of  the 
liver-cells,  or  a  catarrh  of  the  bile-passages  may  occur  causing  a 
stowage  of  the  bile  (Stadelmann").  The  other  forms  of  so-called 
hsematogenic  icterus  are  now  explained  in  an  analogous  way. 

Bile  Concretions. 

The  concrements  which  occur  in  the  gall-bladder  vary  consider- 
ably in  size,  form,  and  number,  and  are  of  three  kinds,  depending 
upon  the  kind  and  nature  of  the  bodies  forming  their  chief  mass. 
One  group  of  gall-stones  contains  lime-pigment  as  chief  constituent, 
the  other  cholesterin,  and  the  third  calcium  carbonate  and  phos- 
phate. The  concrements  of  the  last-mentioned  group  occur  very 
seldom  in  man.  The  so-called  cholesterin  stones  are  those  which 
occur  most  frequently  in  man,  while  the  lime-pigment  stones  are 
not  found  very  often  in  man,  but  often  in  oxen. 

The  pigment-stones  are  generally  not  large  in  man,  but  in  oxen 
and  pigs  they  are  sometimes  found  the  size  of  a  walnut  or  even 
larger.     In  most  cases  they  consist  chiefly  of  bilirubin-calcium  with 

>  Tlie   literature   belonging  to   this   subject   is   found  in  Stadelmann,  Der 
Icterus;  etc.  Siuttgart,  1891. 


248  THE  LIVER. 

little  or  no  biliverdin.  Sometimes  also  small  black  or  greenish 
black,  metallic-looking  stones  are  found,  which  consist  chiefly  of 
bilifuscin  along  with  biliverdin.  Iron  and  copper  seem  to  be 
regular  constituents  of  pigment-stones.  Manganese  and.  zinc  have 
also  been  found  a  few  cases.  The  pigment-stones  are  generally 
heavier  than  water. 

The  cJwIesterin-stones,  whose  size,  form,  color,  and  structure 
may  vary  greatly,  are  often  lighter  than  water.  The  fractured 
surface  is  radiated,  crystalline,  and  frequently  shows  crystalline, 
concentric  layers.  The  cleavage  fracture  is  waxy  in  appearance, 
and  the  fractured  surface  when  rubbed  by  the  nail  also  becomes  like 
wax.  By  rubbing  against  each  other  in  the  gall-bladder  they  often 
become  faceted  or  take  other  remarkable  shapes.  Their  surface  is 
sometimes  nearly  white  and  waxlike,  but  generally  their  color  is 
variable.  They  are  sometimes  smooth,  in  other  cases  they  are 
rough  or  uneven.  The  quantity  of  cholesterin  in  the  stones  varies 
from  642-981  p.  m.  (Kittek').  The  cholesterin-stones  also  some- 
times contain  variable  amounts  of  lime-pigments  which  give  them 
a  very  changeable  appearance. 

Cholesterin,  C^^H^^O,  or,  according  to  Obermullee,  C„H^^0. 
Cholesterin  is  generally  considered  as  a  monatomic  alcohol  of  the 
formula  C^Jl^^.OIL.  According  to  the  investigations  of  Obee- 
]yiULLER,^  who  has  analyzed  several  cholesterin  compounds,  it  seems 
that  the  formula  is  rather  C^iH^^OH.  It  yields  a  colored  hydro- 
carbon, cholesterilin^  with  concentrated  sulphuric  acid,  and  this 
hydrocarbon  is  claimed  by  Weyl  ~  to  be  closely  related  to  the 
terpene  group.  Cholesterin  is  also  claimed  to  be  closely  allied  to 
cholalic  acid. 

Cholesterin  occurs  in  small  amounts  in  nearly  all  animal  fluids 
and  juices.  It  occurs  only  rarely  in  the  urine,  and  then  in  very 
small  quantities.  It  is  also  found  in  the  different  tissues  and 
organs — especially  abundant  in  the  brain  and  the  nervous  system, 
— further  in  the  yolk  of  the  egg,  in  semen,  and  in  wool-fat  (together 
with  isocholesterin).  It  appears  also  in  the  contents  of  the  intes- 
tine, in  excrements,  and  in  the  meconium.  It  occurs  pathologi- 
cally especially  in  gall-stones,  as  well  as  in  atheromatous  cysts,  in 
pus,  in  tuberculous  masses,  old  transudations,  cystic  fluids,  sputum, 

'  Journal  de  I'anat.  et  de  la  physiol.,  1873. 

'  Du  Bois-Reymond's  Arch.,  1889,  and  Zeitschr.  f.  physiol.  Chem,,  Bd.  15. 

*  Ibid.,  1886,  S.  183. 


CHOLESTERIN.  249 

and  tumors.     Several  kinds  of  cliolesterin  seem  to  occur  in  the 
plant  world, 

Cliolesterin  which  crystallizes  from  warm  alcohol  on  cooling, 
and  that  which  is  present  in  old  transudations,  contains  1  mol.  of 
water  of  crystallization,  melts  at  145°  C,  and  forms  colorless,  trans- 
parent plates  whose  sides  and  angles  frequently  appear  broken  and 
whose  acute  angle  is  often  76°  30'  or  87°  30'.  In  large  quantities 
it  appears  as  a  mass  of  white  plates  which  shine  like  niother-of-i:)earl 
and  have  a  greasy  feel. 

Cholesterin  is  insoluble  in  water,  dilute  acids  and  alkalies.  It 
is  neither  dissolved  nor  changed  by  boiling  caustic  alkali.  It  is 
easily  soluble  in  boiling  alcohol,  and  crystallizes  on  cooling.  It  dis- 
solves readily  in  ether,  chloroform,  and  benzol,  and  also  in  the 
volatile  or  fatty  oils.  It  is  dissolved  to  a  slight  extent  by  alkali 
salts  of  the  bile-acids. 

Among  the  many  combinations  of  cholesterin  studied  by  Ober- 
MULLER  ^  the  propionic  ester,  C,H^,CO.O.C^,H^.,  is  of  sjiecial 
interest.  This  is  used  in  the  detection  of  cholesterin.  For  the 
detection  of  cholesterin  we  make  use  of  its  reaction  with  concen- 
trated sulphuric  acid,  which,  as  above  stated,  gives  a  colored  hydro- 
carbon with  this  acid. 

If  a  mixture  of  five  parts  sulphuric  acid  and  one  part  water  acts 
on  a  cholesterin  crystal,  this  crystal  will  show  colored  rings,  first  a 
bright  carmine-red  and  then  violet.  This  fact  is  made  use  of  in 
the  microscopic  detection  of  cholesterin.  Another  test,  and  one 
very  good  for  the  microscopical  detection  of  cholesterin,  consists  in 
treating  the  crystals  first  with  the  above  dilute  acid  and  then  with 
some  iodine  solution.  The  crystals  will  be  gradually  colored  violet, 
bluish  green,  and  a  beautiful  blue. 

Salkowski's"  Reaction. — The  cholesterin  is  dissolved  in  chloro- 
form and  then  treated  with  an  equal  volume  of  concentrated  sul- 
phuric acid.  The  cholesterin  solution  becomes  first  bluish  red, 
then  gradually  more  violet-red,  while  the  sulphuric  acid  appears 
dark  red  witb  a  greenish  fluorescence.  If  the  chloroform  solution 
is  j)oured  into  a  porcelain  dish  it  becomes  violet,  then  green,  and 
finally  yellow. 

Liebermanx-Burchard's  '  Reaction. — Dissolve  the  cholesterin 

'L.  c. 

«  Pfiuger's  Arch.,  Bd.  6. 

»  C.  Liebermann,  Ber.  d.  deutsch.  cliem.  Gesellsch.,  Bd.   18,   S.  1805.     H. 
Burchard,  Beitrage  zur  KenntQiss  der  Cholesterine.    Rostock,  1889. 


250  THE  LIVEB. 

in  about  2  c.c.  chloroform  and  add  first  10  drops  acetic  anhy- 
dride and  then  concentrated  sulphuric  acid  drop  by  drop.  The 
mixture  will  first  be  beautiful  red,  then  blue,  and  finally,  if  not  too 
much  cholesterin  or  sulphuric  acid  is  present,  a  permanent  green. 
In  the  presence  of  very  little  cholesterin  the  green  color  may 
appear  immediately. 

Pure,  dry  cholesterin  when  fused  in  a  test-tube  over  a  low  flame  with  2  to 
3  drops  propionic  anhydride  yields  a  mass  which  on  cooling  is  first  violet,  then 
blue,  green,  orange,  carmine  red,  and  finally  copper-red.  It  is  best  to  re-fuse 
the  mass  on  a  glass  rod  and  then  to  observe  the  rod  on  cooling,  holding  it 
against  a  dark  background  (Oeermuller).' 

Schipf's  Reaction.  If  a  little  cholesterin  is  placed  in  a  porcelain  dish  with 
the  addition  of  a  few  drops  of  a  mixture  of  two  to  three  vols.  cone,  hydrochloric 
acid  or  sulphuric  acid  and  one  vol.  of  a  medium  solution  of  ferric  chloride,  and 
carefully  evaporated  to  dryness  over  a  small  flame,  a  reddish- violet  residue  is 
first  obtained  and  then  a  bluish  violet. 

If  a  small  quantity  of  cholesterin  is  evaporated  to  dryness  with  a  drop  of 
concentrated  nitric  acid,  we  obtain  a  yellow  spot  which  becomes  deep  orange- 
red  with  ammonia  or  caustic  soda  (not  a  characteristic  reaction). 

Isocholesterin.  This  body,  so  called  by  Schulze,'-'  is  isomeric  with  the 
ordinary  cholesterin  and  occurs  in  wool-fat,  and  is  therefore  found  in  abundant 
quantities  in  so-called  lanolin.  It  does  not  give  Salkowski's  reaction.  It 
melts  at  138-138°. 5. 

We  make  use  of  the  so-called  cholesterin-stones  in  the  prepara- 
tion of  cholesterin.  The  powder  is  first  boiled  with  water  and  theL. 
repeatedly  boiled  with  alcohol.  The  cholesterin  which  on  cooling 
separates  from  the  warm  filtered  solution  is  boiled  with  a  solution 
of  caustic  potash  in  alcohol  so  as  to  saponify  any  fat.  After  th( 
evaporation  of  the  alcohol  we  extract  the  cholesterin  from  the 
residue  with  ether,  by  which  the  soaps  are  not  dissolved,  filter, 
evaporate  the  ether,  and  purify  the  cholesterin  by  recrystallization 
from  alcohol-ether.  The  cholesterin  may  be  extracted  from  tissues 
and  fluids  by  first  extracting  with  ether  and  then  purifying  as 
above. 

It  is  detected  and  determined  quantitatively  in  tissue,  etc.,  by 
this  same  method.  It  is  ordinarily  easily  detected  in  transudations 
and  pathological  formations  by  means  of  the  microscope. 

1  L.  c. 

2  Ber.  d.  deutsch.  chem.  Gesellch.,  Bd.  6;  Journal  f.  prakt.  Chem.,  N.  F. 
Bd.  25,  S.  458;  and  Zeitschr.  f.  physiol.  Chem.,  Bd.  14,  S.  533.  See  also  E. 
Schulze  and  J.  Barbieri,  Journal  f.  prakt.  Chem.,  N.  F.  Bd.  35,  S.  159. 


CHAPTER  IX. 

DIGESTION. 

The  purpose  of  the  digestion  is  to  separate  those  constituents 
of  t]ie  food  which  serve  as  the  nutriment  of  the  body  from  those 
which  are  useless,  and  to  sejoarate  each  in  such  a  form  that  it  may 
be  taken  up  by  the  blood  from  the  alimentary  canal  and  employed 
for  the  various  purposes  in  the  organism.  This  demands  not  only 
mechanical  but  also  chemical  action.  The  first  action,  which  is 
essentially  dependent  upon  the  physical  properties  of  the  food,  con- 
sists in  a  tearing,  cutting,  crushing,  or  grinding  of  the  food,  and 
serves  chiefly  to  convert  the  nutritive  bodies  into  a  soluble  and 
easily  absorbed  form,  or  in  the  splitting  of  the  same  into  simpler 
combinations  for  use  in  the  animal  synthesis.  The  solution  of  the 
nutritive  bodies  may  take  place  in  certain  cases  by  the  aid  of  water 
alone,  but  in  most  cases  a  chemical  metamorjDhosis  or  splitting  is 
necessary,  and  is  effected  by  means  of  the  acid  or  alkaline  fluids 
secreted  by  the  glands.  The  study  of  the  processes  of  digestion 
from  a  chemical  standpoint  must  therefore  begin  with  the  digestive 
fluids,  their  qualitative  and  quantitative  composition,  as  well  as 
their  action  on  the  nutriments  and  foods. 

I.  The  Salivary  Glands  and  the  Saliva. 

The  salivary  glands  are  i^artly  alMiminous  glands  (as  the  parotid 
in  man  and  mammalia  and  the  submaxillary  in  rabbits),  partly 
mucous  glands  (as  some  of  the  small  glands  in  the  buccal  cavity  and 
the  sublingual  and  submaxillary  glands  of  many  animals),  and 
partly  mixed  glands  (as  the  submaxillary  gland  in  man).  The 
alveoli  of  the  albumin-glands  contain  cells  which  are  rich  in 
albumin,  but  contain  no  mucin.  The  alveoli  of  the  mucin-glands 
contain  cells  rich  m  mucinogen  or  mucin  but  poor  in  albumin. 

251 


2-32  DIOESTION. 

Cells  rich  in  proteid  also  occur  in  the  submaxillary  and  sublingual 
glands  between  the  mucous  cells  and  tbe  membrana  propria,  which. 
in  a  few  cases  takes  the  form  of  a  crescent  (lunula,  according  to 
Glanuzzi),  and  in  other  cases  the  cells  rich  in  mucin  are  sur- 
rounded as  by  a  ring,  and  sometimes  certain  alveoli  may  be  com- 
pletely filled.  By  continuous  secretion  the  mucin-cells  seem  to  give 
up  all  their  mucin  (Ewald,  Stohr),  so  that  only  albumin-cells  are 
to  be  seen  (Heidenhain  ').  During  rest  the  mucin  is  re-formed. 
According  to  the  analyses  of  Oidtmann  ^  the  salivary  glands  of  a 
dog  contain  790  p.  m.  water,  200  p.  m.  organic  and  10  p.  m. 
inorganic  solids. 

Among  the  solids  we  find  mucin,  pi^oteids,  amongst  which 
nucleoalhumin  or  nucleoproteid,  miclein,  diastatic  enzyme  and  its 
zymogen,^  besides  exh'active  bodies,  leucin,  xanthin  bases,  and 
mineral  substances. 

The  saliva  is  a  mixture  of  the  secretion  of  the  above-mentioned 
groups  of  glands ;  therefore  it  is  proper  that  we  first  study  each  of 
the  different  secretions  by  itself,  and  then  the  mixed  saliva. 

The  submaxillary  saliva  in  man  may  be  easily  collected  by  intro- 
ducing a  canula  through  the  papillary  opening  into  Wharton's  duct. 

The  submaxillary  saliva  has  not  always  the  same  composition  or 
properties;  this  depends  essentially  upon  the  conditions  under 
which  the  secretion  takes  place.  That  is  to  say,  the  secretion  is 
partly  dependent  on  the  cerebral,  partly  on  the  sympathetic,  ner- 
vous system.  In  consequence  of  this  dependence  the  two  distinct 
varieties  of  submaxillary  secretion  are  distinguished  as  cliorda-  and 
sympathetic  saliva.  A  third  kind  of  saliva,  the  so-called  paralytic 
saliva,  is  secreted  after  poisoning  with  curara  or  after  the  severing 
of  the  glandular  nerves. 

The  difference  between  chorda-  and  sympathetic  saliva  (in  dogs) 
consists  chiefly  in  their  quantitative  constitution,  namely,  the  less 
abundant  sympathetic  saliva  is  more  viscous  and  richer  in  solids, 
especially  in  mucin,  than  the  more  abundant  chorda-saliva.  The 
specific  gravity  of  the  chorda-saliva  of  the  dog  is  1.0039-1.0056  and 

'  In  regard  to  these  conditions  see  text-books  on  histology  and  the  article 
"Die  Absonderungsvorgange  "  by  Heidenhain  in  Hermann's  Handbuch  der 
Physiologie,  Bd.  5,  S.  57. 

*  Cit.  from  Gorup  Besanez,  Lehrbuch  d.  physiol.  Chem.,  4.  Aufl.,  S.  732. 
The  figures  there  given  amount  to  1010  parts  instead  of  1000  parts. 

2  See  especially  Warren,  Centralbl.  f.  Physiol.,  Bd.  8,  S.  211. 


SALIVA.  2.33 

contains  from  12-14  p.  m.  solids  (Eckhard').  The  sympathetic 
has  a  specific  gravity  of  1.0075-1.018,  witli  16-28  p:  m,  solids. 
The  gases  of  the  chorda-saliva  have  been  investigated  by  Pfluger.* 
He  found  0.5-0.8,^  oxygen,  0.9-1^  nitrogen,  and  64.73-85.13^ 
carbon  dioxide — all  results  calculated  at  0°  C.  and  760  mm.  pres- 
sure. The  greater  part  of  the  carbon  dioxide  was  chemically  com- 
bined. 

The  two  kinds  of  submaxillary  secretion  Just  named  have 
not  thus  far  been  separately  studied  in  man.  The  secretion 
may  be  excited  by  a  moral  emotion,  by  mastication,  and  by 
irritating  the  mucous  membrane  of  the  mouth,  especially  with, 
acid-tasting  substances.  The  submaxillary  saliva  in  man  is  ordi- 
narily clear,  rather  thin,  a  little  ropy,  and  froths  easily.  Its  reac- 
tion is  alkaline.  The  specific  gravity  is  1.002-1.003,  and  it 
contains  3.6-4.5  p.  m.  solids.'  We  find  as  organic  constituents 
mucin,  traces  of  proteid  and  diastatic  enzyme,  which  is  absent  in 
several  species  of  animals.  The  inorganic  bodies  are  alkali  chlorides, 
sodium  and  magnesium  phosphates,  besides  bicarbonates  of  the 
alkalies  and  calcium.  Oehl^  finds  0.036  p.  m.  potassium  sulpho- 
cyanide  in  this  saliva. 

The  Suhlingual  Saliva. — The  secretion  of  this  saliva  is  also 
influenced  by  the  cerebral  and  the  sympathetic  nervous  system. 
The  chorda-saliva,  which  is  secreted  only  to  a  small  extent,  con- 
tains numerous  salivary  corpuscles,  but  is  otherwise  transparent  and 
very  ropy.  Its  reaction  is  alkaline  and  contains,  according  to 
Heidenhain,'  27.5  p.  m.  solids  (in  dogs). 

The  sublingual  secretion  in  man  has  been  investigated  by 
Oehl."  It  was  clear,  mucilaginous,  more  alkaline  than  the  sub- 
maxillary saliva,  and  contained  mucin,  diastatic  enzyme,  and  potas- 
sium sulphocyanide. 

Buccal  mucus  can  only  be  obtained  pure  from  animals  by  the 
method  of  Bidder  and  Schmidt,  which  consists  in  tying  the  exit 
to  all  the  large  salivary  glands  and  cutting  off  their  secretion  from 
the  mouth.     The  quantity  of  liquid  secreted  under  these  circum- 

'  Cit.  from  Kiiline,  Lelirb.  d.  physiol.  Chem. ,  S.  7. 
3  Pfliiger's  Arch.  Bd.  1. 

^  See   Maly,    Chemie   der  Verdauungssafte  und    der   Verdauung    in  Her- 
mann's Handb.,  Bd.  5,  Th.  2,  S.  18. 

*  Canstatfs  Jaliresbericht  d.  Med.,  1865,  1,  S.  120. 
5  Studien  d.  physiol.  Instituts  zu  Breslau,  Heft  4. 
»L.  c. 


254  BIOE8TI0N. 

stances  (in  dogs)  was  so  very  small  that  the  investigators  named 
were  able  to  collect  only  2  grms.  buccal  mucus  in  the  course  of 
twenty-four  hours.  It  is  a  thick,  ropy,  sticky  liquid  containing 
mucin;  it  is  rich  in  form-elements,  above  all  in  flat  epithelium- 
cells,  mucous  cells,  and  salivary  corpuscles.  The  quantity  of  solids 
in  the  buccal  mucus  of  the  dog  is,  according  to  Bidder  and 
Schmidt,^  9.98  p.  m. 

Parotid  Saliva.  The  secretion  of  this  saliva  is  also  partly 
dependent  on  the  cerebral  nervous  system  (n.  glossopharyngeus) 
and  partly  on  the  sympathetic.  The  secretion  may  be  excited  by 
mental  emotions  and  by  irritation  of  the  glandular  nerves,  either 
directly  (in  animals)  or  reflexly,  by  mechanical  or  chemical  irrita- 
tion of  the  mucous  membrane  of  the  mouth.  Among  the  chemical 
irritants  the  acids  take  first  place,  while  alkalies  and  pungent  sub- 
stances have  little  action.  Sweet-tasting  bodies,  such  as  honey,  are 
said  to  have  no  effect.  Mastication  has  great  influence  in  the  secre- 
tion of  parotid  saliva,  which  is  especially  marked  in  certain 
herbivora. 

Human  parotid  saliva  may  be  collected  by  the  introduction  of  a 
canula  into  Stenson''s  duct.  This  saliva  is  thin,  less  alkaline  than 
the  submaxillary  saliva  (the  first  drops  are  sometimes  neutral  or 
acid),  without  special  odor  or  taste.  It  contains  a  little  albumin 
but  no  mucin,  which  is  to  be  expected  from  the  construction  of  the 
gland.  It  also  contains  a  diastatic  enzyme,  which,  however,  is 
absent  in  many  animals.  The  quantity  of  solids  varies  between  5 
and  16  p.  m.  The  specific  gravity  is  1.003-1.012.  Potassium 
sulphocyanide  seems  to  be  present,  though  it  is  not  a  constant  con- 
stituent. KtJLz'  found  1.46^  oxygen,  3.2^  nitrogen,  and  in  all 
66.7^  carbon  dioxide  in  human  parotid  saliva.  The  quantity  of 
firmly  combined  carbon  dioxide  was  62^. 

The  mixed  buccal  saliva  in  man  is  a  colorless,  faintly  opalescent, 
slightly  ropy,  easily  frothing  liquid  without  special  odor  or  taste. 
It  is  made  turbid  by  epithelium-cells,  mucous  and  salivary  corpus- 
cles, and  often  by  food  residues.  Like  the  submaxillary  and  parotid 
saliva,  on  exposure  to  the  air  it  becomes  covered  with  an  incrusta- 
tion consisting  of  calcium  carbonate  and  a  small  quantity  of  an 
organic  substance,  or  it  gradually  becomes  cloudy.     Its  reaction  is 

-  Die  Verdauungssafte  nnd  der  StofEwechsel  (Mitau  and  Leipzig,  1852), 
S.  5. 

»  Zeitschr.  f .  Biologic,  Bd.  33. 


PTYALIN.  255 

alkaline,  but  occasionally  also  acid.  According  to  Sticker,'-  fresh 
saliva  may  be  acid  a  few  hours  after  a  meal.  Two  or  three  hoars 
after  breakfast  and  four  to  five  hours  after  dinner  the  maximum  of 
acidity  occurs,  and  it  may  also  be  faintly  acid  from  midnight  to 
morning.  The  specific  gravity  varies  between  1.002  and  1.008,  and 
the  quantity  of  solids  between  5  and  10  p.  m.  The  solids,  irre- 
spective of  the  form-constituents  mentioned,  consist  of  albumin, 
mucin,  'ptyalin,  and  mineral  bodies.  It  is  also  claimed  that  urea  is 
a  normal  constituent  of  the  saliva.  The  mineral  bodies  are  alkali 
chlorides,  bicarbonates  of  the  alkalies  and  calcium,  phosphates,  and 
traces  of  sulphates  and  sulphocyanides. 

Sulphocyanides,  which,  although  not  constant,  occur  in  the 
saliva  of  man  and  certain  animals,  may  be  easily  detected  by  first 
acidifying  the  saliva  with  hydrochloric  acid  and  treating  with  a  very 
dilute  solution  of  ferric  chloride.  To  make  the  test  more  conclusive 
it  is  best,  as  control,  to  take  an  equal  quantity  of  acidified  water 
and  then  add  ferric  chloride.  Another,  simpler  method,  proposed 
by  GscHEiDLEX,^  consists  in  putting  in  a  drop  or  two  of  the  saliva 
on  filter-paper  which  has  previously  been  dipped  in  an  amber- 
colored  solution  of  ferric  chloride  containing  hydrochloric  acid,  and 
then  di'ied.  Each  drop  of  saliva  containing  sulphocyauide  will 
give  a  reddish  spot.  If  the  quantity  of  sulphocyauide  is  so  small 
that  it  cannot  be  detected  directly,  concentrate  the  saliva  after 
the  addition  of  a  little  alkali,  acidify  strongly  with  hydrochloric 
acid,  and  shake  repeatedly  with  ether,  evaporating  the  latter  after 
the  addition  of  water  containing  alkali  over  a  gentle  heat;  then 
test  the  remaining  liquid. 

Ptyalin,  or  salivary  diastase,  is  the  amylolytic  enzyme  of  the 
saliva.  This  enzyme  is  found  in  human  saliva,  but  not  in  that  of 
all  animals.  It  occurs  not  only  in  adults,  but  also  in  new-born 
infants.  Zweifel  '  claims  that  the  ptyalin  in  new-born  infants 
occurs  only  in  the  parotid  gland,  but  not  in  the  submaxillary.  In 
the  latter  it  appears  only  two  months  after  birth. 

According  to  H.  Goldschhidt  ^  the  saliva  (parotid  saliva)  of 
the  horse  does  not  contain  ptyalin,  but  a  zymogen  of  the  same,  while 
in  other  animals  and  man  the  ptyalin  is  formed  from  the  zymogen 
during   secretion.      In   horses   the   zymogen   is   transformed    into 

»  Deutsch.  med.  Zeitung,  1889.  Cit.  from  Centralbl.  f.  Physiol.,  Bd.  3,  S.  237. 
*  Maly's  Jahresber.,  Bd.  4,  S.  91. 

3  Untersuchungen  ilber  den  Verdauungsapparat  der  Neugeborenen.  Ber- 
lin, 1874. 

♦Zeitschr.  f.  physiol.  Chem.,  Bd.  10. 


256  DIGESTION. 

ptyalin  daring  mastication,  and  the  bacteria  seem  to  give  the 
impulse  to  this  change.  During  precipitation  with  alcohol  the 
zymogen  is  changed  into  ptyalin. 

Ptyalin  has  not  been  isolated  in  a  pure  form  up  to  the  present 
time.  It  can  be  obtained  purest  by  Cohnheim's  '  method,  which 
consists  in  carrying  the  enzyme  doAvn  mechanically  with  a  calcium- 
phosphate  precipitate  and  washing  the  precipitate  with  water,  which 
dissolves  the  ptyalin,  and  from  which  it  can  be  obtained  by  precipi- 
tating with  alcohol.  For  the  study  or  demonstration  of  the  action 
of  ptyalin  we  may  use  a  watery  or  glycerin  extract  of  the  salivary 
glands,  or  simj)ly  the  saliva  itself. 

Ptyalin,  like  other  enzymes,  is  characterized  by  its  action. 
This  consists  in  converting  starch  into  dextrin  and  sugar.  In 
regard  to  the  process  going  on  in  this  conversion  we  are  not  quite 
clear.  In  general  it  may  be  described  as  follows:  In  the  first  stages 
soluble  starch  or  amidulin  is  formed.  From  this  amidulin, 
erythrodextrin  and  sugar  are  produced  by  hydrolytic  cleavage. 
The  erythrodextrin  then  splits  into  «-achroodextrin  and  sugar. 
From  this  achroodextrin  by  splitting  /3-achroodextrin  and  sugar  are 
formed,  and  finally  this  y^-achroodextrin  splits  into  sugar  and  y- 
achroodextrin.  According  to  a  few  investigators  the  number  ol 
dextrins  formed,  as  intermediate  steps  is  different.  It  is  only  within 
a  very  short  time  that  we  have  been  made  clear  as  to  the  kind  of 
sugar  produced  in  this  process.  For  a  long  time  it  was  considered 
that  dextrose  was  the  sugar  formed  from  starch  and  glycogen,  but 
Seegen  "^  and  0.  Nasse  '  have  shown  that  this  is  not  true. 

MuscuLUS  and  v.  Meeing  "  have  shown  that  the  sugar  formed 
by  the  action  of  saliva,  amylopsin,  and  diastase  upon  starch  and 
glycogen  is  in  greatest  part  maltose.  This  has  been  substantiated 
by  Browin'  and  Heron.  '  Lately  E.  Kulz  and  J.  Vogel  '  have 
demonstrated  that  in  the  saccharification  of  starch  and  glycogen 
isomaltose,  maltose,  and  some  dextrose  are  formed,  the  varying 
quantities  depending  upon  the  amount  of  ferment  and  length  of 

'  Virchow's  Arch. ,  Bd.  28. 

2  Centralbl.  f.  d.  med.  Wissensch.,  1876,  S.  851,  and  PflUger's  Arch., 
Bd.  19. 

2  Pfliiger's  Arch.,  Bd.  14. 
^Zeitschr.  f.  physiol  Chem.,  Bd.  2. 
'  Liebig's  Annalen,  Bdd.  199  and  204. 
«  Zeitschr.  f.  Biologic,  Bd.  31. 


ACTION  OF  PTYALIN.  257 

time  of  digestion.  As,  according  to  Tebb,'  the  salivary  glands,  as 
well  as  the  jjancreas,  contain  an  inverting  enzyme,  it  is  still  un- 
decided whether  the  formation  of  dextrose  is  due  to  the  diastatic 
enzyme  or  to  the  invertin  alone.  According  to  Eohmann  and 
Hamburger  '  the  saliva  contains  diastase  and  glucase.  The  same 
is  true  for  the  pancreatic  juice  and  intestinal  juice.  In  relation  to 
the  blood-serum  all  these  secretions  are  relatively  poor  in  glucase, 
and  this  is  especially  true  for  saliva. 

Ptyalin  is  not,  identical  with  malt  diastase.  It  is  most  active  at 
about  -|-  40°  C,  wiiile,  according  to  Chittendejst  and  Martin,* 
LiNTNER,  and  Eckhard,*  malt  diastase  is  most  active  at  +  50°  to 
55°  C. 

The  action  of  ]3tyalin  in  various  reactions  has  been  the  subject 
of  numerous  investigations.^  Naturally  the  alkaline  saliva  is  very 
active,  but  it  is  not  as  active  as  when  neutral.  It  may  be  still  more 
active  under  circumstances  in  faintly  acid  reaction,  and  according  to 
Chittenden  and  Smith  it  acts  better  when  enough  hydrochloric 
acid  is  added  to  saturate  the  proteids  present  than  when  only  simply 
neutralized.  When  the  acid  combined  proteid  exceeds  a  certain 
amount,  then  the  diastatic  action  is  diminished.  The  addition  of 
alkali  to  the  saliva  decreases  its  diastatic  action;  on  neutralizing  the 
alkali  with  acid  or  carbon  dioxide  the  retarding  or  preventive  action 
of  the  alkali  is  arrested.  According  to  Schierbeck  carbon  dioxide 
has  an  accelerating  action  in  neutral  liquids,  while  Ebstein  claims 
that  it  has  as  a  rule  a  retarding  action.  Organic  as  well  as  inor- 
ganic acids,  when  addeif  in  sufficient  quantity,  may  stop  the  dias- 
tatic action  entirely.  The  degree  of  acidity  necessary  in  this  case 
is  not  always  the  same  for  a  certain  acid,  but  is  dependent  upon  the 
quantity  of  ferment.  The  same  degree  of  acidity  in  the  presence 
of  large  amounts  of  ferment  has  a  weaker  action  than  in  the  pres- 

'  Journal  of  Physiol.,  Vol.  15. 

'  Ber.  d.  deutscli.  chem.  Gesellsch.,  Bd.  27,  and  Pfliiger's  Arch.,  Bd.  60. 

*  Studies  from  the  Laborat.  of  Physiol.  Chem.  of  Yale  College,  Vol.  1,  1885. 

*■  Journ.  f.  prakt.  Chem.,  N.  F.  Bd.  41. 

5  See  Hammarsten,  Maly's  Jahresber.,  Bd.  1  ;  Chittenden  and  Grisvvold, 
ibid.,  Bd.  11  ;  Langley,  Journal  of  Physiol.,  Vol.  3  ;  Nylen,  Maly's  Jahresber., 
Bd.  12,  S.  241  ;  Chittenden  and  Ely,  ibid.,  S.  242  ;  Langley  and  Eves,  Jour- 
nal of  Physiol.,  Vol.  4  ;  Chittenden  and  Smith,  Yale  College  Studies,  Vol.  1, 
1885,  p.  1  ;  John,  Centralbl.  f.  klin.  Med.,  Bd.  12  ;  Schlesinger,  Virchow's 
Arch  ,  Bd.  125  ;  Shierbeck,  Skand.  Arch.  f.  Physiol.,  Bd.  3  ;  Ebstein  and  C. 
Schulze,  Virchow's  Arch.,  Bd.  134. 


258  DIGESTION. 

euce  of  smaller  quantities.  Hydrochloric  acid  is  of  special  physio- 
logical interest  in  this  regard,  namely,  it  prevents  the  formation  of 
sugar  even  ia  very  small  amounts  (0.03  p.  m.).  Hydrochloric  acid 
has  not  only  the  property  of  preventing  the  formation  of  sugar,  but, 
its  shown  by  Laistglet,  Ntle]s^,  and  others,  may  entirely  destroy 
the  enzyme.  This  is  important  in  regard  to  the  physiological  sig- 
nificance of  the  saliva.  That  boiled  starch  (paste)  is  quickly,  and 
unboiled  starch  only  slowly,  converted  into  sugar  is  also  of  in- 
terest. Various  kinds  of  unboiled  starch  are  converted  Avith 
different  degrees  of  rapidity. 

The  rapidity  with  which  ptyalin  acts  increases,  at  least  under 
conditions  otherwise  favorable,  with  the  amount  of  enzyme  and  with 
an  increasing  temperature  to  a  little  above  -\-  40°  C.  Foreign  sub- 
statices,  such  as  metallic  salts,  ^  have  different  effects.  Certain  salts 
even  in  small  quantities  completely  arrest  the  action;  for  example, 
HgCl^  accomplishes  this  result  by  the  presence  of  only  0.05  p.  m. 
Other  salts,  such  as  magnesium  sulphate,  in  small  quantities  (0.25 
23.  m.)  accelerate,  and  in  larger  quantities  (5  p.  m.)  check  the 
action.  The  presence  of  peptone  has  an  accelerating  action  on 
the  sagar  formation  (Chittendei^t  and  Smith  and  others).  The 
accumulation  of  the  products  of  the  amylolytic  decomposition  also 
checks  the  action  of  the  saliva.  This  has  been  shown  by  special 
experiments  made  by  Sh.  Lea.^  He  made  parallel  experiments 
with  digestions  in  test-tubes  and  in  dialyzers,  and  found  on  the 
removal  of  the  products  of  the  amylolytic  decomposition  by  dialysis 
that  the  formation  of  sugar  took  place  quicker,  but  also  that  consid- 
erably more  maltose  and  less  dextrin  was  formed. 

To  show  the  action  of  saliva  or  ptyalin  on  starch  the  three 
ordinary  tests  for  dextrose  may  be  used,  namely,  Moore's  or 
Tkommer's  test  or  the  bismuth  test  (see  Chapter  XV).  It  is  also 
necessary,  as  a  control,  to  first  test  the  starch-paste  and  the  saliva 
for  the  presence  of  dextrose.  The  steps  formed  in  the  transforma- 
tion of  starch  into  amidulin,  erythrodextrin,  and  achroodextrin  may 
be  shown  by  testing  with  iodine. 

The  quantitative  com2)Osition  of  the  mixed  saliva  must  vary  con- 
siderably, not  only  because  of  individual  differences,  but  also 
because  under  varying  conditions  there  may  be  an  unequal  division 

'  See  O.  Nasse,  Pflliger's  Arch.,  Bd.  11,  and  Chittenden  and  Painter,  Yale 
College  Studies,  Vol.  1,  1885,  p.  52. 
2  Journ.  of  Physiol.,  Bd.  11. 


COMPOSITION  OF  THE  SALIVA. 


259 


of  the  secretion  from  the  different  glands.  "We  give  below  a  few- 
analyses  of  human  saliva  as  example  of  its  composition.  The 
results  are  in  parts  per  1000. 


Water 

Solids  

Mucus  and  epithelium  .... 

Soluble  organic  substances . 

(Ptyalin  of  early  investigators) 

Sulpliocyanides 

Salts 


..; 

13 

-: 

N 
« 

CO 

o 
m 

Eh 

HI 

o 

B 

a 
o 
-<! 

1-3 

995.16 

oi 

n 
u 

% 

»  S  H 

a  =  a 
S    ^ 

PS 

£ 

< 
a 
ta 
a 
h5 

992.9 

994.1 

988.3 

994.7 

7.1 

4.84 

5.9 

11.7 

5.3 

3.5-8.4 

1.4 

1.62 

2.13 

in 
filtered 
saliva. 

3.8 

1.34 

1.42 

8.27 

0.06 

0.10 

0.064 
to 
0.09 

1.9 

1.82 

2.19 

1.03 

S  m 


994.2 
5.8 


2.2 

1.4 


0.04 


2.2 


Hajtsierbacher  found  in  lOOO  parts  of  the  ash  from  human  saliva:  potash 
457.2,  soda  95.9,  iron  oxide  50  11,  magnesia  1.55,  sulphuric  anhydride  (SOa) 
63.8,  phosphoric  anhydride  (P2O5)  188.48,  and  chlorine  183.52. 

The  quantity  of  saliva  secreted  during  2-4  hours  cannot  be 
exactly  determined,  but  has  been  calculated  by  Bidder  and 
Schmidt  *  to  be  1400-1500  grms.  The  most  abundant  secretion 
occurs  during  meal-times.  According  to  the  calculations  and 
determinations  of  Tuczek  ^  in  man,  1  grm.  of  gland  yields  13  grms. 
secretion  in  the  course  of  one  hour  during  mastication.  These 
figures  correspond  fairly  well  with  those  representing  the  average 
secretion  from  1  grm.  of  gland  in  animals,  namely,  14.2  grms.  in 
the  horse  and  8  grms.  in  oxen.  The  quantity  of  secretion  per  hour 
may  be  8  to  14  times  greater  than  the  entire  mass  of  glands,  and 
there  is  probably  no  gland  in  the  entire  body,  as  far  as  we  know  at 
present — the  kidneys  not  excepted — whose  ability  of  secretion  under 
physiological  conditions  equals  that  of  the  salivary  glands.  A 
remarkably  abundant  secretion  of  saliva  is  induced  by  pilocarpin, 
while  atropin,  on  the  contrary,  prevents  it. 

Though  an  abundant  secretion  of  saliva  is  produced,  as  a  rule, 

'  Zeitschr.  f.  physiol.  Chem.,  Bd.  5.  The  other  analyses  are  cited  from 
Maly,  Chemie  der  Verdauungssafte,  Hermann's  Handbuch  d.  Physiol.,  Bd.  5, 
Th.2,  S.  14. 

«  L.  c,  S.  13. 

3  Zeitschr.  f.  Biologie,  Bd.  12. 


260  BIQESTION. 

by  an  increased  supply  of  blood,  still  it  is  not  a  simple  filtration 
process,  as  seen  from  tlie  following  circumstances.  The  secretioa- 
pressure  is  greater  than  the  blood-pressure  in  the  carotid,  aad  in 
poisoning  by  atropin,  which  paralyzes  the  secretory  nerves,  an 
increased  supply  of  blood  is  produced  by  irritation  of  the  chorda, 
but  no  secretion.  The  salivary  glands  have  moreover  a  specific 
property  of  eliminating  certain  substances,  such  as  potassium  salts 
(Salkowski),'  iodine,  and  bromine  combinations,  but  not  others, 
such  as  iron  combinations.  It  is  also  noticeable  that  the  saliva  is 
richer  in  solids  when  it  is  eliminated  quickly  by  gradually  increased 
irritation,  and  in  larger  quantities  than  when  the  secretion  is  slower 
and  less  abundant  (Heidexhain")."  The  amount  of  salts  increases 
also  to  a  certain  degree  by  an  increasing  rapidity  of  elimination 
(Heidenhaik,  Werther,"  Langlet  and  Fletcher,*  ISTovi"). 

The  chemical  changes  taking  place  during  secretion  are  un- 
known, but  it  is  probable  that,  like  the  secretion  processes  in 
general,  the  secretion  of  saliva  is  closely  connected  with  the  pro- 
cesses in  the  cells.  The  chemical  processes  going  on  in  these  cells 
during  secretion  are  still  unknown,  Heidenhain  claims  that  the 
mucin  cells  of  the  submaxillary  gland  are  destroyed  during  secretion, 
and  in  the  period  of  rest  the  mucin  or  mucinogen  reappears  in  these 
cells.  EwALD "  claims  that  they  only  discharge  their  mncin. 
These  observations  still  do  not  throw  any  light  upon  the  chemical 
processes  going  on. 

The  Physiological  Importance  of  the  Saliva.  The  quantity  of 
water  in  the  saliva  renders  possible  the  effects  of  certain  bodies  on 
the  organs  of  taste,  and  it  also  serves  as  a  solvent  for  a  part  of  the 
nutritive  substances.  The  importance  of  the  saliva  in  mastication 
is  especially  marked  in  herbivora,  and  there  is  no  question  of  its 
importance  in  facilitating  the  act  of  swallowing.  The  power  of 
converting  starch  into  sugar  does  not  belong  to  the  saliva  of  all 
animals,  and  even  when  it  possesses  this  property  the  intensity 
varies  in  different  animals.  In  man,  whose  saliva  forms  sugar 
rapidly,  a  formation  of  sugar  from  (boiled)  starch  undoubtedly  takes 
place  in  the  mouth,  but  how  far  this  action  goes  on  after  the  morsel 

'  Vircliow's  Arch.,  Bd.  53. 

5  Pflliger's  Arch.,  Bd.  17. 

3  Ibid.,  Bd.  38. 

••  Proc.  Roy.  Soc,  Vol.  45,  and  especially  Philos.  Trans.,  Vol.  180, 

5  Du  Bois-Reymond's  Arch.,  1888. 

*  See  Heidenhain  in  Hermann's  Ha,ndb.,  Bd.  5,  Th.  1,  S.  64,  etc. 


GLANDS   OF  THE  STOMACH.  261 

has  entered  the  stomach  depends  upon  the  rapidity  with  which  the 
acid  gastric  jnice  mixes  with  the  swallowed  food,  and  also,  upon  the 
relative  amounts  of  the  gastric  juice  and  food  in  the  stomach.  The 
large  quantity  of  water  which  is  swallowed  with  the  saliva  must  be 
absorbed  and  pass  into  the  blood,  and  it  must  go  through  an* 
intermediate  circulation  in  the  organism.  Thus  the  organism 
possesses  in  the  saliva  an  active  medium  by  which  a  constant 
stream,  conveying  the  dissolved  and  finely  divided  bodies,  passes 
into  the  blood  from  the  intestinal  canal  during  digestion. 

Salivary  Concrements.  The  so-called  tartar  is  yellow,  gray,  yellowish  gray, 
brown  or  Ijlack,  and  has  a  stratified  structure.  It  may  contain  more  than  200 
p.  m.  organic  substances,  which  consist  of  mucin,  epithelium,  and  lepto- 
THRix-CHAiNS.  The  chief  part  of  the  inorganic  constituents  consists  of  calcium 
carbonate  and  phosphate.  The  salivary  calculi  may  vary  in  size  from  that  of 
a  small  grain  to  that  of  a  pea  or  still  larger  (a  salivary  calculus  has  been  found 
weighing  18.6  grms),  and  it  contains  a  variable  quantity  of  organic  sub- 
stances, 50-380  p.  m.,  which  remain  on  extracting  the  calculus  with  hydro- 
chloric acid.     The  chief  inorganic  constituent  is  calcium  carbonate. 


II.   The   Glands  of  the  Mucous  Membrane  of  the 
Stomach,  and  the  Gastric  Juice. 

Since  of  old,  the  glands  of  the  mucous  coat  of  the  stomach  have 
been  divided  into  two  distinct  kinds.  Those  which  occur  in  the 
greatest  abundance  and  which  have  the  greatest  size  in  the  fundus 
are  called  fundus  glands.,  also  renuin  or  i3ei:)sin  glands.  Those 
which  occur  only  in  the  neighborhood  of  the  pylorus  have  received 
the  name  of  pyloric  glands,  sometimes  also,  though  incorrectly, 
called  mucous  glands.  The  mucous  coating  of  the  stomach  is 
covered  throughout  with  a  layer  of  columnar  epithelium  which  is 
generally  considered  as  consisting  of  goblet  cells  that  produce  mucus 
by  a  metamorphosis  of  the  protoplasm. 

The  fundus  glands  contain  two  kinds  of  cells:  adelomoephic 
or  chief  cells,  and  delomorphic  or  parietal  cells,  the  latter 
formerly  called  rexxix  or  pepsin  cells.  Both  kinds  consist  of 
protoplasm  rich  in  proteids;  but  their  relationship  to  coloring 
matters  seems  to  show  that  the  albuminous  bodies  of  both  are  not 
identical.  The  nucleus  must  consist  chiefly  of  nuclein.  Besides 
the  above-mentioned  constituents  the  fundus  glands  contain  as  more 
specific  constituents  two  zymogens,  which  are  the  mother-substances 
of  the  pepsin  and  the  rennin,  besides  a  small  quantity  of  fat  and 
cholesterin. 

The  pyloric  glands  contain  cells  which  are  generally  considered 


202  DIGESTION. 

as  related  to  the  above-mentioned  chief  cells  of  the  fundas  glands. 
As  these  glands  were  formerly  thought  to  contain  a  larger  quantity 
of  mucin,  they  were  also  called  mucous  glands.  According  to- 
Heidexhain,  independent  of  the  columnar  epithelium  of  the 
excretory  ducts,  they  take  no  part  worthy  of  mention  in  the  forma- 
tion of  mucus,  which,  according  to  his  views,  is  effected  by  the 
epithelium  covering  the  mucous  membrane.  The  pyloric  glands 
also  seem  to  contain  the  zymogens  referred  to  above.  Alkali 
chlorides,  alkali  phosphates,  and  calcium  phosphates  are  found  in 
the  mucous  coating  of  the  stomach. 

Liebekmann'  has  obtained  an  acid-reacting  residue  on  digesting  tlie  mucosa 
of  the  stomach  with  pepsin  hydrochloric  acid,  which  strangely  contained  no 
nuclein,  but  only  a  proteid  containing  lecithin,  called  lecithalbumin.  To  this 
lecith albumin  he  ascribes  a  great  importance  in  the  secretion  of  hydrochloric 
acid  (see  below). 

The  Gastric  Juice.  The  observations  of  Helm'  and  Beau- 
mont "  on  persons  with  gastric  fistula  led  to  the  suggestion  that 
gastric  fistulas  be  made  on  animals,  and  this  operation  was  first  per- 
formed by  Bassotv  '  in  1842  on  a  dog.  Verneuil  ^  performed  the 
same  on  a  man  in  1876  with  successful  results.  These  fistulas  in 
animals  afford  an  excellent  means  of  studying  the  secretion  of 
gastric  juice  and  also  the  stomachic  digestion. 

In  a  fasting  condition  the  mucous  coat  is  often  nearly  dry; 
sometimes,  especially  in  certain  herbivora,  it  is  covered  with  a  layer 
of  viscid  so-called  mucus.  If  food  is  introduced  into  the  stomach, 
or  if  the  mucous  membrane  is  irritated  in  some  way,  then  a  secre- 
tion of  a  thin,  acid  fluid,  the  real  gastric  Juice,  takes  place.  The 
secretion  may  be  produced  by  mechanical  or  thermal  irritation 
(introduction  of  cold  water  or  pieces  of  ice  into  the  stomach),  or  by 
chemical  irritants.  Among  the  latter  we  include  alcohol  and  ether, 
which  when  in  too  great  concentration  do  not  produce  a  physio- 
logical secretion,  but  a  transudation  of  a  neutral  or  faintly  alkaline 
fluid  containing  albumin.     To  this  class  of  irritants  belong  carbon 

'  Pfliiger's  Arch.,  Bd.  50. 

'  Helm,  Zwei  Krankengeschichten.  Wien,  1803.  Cit.  from  Hermann's 
Handbuch,  Bd.  5,  Th.  2,  S.  39. 

8  "The  Physiology  of  Digestion,"  1833. 

*  Bull,  de  la  soc.  des  natur.  de  Moscou,  Tome  16.  Cited  from  Maly  in 
Hermann's  Handbuch,  Bd.  5,  S.  38. 

5  See  Ch.  Richet,  Du  sue  gastrique  chez  I'homme  et  les  animaus.  Paris, 
1878,  p.  158. 


GASTRIC  JUICE.  203 

dioxide  and  hydrochloric  acid;  the  last  especially  increases  the 
secretion  of  pepsin  (Jaworsky'),  spices,  meat  extracts,  neutral 
salts,  such  as  ISTaCl  (which  acts  like  alcohol  in  too  great  concentra- 
tion), and  alkali  carbonates.  The  alkali  carbonates  are  supposed 
by  certain  investigators  to  first  neutralize  the  acid  and  then  produce 
a  continuous  secretion  of  acid  gastric  Juice.  The  statements  in 
regard  to  the  action  of  different  bodies  on  the  secretion  of  gastric 
juice  are  still  rather  uncertain  and  often  contradictory. 

The  secretion  of  gastric  juice  is  reflexly  stimulated  from  the 
mouth.  After  the  introduction  of  water  into  the  stomach  a  rela- 
tively scanty  and  not  less  constant  flow  of  secretion  takes  place; 
while  on  the  contrary  if  digestible  food  is  introduced  a  more  abun- 
dant and  continuous  secretion  is  observed  (Schiff,"  Heidexhain^). 
But  in  these  cases  the  secretion  does  not  take  place  immediately, 
but  only  after  the  absorption  of  the  soluble  bodies  has  commenced. 
This  fact  justifies  the  usual  custom  of  commencing  a  meal  with 
fluid  nutritives,  such  as  soup.  The  beautiful  experiments  made  by 
Pawlow  and  Schoumow-Simaxowsky  *  have  shown  that  the 
secretion  of  gastric  juice  is  stimulated  reflexly  from  the  mouth,  and 
also  that  this  reflex  is  discontinued  on  cuttiug  through  the  vagi, 
and  that  the  secretion  in  the  stomachic  glands  is  caused  by  the 
central  nervous  system  through  special  secretory  nerve-fibres,  analo- 
gous to  the  secretion  of  saliva  and  pancreatic  juice. 

The  Qualitative  and  Quantitative  Composition  of  the  Gastric 
Jtiice.  The  gastric  juice,  which  can  hardly  be  obtained  pure  and 
free  from  residues  of  the  food  or  from  mucus  and  saliva,  is  a  clear, 
or  only  very  faintly  cloudy,  and  in  man  nearly  colorless  fluid  of  an 
insipid,  acid  taste  and  strong  acid  reaction.  It  contains,  as  form- 
elements,  glandular  cells  or  their  7iuclei,  mucus-corpuscles,  and  more 
or  less  changed  columnar  epitheliimi. 

The  acid  reaction  of  the  gastric  juice  depends  on  the  presence 
of  free  acid,  which,  as  we  have  learned  from  the  investigations  of 
C.  Schmidt,'  Eichet,'  and  others,  consists,  when  the  gastric  juice 
is  pure  and  free  from  particles  of  food,  chiefly  or  nearly  so  of  hydro- 

'  Deutscb.  med.  Wocliensclir.,  1887. 

'^  Le90us  sur  la  pliysiol.  de  la  digestion,  Tome  2,  1867. 

'Pfliiger's  Arch.,  Bd.  19. 

*  Du  Bois-Reymond's  Arch.,  1895. 

^  Bidder  and  Schmidt,  Die  Verdauungssafte,  etc.,  S.  44. 

«L.  c. 


264  DIGESTION. 

chloric  acid.  Coisttejean  '  has  regularly  found  traces  of  lactic  acid 
ill  the  pure  gastric  juice  of  fasting  dogs.  After  partaking  of  food, 
especially  after  a  meal  rich  in  carbohydrates,  lactic  acid  occurs 
abundantly,  and  sometimes  acetic  and  butyric  acids.  The  quantity 
of  free  hydrochloric  acid  in  the  gastric  juice  of  sheep  is  about  1.2 
p.  m.,  and  in  dogs,  according  to  the  ordinary  statements,  about  2-3 
p.  m.  ScHOUMOW-SiMA]srowsKT  °  has  observed  a  considerably 
higher  degree  of  acidity  in  perfectly  pure  and  fresh  gastric  juice  of 
a  dog,  namely,  4.6-5.8  p.  m.  Eiasantsew  '  states  that  the  gastric 
juice  of  the  cat  is  very  similar  to  that  of  the  dog  and  has  about  the 
same  degree  of  acidity,  4.11-5.84  p.  m.,  and  an  average  of  5.20 
p.  m.  EiCHET  *  found  as  average  for  80  determinations  of  human 
gastric  juice  1.7  p.  m.  free  hydrochloric  acid,  with  a  variation 
between  0.5  and  3  p,  m.  According  to  Szabo,^  Ewald,'  and 
others,  the  human  gastric  juice  contains  usually  about  2-3  p.  m. 
HCl.  E.ICHET  has  shown  that  the  acid  gastric  juice  acts  in  many 
respects  different  from  free  hydrochloric  acid  of  the  same  concen- 
tration, and  he  concludes  from  this  that  the  hydrochloric  acid  is  not 
iree,  but  combined  with  organic  substances  (leucin).  Contejean 
is  of  ^he  same  opinion,  and  has  found  that  gastric  juice  dissolves 
cobalt  hydrocarbonate  with  more  difficulty  and  slower  than  a 
hydrochloric  acid  of  the  same  concentration. 

Perfectly  fresh  gastric  j  nice  seems  to  contain  a  little  coagulable 
proteid,  but  contains  peptone  and  albumoses  on  standing  for  some 
time.  Among  the  organic  bodies  a  little  mucin  is  found  and  two 
enzymes,  pejjsifi  and  rennin,  especially  in  man.  The  sulphocyanic 
acid  found  by  Kellikg  '  in  the  contents  of  the  stomach  is  consid- 
ered by  Neistcki  and  Schoumow-Simakowsky  *  as  a  normal  con- 
stituent of  pure  saliva-free  gastric  juice  of  dogs. 

The  specific  gravity  of  gastric  juice  is  low,  1.001-1.010.  It  is 
therefore  corresponxLingly   poor   in   solids.      As  examples   of   the 

'  Contrilx  §,  I'etade  de  la  ptysiol.  de  restomac.  Thesis.  Paris,  1892.  Maly's 
Jahresber.,  Bd  32,  S.  293. 

«  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  33. 

3  Arch,  des  Sciences  biol.  de  St.  Petersbourg,  Tome  3. 

«  L.  c. 

'  Zeitschr.  f.  physiol.  Chem.,  Bd.  1. 

®  C.  A.  Ewald,  Klinik  der  Verdauungskrankheiten,  1890. 

">  Zeitschr.  f.  physiol  Chem.,  Bd.  18. 

*  Arch.  f.  exp.  Path.  u.  Pharm.,  Bi  34,  and  Ber.  d.  deutsch.  Chem.  Gesellsch., 
Bd.  28. 


PEPSIN. 


265 


composition  of  different  kinds  of  gastric  Juice  the  analyses  of 
C.  Schmidt  '  are  here  given.  It  must  be  remarked  that  the  human 
gastric  juice  analyzed  was  diluted  by  saliva  and  water  and  should 
therefore  not  be  considered  as  normal.  The  figures  are  parts  per 
1000. 


Water 

Solids 

Organic  substance 

NaCl 

CaCla 

KCl    

NH4CI .. 

Free  liydrocMoric  acid  (HCl). 

Ca3(P64), 

Mg3(P0,),    

FeP04 


Human   Gas- 
tric Juice 
mixed  with 
Saliva. 


994.40 
5.60 
3.19 
1.46 
0.06 
0.55 


0.20 
0.12 


Gastric  Gastric 

Juice  from   |  Juice  from 

Dog  free      Dog;  coiitaiu- 
from  Saliva,     ing  Saliva. 


973.0 
27.0 
17.1 
2.5 
0.6 
1.1 
0.5 
3.1 
1.7 
0.2 
0.1 


971.2 
28.8 
17.3 
3.1 
1.7 
1.1 
0.5 
2.8 
2.3 
0.3 
0.1 


Gastric 
Juice  of 
Sheep. 


986.15 
13.85 
4.05 
4.36 
0.11 
1.52 
0.47 
1.23 
1.18 
0.57 
0.33 


The  other  physiologically  important  constituents  of  gastric 
juice  are  pepsin  and  remmi. 

Pepsin.  This  enzyme  is  found,  with  the  exception  of  certain 
fishes,  in  all  vertebrates  thus  far  investigated. 

Pepsin  occurs  in  adults  and  in  new-born  infants.  This  condi- 
tion is  different  in  new-born  animals.  Wliile  in  a  few  herbivora, 
such  as  the  rabbit,  pepsin  occurs  in  the  mucous  coat  before  birth, 
this  enzyme  is  entirely  absent  at  the  birth  of  those  carnivora  which 
have  thus  far  been  examined,  such  as  the  dog  and  cat. 

In  various  invertebrates  a  ferment  has  also  been  found  which  has  a  prote- 
olytic action  in  acid  solutions.  It  has  been  shown  that  this  enzyme,  neverthe- 
less, is  not  in  all  animals  identical  with  ordinary  pepsin.  Darwin  hns  fur- 
ther found  that  certain  plants  which  feed  upon  insects  secrete  an  acid  juice 
which  dissolves  proteid,  but  it  is  still  doubtful  whether  these  plants  contain 
any  pepsin.  V.  Gorup-Besanez  '■'  has  isolated  from  vetch-seed  an  enzyme 
which  acts  like  pepsin,  but  whose  identity  with  pepsin  is  doubtful. 

Pepsin  is  as  difficult  to  isolate  in  a  pure  condition  as  other 
enzymes.'     The  purest  pepsin  was  that  prejoared  by  Beucke  and 

1  Cit.  from  v.  Gorup-Besanez,  Lehrbuch  d.  physiol.  Chem.,  4.  Aufl.,  S.  494. 

^  Ber.  d.  deutsch.  chem.  Gesellseh.,  Bdd.  7  and  8. 

'  Schoumow-Simanowsky,  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  33,  has  ob 
served  that  the  pure,  fresh  gastric  juice  of  a  dog  deposits  a  protein  substance 
containing  chlorine,  on  cooling,  and  this  he  considers  as  pure  pepsin.  This 
substance  is,  however,  precipitated  by  certain  proteid  reagents  which  even  do 


2G6  DIGESTION. 

Sundberg;  this  gave  negative  results  witli  most  reagents  for  pro- 
teids.  Pepsin,  therefore,  does  not  seem  to  be  a  true  albuminous 
substance.  It  is,  at  least  in  the  impure  condition,  soluble  in  water 
and  glycerin.  It  is  precipitated  by  alcohol,  but  only  slowly 
destroyed.  It  is  quickly  destroyed  by  heating  its  watery  solution 
to  boiling.  According  to  Biernacki  ^  pepsin  in  neutral  solutions 
is  destroyed  by  heating  to  +  55°  C.  In  the  presence  of  3  p.  m. 
HCl  a  temperature  of  55°  C.  is  without  action;  the  pepsin  is 
destroyed  by  heating  to  65°  C.  for  five  minutes.  On  adding 
peptone  and  certain  salts  the  pepsin  may  be  heated  to  70°  C.  with- 
out decomposing.  I]i  the  dry  state  it  can,  on  the  contrary,  be 
heated  to  over  100°  C.  without  losing  its  physiological  action.  The 
only  property  which  is  characteristic  of  pepsin  is  that  it  dissolves 
proteid  bodies  in  acid,  but  not  in  neutral  or  alkaline,  solntions  with 
the  formation  of  albumoses  and  peptones. 

The  methods  for  the  preparation  of  relatively  pure  pepsin 
depend,  as  a  rule,  upon  its  property  of  being  thrown  down  with 
finely  divided  j)recipitates  of  other  bodies,  such  as  calcium  phos- 
phate or  cholesterin.  The  rather  complicated  methods  of  Brucke^ 
and  Suistdberg'  are  based  upon  this  property.  A  relatively  pure 
pepsin  solution  intended  for  digestion  tests  and  of  effective  action 
may  be  prepared  by  the  followmg  metliod  as  suggested  by  Malt.* 
The  mucous  membrane  (of  the  pig's  stomach)  is  treated  with  water 
containing  phosphoric  acid,  and  the  filtrate  precipitated  by  lime- 
water;  the  precipitate,  which  contains  the  pepsin,  is  then  dissolved 
in  water  by  the  addition  of  hydrochloric  acid,  and  the  salts  removed 
by  dialysis,  by  which  means  the  pepsin  which  does  not  diffuse, 
remains  in  the  dialyzer.  A  pepsin  solution  somewhat  impure  but 
rich  in  pepsin,  and  which  can  be  kept  for  years,  may  be  obtained 
if,  as  suggested  by  v.  Wittichs/  we  extract  the  finely  divided 
mucous  membrane  with  glycerin,  or  better  with  glycerin  which 
contains  1  p.  m.  HCl.  To  each  part  by  weight  of  the  mucous  coat 
add  10-20  parts  glycerin.  This  is  filtered  after  8-14  days.  The 
pepsin  (together  with  much  albumin)  may  be  precipitated  by 
alcohol  from  this  extract.  If  this  extract  is  to  be  used  directly  for 
digestion  tests,  then  to  100  c.  c.  of  water  which  has  been  acidified 
with  1-4  p.  m.  HCl  add  2-3  c.  c.  of  the  extract. 

not  precipitate  very  powerful  commercial  pepsin,  and  therefore  it  cannot  be  a 
pure  enzyme. 

'  Zeitschr.  f.  Biologie,  Bd.  38. 

*  Wien.  Sitzungsber.,  Bd.  43. 

3  Zeitschr.  f.  physiol.  Chem.,  Bd.  9. 

<Pfluger's  Arch.,  Bd.  9. 

» Ibid.,  Bd.  3. 


ACTION  OF  PEPSIN.  267 

For  digestion  tests  an  infusion  of  the  mucous  membrane  of  the 
stomacli  may  be  used  directly  in  many  cases.  The  mucous  coat  is 
carefully  washed  with  water  (if  a  pig's  stomach  is  used)  and  finely 
cut;  if  a  calf's  stomach  is  employed,  only  the  outer  layer  of  the 
mucous  coat  is  scraped  off  with  a  watch-glass  or  the  back  of  a  knife. 
The  pieces  of  mucous  membrane  or  the  slimy  masses  obtained  by 
scraping  are  rubbed  with  pure  quartz-sand,  treated  with  acidified 
water,  and  allowed  to  stand  for  24  hours  in  a  cool  place  and  then 
filtered. 

In  the  preparation  of  artificial  gastric  juice  that  part  only  of  the 
mucous  coat  richest  in  pepsin  is  used ;  the  pyloric  part  is  of  little 
value.  A  strong,  impure  infusion  may  generally  be  obtained  from 
the  pig's  stomach,  while  a  relatively  pure  and  powerful  infusion  is 
obtained  from  the  stomach  of  birds  (hens).  The  stomachs  of  fish 
(pike)  also  yield  a  tolerably  pure  and  active  infusion.  An  active 
and  rather  pure  artificial  gastric  juice  may  be  prepared  by  scraping 
the  inner  layers  of  a  calf's  stomach  from  which  the  pyloric  end  has 
been  removed.  For  a  medium-sized  calf's  stomach  1000  c.  c.  of 
acidified  water  must  be  used. 

The  degree  of  acidity  required  in  the  infusion  depends  upon  the 
use  to  which  the  gastric  juice  is  to  be  put.  If  it  is  to  be  employed 
in  the  digestion  of  fibrin,  an  acidity  of  1  p.  m.  HCl  must  be 
selected,  while,  on  the  contrary,  if  it  is  to  be  used  for  the  digestion 
of  hard-boiled-egg  albumin,  an  acidity  of  2-3  p.  m.  HCl  is  prefer- 
able. This  last-mentioned  degree  of  acidity  is  generally  the  better, 
because  the  infusion  is  preserved  thereby,  and  at  all  events  it  is  so 
rich  in  pepsin  that  it  may  be  diluted  with  water  until  it  has  an 
acidity  of  1  p.  m.  HCl  without  losing  any  of  its  solvent  action  on 
unboiled  fibrin. 

The  preparation  of  acid  infusions  is  nowadays  unnecessary  on 
account  of  the  ability  of  getting  various  pepsin  preparations  in 
commerce  which  have  a  remarkable  activity.  Such  a  pepsin 
preparation  can  be  purified  when  necessary  by  following  the  method 
suggested  by  Kuhne.'  Precipitate  the  pepsin  together  with  the 
albumoses  by  ammonium  sulphate,  press  the  precipitate  and  dis- 
solve in  dilute  hydrochloric  acid,  and  let  it  undergo  auto-digestion. 
On  repeating  this  again  and  then  removing  the  salts  by  dialysis  we 
obtain  an  extraordinarily  active  pepsin,  but  which  is  still  less  pure 
than  when  obtained  by  the  metliods  of  Brucke  and  Sundberg. 

Tlw  Action  of  Pepsin  on  Proteids.  Pepsin  is  inactive  in  neutral 
or  alkaline  reactions,  but  in  acid  liquids  it  dissolves  coagulated 
albuminous  bodies.  The  proteid  always  swells  and  becomes  trans- 
parent before  it  dissolves.  Unboiled  fibrin  swells  up  in  a  solution 
containing  1  p.  m.  HCl,  forming  a  gelatinous  mass,  and  does  not 
dissolve  at  ordinary  temperature  within  a  couple  of  days.  Upon 
'  Zeitsclir.  f.  Biologie,  Bd.  32,  S.  428. 


268  DIGESTION. 

the  addition  of  a  little  pepsin,  however,  this  swollen  mass  dissolves 
quickly  at  an  ordinary  temperature.  Hard-boiled-egg  albumin,  cut 
in  thin  pieces  with  sharp  edges,  is  not  perceptibly  changed  by  dilute 
acid  (2-4  p.  m.  HCl)  at  the  temperature  of  the  body  in  the  course 
of  several  hours.  But  the  simultaneous  presence  of  pepsin  causes 
the  edges  to  become  clear  and  transparent,  blunt  and  swollen,  and 
the  albumin  gradually  dissolves. 

From  what  has  been  said  above  in  regard  to  pepsin,  it  follows 
that  proteids  may  be  employed  as  a  means  of  detecting  pepsin  in 
liquids.  Fibrin  may  be  emj)loyed  as  well  as  hard-boiled-egg  albu- 
min, which  latter  is  used  in  the  form  of  slices  with  sharp  edges. 
As  the  fibrin  is  easily  digested  at  the  normal  temperature,  while 
the  jDepsin  test  with  egg-albumin  requires  the  temperature  of  the 
body,  and  as  the  test  with  fibrin  is  somewhat  more  delicate,  it  is 
often  preferred  to  that  with  egg-albumin.  When  we  speak  of  the 
^'pejjsin  ^es^ "  without  further  explanation,  we  ordinarily  under- 
stand it  as  the  test  with  fibrin. 

This  test  nevertheless  requires  care.  The  fibrin  used  should  be 
ox  fibrin  and  not  pig  fibrin,  which  last  is  dissolved  too  readily  with 
dilute  acid  alone.  The  unboiled  fibrin  may  be  dissolved  by  acid 
alone  without  pepsin,  but  this  generally  requires  more  time.  In 
testing  with  unboiled  fibrin  at  normal  temperature,  it  is  advisable 
to  make  a  control  test  with  anothei*  portion  of  the  same  fibrin  with 
acid  alone.  Since  at  the  temperature  of  the  body  unboiled  fibrin  is 
easier  dissolved  by  acid  alone,  it  is  best  always  to  work  with  boiled 
fibrin. 

As  pepsin  has  not,  thus  far,  been  prepared  in  a  positively  pure 
condition,  it  is  impossible  to  determine  the  absolute  quantity  of 
pepsin  in  a  liquid.  It  is  only  possible  to  compare  the  relative 
amounts  of  pepsin  in  two  or  more  liquids,  which  may  be  done  in 
several  ways.  As  the  best  of  these  we  give  the  following  method 
as  suggest  by  Brucke. 

If  two  pepsin  solutions  A  and  B  are  to  be  compared  with  eacli  other  rela- 
tively to  the  amounts  of  pepsin  they  contain,  they  must  first  be  brought  to  the 
proper  degree  of  acidity,  about  1  p.  m.  HCl,  care  being  taken  that  one  is  not 
more  diluted  than  the  other.  Then  prepare  a  large  number  of  specimens  of 
each  solution  by  diluting  with  hydrochloric  acid  of  1  p.  m.  HCl,  so  that  they 
contain  respectively  |,  ^,  |,  y\,  3^^,  and  so  on,  the  amount  of  pepsin  in  the 
original  liquid  being  1.  If  the  original  quantity  of  pepsin  in  the  two  liquids 
is  designated  by  p  and  p',  we  then  have  the  two  series  of  liquids  : 

A  B 

Ip  Ip' 

IP  iP' 

iP  ip' 

TSP  hP, 

i^P  -hP 


ACTION  OF  PEPSIN.  2r.9 

Tlien  a  small  piece  of  boiled-egg  albumin,  obtained  by  cutting  thin  sliieh- 
■with  a  cork-cutter,  is  placed  in  each  test,  or  a  small  tiake  ol'  fibrin  is  added. 
Of  course  care  must  be  taken  to  add  the  same-sized  slice  of  egg-albumin  or 
tiake  of  fibrin.  Now  observe  and  note  exactly  the  time  when  each  test  of  the 
two  emeries  begins  to  digest  and  when  it  ends,  and  it  will  be  found  that  certain 
tests  of  one  series  make  about  the  same  progress  as  certain  tests  of  the  otlier 
series.  It  may  be  inferred  from  this  that  they  contain  about  the  same  quan- 
tity of  pepsin.  As  example,  it  is  found  in  one  series  of  tests  that  the  digestive 
rapidity  of  the  tests  p  \,  p  j^^,  p  ^V  is  about  the  same  as  the  tests  p'  |,  p'  \,  p'  \  ; 
therefore  we  conclude  that  the  liquid  A  is  about  four  times  as  rich  in  pepsin 
as  the  liquid  B. 

Another  method  as  suggested  by  Mette'  gives  more  exact  results  according 
to  the  investigations  of  Samoji.OPF.  ^  Draw  up  liquid  white  of  &^^  in  a  glass 
tube  of  about  1  to  2  mm.  diameter  and  coagulate  the  albumin  in  the  tube  by 
heating,  cut  the  ends  of  the  tube  ofE  sharply,  add  two  tubes  to  each  test-tube 
with  a  few  cc.  of  acid  pepsin  solution,  allow  to  digest  at  the  bodily  tempera- 
ture, and  after  a  certain  time  measure  the  lineal  extent  of  the  digested  layer  of 
albumin  in  the  various  tests.  From  the  rapidity  of  digestion  expressed  from 
the  extent  of  the  digested  layer,  we  can  calculate  the  relative  quantity  of 
pepsin,  according  to  the  rule  first  found  by  SchIitz,^  that  the  energy  of  diges- 
tion of  different  pepsin  solutions  is  the  square  root  of  the  quantity  of  pepsin  it 
contains.  This  rule,  however,  only  applies  to  sufficiently  dilute  pepsin  solu- 
tions. 

The  rapidity  of  the  pepsin  digestion  depends  on  several  circum- 
stances. Thus  different  acids  are  unequal  in  their  action ;  hydro- 
chloric acid  shows  a  more  powerful  action  than  any  other,  whether 
an  organic  or  an  inorganic  acid.  The  degree  of  acidity  is  also  of 
the  greatest  importance.  With  hydrochloric  acid  the  degree  of 
acidity  is  not  the  same  for  different  proteid  bodies.  For  fibrin  it  is 
0.8-1  p.  m.,  for  myosin,  casein,  and  vegetable  albumin  about  1  p.  m., 
for  hard-boiled-egg  albumin,  on  the  contrary,  about  2.5  p.  m. 
The  rapidity  of  the  digestion  increases,  at  least  to  a  certain  point, 
with  the  quantity  of  pepsin  present,  unless  the  pepsin  added  is 
contaminated  by  a  large  quantity  of  products  of  digestion,  which 
may  prevent  its  action.  The  accumulation  of  products  of  digestion 
has  a  retarding  action  on  digestion,  although,  according  to  Chit- 
tenden and  Amermak,^  the  removal  of  the  digestion  products  by 
means  of  dialysis  does  not  essentially  change  the  relationship  be- 
tween the  albumoses  and  true  peptones.  Pepsin  acts  slower  at  low 
temperatures  than  it  does  at  higher.  It  is  even  active  in  the 
neighborhood  of  0°C.,  but  digestion  takes  place  very  slowly  at  this 
temperature.  With  increasing  temperature  the  rapidity  of  diges- 
tion also  increases  until  about  40°  C,  when  the  maximum  is  reached. 

'  Cited  from  Samojloff.     See  foot-note  2. 

**  Arch,  des  Sciences  biol.  de  St.  Petersbourg,  Tome  2,  8.  699. 

3  Zeitschr.  f.  physiol.  Chem.,  Bd.  9,  S.  577. 

*  Journal  of  Physiol.,  1893. 


270  DIGESTION. 

According  to  the  investigations  of  Flaum^  it  is  probable  that  the 
relationship  between  albumoses  and  peptones  remains  the  same, 
irrespective  of  whether  the  digestion  took  place  at  a  low  or  high 
temperature  as  long  as  the  digestion  is  continuous  for  some  time. 
If  the  sivelU7ig  up  of  the  proteid  is  jorevented,  as  by  the  addition  of 
neutral  salts,  such  a?  NaCl  in  sufficient  amounts,  or  by  the  addition 
of  bile  to  the  acid  liquid,  digestion  can  be  prevented  to  a  greater  or 
less  extent.  Foreign  hodies  of  different  kinds  produce  different  ac- 
tions, in  which  naturally  the  variable  quantities  in  which  they  are 
added  are  of  the  greatest  importance.  Salicylic  acid  and  carbolic 
acid  hinder  the  digestion,  while  arsenious  acid  promotes  it  (Chit- 
tenden), and  hydrocyanic  acid  is  relatively  indifferent.  Alcohol 
in  large  quantities  {10 fo  and  above)  disturbs  the  digestion,  while 
small  quantities  act  indifferently.  Metallic  salts  in  very  small  quan- 
tities may  indeed  sometimes  accelerate  digestion,  but  otherwise  they 
tend  to  retard  it.  The  action  of  metallic  salts  in  different  cases  can 
be  explained  in  different  ways,  but  they  often  seem  to  form  with 
proteids  insoluble  or  difficultly-soluble  combinations.  The  alkaloids 
may  also  retard  the  pepsin  digestion  (Chittenden  and  Allen).'' 
A  very  large  number  of  observations  have  been  made  in  regard  to 
the  action  of  foreign  substances  on  artificial  pepsin  digestion,  but 
as  these  observations  have  not  given  any  direct  result  in  regard  to 
the  action  of  these  same  substances  on  natural  digestion,  we  will 
not  here  further  discuss  them. 

The  Products  of  the  Digestion  of  Proteids  dy  Means  of  Pepsin 
and  Acid.  In  the  digestion  of  nucleoproteids  or  nucleo-albumins 
an  insoluble  residue  of  nuclein  or  pseudo-nuclein  always  remains. 
With  experiments  on  casesin  Salkowski^  has  shown  that  the  para- 
nuclein  first  split  off  Avhich  contains  according  to  Willdenow,^ 
phosphorus  in  organic  combination,  may  be  dissolved  by  continuous 
digestion.  Some  orthophosphoric  acid  is  hereby  split  off,  but  an 
organic  phosphorized  acid  is  also  formed. 

Fibrin  also  yields  an  insoluble  residue,  which  consists,  at  least 
in  great  part,  of  nuclein,  derived  from  the  form-elements  enclosed 

'  Zeitschr.  f.  Biologie,  Bd.  28. 

'•*  Yale  College  Studies,  Vol.  1,  p.  76.  See  also  Chittenden  and  Stewart, 
McL.,  Vol.  3,  p.  60. 

'  Centralbl.  f.  d.  med.  Wissensch.,  1893,  S.  385  and  467.  See  also  Sontag, 
ibid.,  S.  419,  and  Moraczewski,  Zeitschr.  f.  physiol.  Chem.,  Bd.  20. 

^  "  Zur  Kenntniss  der  peptischen  Verdauung  des  Kaseins."  Inaug.  Diss. 
Bern.,  1893. 


PRODUCTS  OF  THE  ACTION  OF  PEPSIN.  271 

in  the  blood-clot.  This  residue  which  remains  in  the  digestion  of 
certain  albuminous  bodies  is  called  dyspei^tone  by  Meissner.'  If 
the  solution  is  filtered  after  a  finished  digestion  and  neutralized,  it 
gives  in  different  cases  a  more  or  less  abundant  precipitate  of  acid 
albuminate,  or  a  mixture  of  albuminates  called  parapeptone  by 
Meissxer.  After  filtering  this  precipitate  and  concentrating  the 
filtrate  again,  some  proteid  often  separates  in  the  warmth.  If  this 
23recipitate  be  filtered,  the  filtrate  now  contains  alhumoses  and  pep- 
tones in  the  ordinary  sense,  while  the  so-called  true  peptone  of 
Kuhne  ma}'^  sometimes  be  entirely  absent,  and  in  general  is 
■obtained  in  quantity  worth  mentioning  only  after  a  more  continu- 
ous and  intensive  digestion.  The  relationship  between  the  albu- 
moses  and  peptones  in  the  ordinary  sense  changes  very  much  in 
different  cases  and  in  the  digestion  of  various  albuminous  bodies. 
For  instance,  a  larger  quantity  of  primary  albumoses  is  obtained 
from  fibrin  than  from  hard-boiled  egg  albumin  or  from  the  pro- 
teids  of  meat.  In  the  digestion  of  unboiled  fibrin  an  intermediate 
product  may  be  obtained  in  the  earlier  stages  of  the  digestion — 
a  globulin  which  coagulates  at  +  55°  C.  (Hasebroek^).  For 
information  in  regard  to  the  different  albumoses  and  peptones 
which  are  formed  in  pepsin  digestion,  the  reader  is  referred  to  pre- 
vious pages  (33-39). 

Action  of  Pepsin  Hydrochloric  Acid  on  other  Bodies.  The  gela- 
tin-forming substance  of  the  connective  tissue,  of  the  cartilage  and 
of  the  bones,  from  which  last  the  acid  only  dissolves  the  inorganic 
substances,  is  converted  into  gelatin  by  digesting  with  gastric 
juice.  The  gelatin  is  further  changed  so  that  it  loses  its  property 
of  gelatinizing  and  is  converted  into  a  so-called  gelatin  pei)tone 
(see  page  55).  True  mucin  (from  the  submaxillary)  is  dissolved 
by  the  gastric  juice  and  yields  a  substance  similar  to  peptone  and  a 
reducing  substance  similar  to  that  obtained  by  boiling  with  a 
mineral  acid.  Elastin  is  dissolved  more  slowly  and  yields  the 
above-mentioned  substances  (page  52).  Keratin  and  the  epidermis 
formation  are  insoluble.  Nnclein  is  not  dissolved  and  the  cell- 
nuclei  are  therefore  insoluble  in  gastric  juice.  The  animal  cell- 
membrane  is,  as  a  rule,  more  easily  dissolved  the  nearer  it  stands  to 
elastin,  and  it  dissolves  with  greater  difficulty  the  more  closely  it  is 

'  The  works  of  Meissner  on  pepsin  digestion  are  found  in  Zeitschr.  f.  rat. 
Med.,  Bdd.  7,  8,  10, 12,  and  14. 

'  Zeitschr.  f.  physiol.  Chem.,  Bd.  11. 


272  DIGESTION. 

related  to  keratin.  The  memhrane  of  the  plant-cell  is  not  dissolved. 
Oxylicemogloblin  is  changed  into  hsematin  and  acid  albuminate, 
the  latter  undergoing  further  digestion.  It  is  for  this  reason  that 
blood  is  changed  into  a  dark-brown  mass  in  the  stomach.  The 
gastric  juice  does  not  act  on  fat,  but,  on  the  contrary,  on  fatty 
tissue,  dissolving  the  cell-membrane,  setting  the  fat  free.  Gastric 
juice  has  no  action  on  starch  or  the  simple  varieties  of  sugar.  The 
statements  in  regard  to  the  ability  of  gastric  juice  to  invert  cane- 
sugar  are  very  contradictory.  At  least,  this  action  of  the  gastric 
juice  is  not  constant,  and,  according  to  Voit,  '  if  it  is  present  at  all, 
it  is  probably  due  to  the  action  of  the  acid. 

Pepsin  alone,  as  above  stated,  has  no  action  on'proteids,  and  an 
acid  of  the  intensity  of  the  gastric  juice  can  only  very  slowly,  if  at 
all,  dissolve  coagulated  albumin  at  the  temperature  of  the  body. 
Pepsin  and  acid  together  not  only  act  more  quickly,  but  qualita- 
tively they  act  otherwise  than  the  acid  alone.  If  liquid  proteid  is 
digested  with  hydrochloric  acid  of  2  p.  m.,  it  is  conyerted  into  acid 
albuminates  ;  but  if  pepsin  is  previously  added  to  the  acid,  the 
formation  of  syntonin  takes  place  essentially  slower  under  the  same 
conditions  (Meissnee).  From  this  it  is  inferred  that  a  part  of 
the  hydrochloric  acid  is  combined  with  the  pepsin,  and  we  have 
here  a  proof  of  the  existence  of  a  paired  acid,  called  by  C.  Schmidt 
pepsin  hydrochloric  acid. 

It  has  been  further  suggested  that  this  hypothetical  acid  is  possibly  decom- 
posed in  digestion  into  free  pepsin  and  free  hydrochloric  acid,  which  in  statu 
naseendi  dissolves  proteids  to  a  certain  degree.  The  pepsin  set  free  reunites 
with  a  new  portion  of  acid,  forming  pepsin  hydrochloric  acid,  and  in  contact 
with  proteids  is  further  decomposed  as  above  described.  It  is  hardly  necessary 
to  mention  that  this  statement  is  only  an  unproved  hypothesis. 

Rennin  or  chymosijst  is  the  second  enzyme  of  the  gastric  juice. 
It  occurs  in  human  gastric  under  physiological  conditions,  but  may 
be  absent  under  special  pathological  conditions,  such  as  carcinoma, 
atrophy  of  the  mucous  membrane,  and  certain  chronic  catarrhs 
(Boas,  JoHNSOisr,  Klbmperer).^  It  is  habitually  found  in  the 
neutral,  watery  infusion  of  the  fourth  stomach  of  the  calf  and 
sheep,  es|)ecially  in  an  infusion  of  the  fundus  part.  In  other 
mammals  and  in  birds  it  is  seldom  found,  and  in  fishes  hardly  ever 
in  the  neutral  infusion. 

1  Zeitschr.  f.  Biologie,  Bd.  28,    also  contains  the  literature. 

2  A  good  review  of  the  literature  may  be  found  in  Szydlowski,  Beitrag  zur 
Kenntniss  des  Labenzym  nach  Beobachtungen  an  Saugluigen,  Jahrb.  f.  Kin- 
derheilkunde,  N.  F.,  Bd.  34. 


EENNIK  273 

In  these  cases  a  rennin-forming  substance,  a  rennin  zymogen^ 
occurs  which  is  converted  into  rennin  by  the  action  of  an  acid. 

Rennin  is  just  as  difficult  to  prepare  in  a  pure  state  as  the 
other  enzymes.  The  purest  rennin  enzyme  thus  far  obtained  did 
not  give  the  ordinary  proteid  reactions.  On  heating  its  sohitions 
it  is  destroyed,  and  indeed  more  easily  in  acid  tlian  in  neutral 
solutions.  If  an  active  and  strong  infusion  of  a  mucous  coat  in 
water  containing  3  p.  m.  IK'l  is  heated  to  37-40°  C.  for  48  hours, 
the  rennin  is  destroyed,  while  the  pepsin  remains.  A  pepsin  solu- 
tion free  from  rennin  can  be  obtained  in  this  way.  Rennin  is 
characterized  by  its  jjliysiological  action,  which  consists  in  coagu- 
lating milk  or  a  casein  solution  containing  lime,  if  neutral  or  very 
faintly  alkaline. 

Rennin  may  be  carried  down  by  other  precipitates  like  other 
enzymes,  and  thus  may  be  obtained  relatively  pure.  It  may  also 
be  obtained,  contaminated  with  a  great  deal  of  proteids,  by  extract- 
ing the  mucous  coat  of  the  stomach  with  glycerin. 

A  comparatively  piire  solution  of  rennin  may  be  obtained  in  the 
following  way.  An  infusion  of  the  mucous  coat  of  the  stomacli  in 
hydrochloric  acid  is  prepared  and  then  neutralized,  after  which  it 
is  repeatedly  shaken  with  new  quantities  of  magnesium  carbonate 
until  the  i:)epsin  is  precipitated.  The  filtrate,  which  should  act 
strongly  on  milk,  is  precipitated  by  basic  lead  acetate,  the  precipi- 
tate decomposed  with  very  dilute  sulphuric  acid,  the  acid  liquid 
filtered  and  treated  with  a  solution  of  stearin  soap.  The  rennin  is: 
carried  down  by  the  fatty  acids  set  free,  and  when  these  last  are 
placed  in  water  and  removed  by  shaking  with  ether,  the  rennin 
remains  in  the  watery  solution. 

A  fasting  animal  may  secrete  a  strongly-acid  gastric  juice. 
The  acid  of  tlie  gastric  juice  then  cannot  be  derived  from  the  foods^ 
but  must  originate  in  the  mucous  coat.  As  the  pyloric  glands, 
which  contain  no  parietal  cells,  secrete  an  alkaline  secretion 
according  to  HEiDE]srHAi]sr '  and  Klemeistsiewicz,"  while  the 
fundus  glands,  wliich  contain  these  cells,  yield  an  acid  secretion, 
it  is  generally  assumed  with  Heidenhain"  that  the  parietal  cells 
are  of  special  importance  in  the  secreticn  of  free  hydrochloric  acid 
— a  statement  which  other  observations  tend  to  confirm.  The 
later    investigations    of    Frankel'    and    Contejean  *    seem    to 

'  Pflilger's  Arch.,  Bdd.  18  and  19.  See  also  Hermann's  Handbuch,  Bd.  5, 
Tb.  1,  "  Absonderungsvorgange.'' 

'  Wien.  Sitzungsber,  Bd.  71. 

5  Pfluger's  Arch.,  Bdd.  48  and  50. 

■*  Contribution  k  I'etude  de  la  pbysiol.  de  I'estomac,  Thfese,  Paris,  1892.  Also 
Maly's  Jahresber.,  Bd.  33,  S.  393. 


274:  DIGESTION. 

contradict  this  statement.  They  claim  that  the  chief  cells  as  well 
as  the  parietal  cells  take  part  in  the  formation  of  acid. 

That  the  hydrochloric  acid  must  originate  from  the  chlorides  of 
the  blood  is  evident,  and  Kahist  '  has  given  a  direct  proof  for  this. 
He  found  in  dogs  that  after  a  suflBciently  long  common-salt  starva- 
tion that  the  stomach  secreted  a  gastric  juice  containing  pepsin  but 
no  free  hydrochloric  acid.  On  the  administration  of  soluble  chlo- 
rides a  gastric  juice  containing  hydrochloric  acid  was  immediately 
secreted.  We  do  not  know  how  the  secretion  of  free  hydrochloric 
acid  originates. 

Whereas  it  used  to  be  considered  that  the  chlorides  were 
decomposed  by  an  electrolysis  or  by  organic  acids  produced  in  the 
mucosa,  we  now  rather  generally  accept  the  process  as  suggested 
by  Maly. 

Malt  °  has  called  attention  to  the  fact  that,  on  account  of  the 

presence  of  a  large  quantity  of  free  carbon  dioxide  in  the  blood  and 

the  avidity  of  the  same,  there  must  be  present  among  the  numerous 

combinations  of  acids  and  bases  which  exist  in  the  serum  traces  of 

free  hydrochloric  acid  in  addition  to  acid  salts.     As  these  traces  of 

hydrochloric  acid  are  removed  from  the  blood  by  means  of  rapid 

diffusion  by  the  glands,   the  mass-action  of   the  carbon  dioxide 

must  set  free  new  traces  of  hydrochloric  acid  in  the  blood.     In 

this  way  may  be  explained  the  secretion  in  the  blood  of  large 

quantities  of  hydrochloric  acid  from  the  chlorides,  but  the  proof 

that  the  hydrochloric  acid  set  free  passes  into  the  gastric  juice 

simply  by  diffusion,  is  missing.     Similar  processes  in  other  animal 

glands  render  it  probable  that  here,  as  in  other  cases  of  secretion, 

we  have  to  deal  with  a  yet  unexplained  specific  secretory  action  of 

the  glandular  cells. 

L  Liebermann^  has  lately  proposed  a  new  theory  for  the  secretion  of  hydro- 
chloric acid.  According  to  him  lecithalbumin  occurs  in  the  glandular  cells,  and 
this  combines  readily  with  alkalies.  The  more  acti%'e  metabolism  in  the  glands 
during  work  leads  to  an  abundant  formation  of  carbon  dioxide,  and  this  carbon 
dioxide  by  its  mass-action  sets  hydrochloric  acid  free  from  the  chlorides.  The 
hydrochloric  acid  passes  into  the  secretion  hj  dilfusion,  while  the  alkalies  com- 
bine with  the  lecithalbumin.  In  regard  to  details  of  this  theory  we  must  refer 
the  reader  to  the  original  article. 

Nen"Cki  and    Schoumow-Siman'Owskt  *   have   confirmed,    on 

dogs,  theo  bservations  of  Kulz/  namely,  that  the  introduction  of 

>  Zeitschr.  f.  physiol.  Chem.,  Bd.  10. 

^  Ibid.,  1. 

3  Pfluger's  Arch.,  Bd.  50. 

^  Arch,  des  Sciences  biol.  de  St.  Petersboug,  Tome  3. 

<>  Zeitschr.  f.  Biologie,  Bd.  23. 


PROPEPSIN.  27  5 

alkali  bromides  or  iodides  causes  a  replacement  of  the  hydrochoric 
acid  of  the  gastric  juice  by  HBr  or  to  a  smaller  extent  by  HI. 
On  the  determination  of  the  quantity  of  chlorine  in  the  various 
tissues  and  fluids  under  normal  conditions  and  after  the  adminis- 
tration of  XaBr  they  have  shown  that  bromine  can  also  replace  the 
chlorine  in  the  organism. 

After  an  abundant  meal,  when  tlie  store  of  pepsin  in  the  stom- 
ach is  completely  exhausted,  Schiff  claims  that  certain  bodies, 
especially  dextrin,  have  the  property  of  causing  a  supply  of  pepsin 
in  the  mucous  membrane.  This  '"'charge  theory,"  though  experi- 
mentally proved  by  several  investigators,  has  nevertheless  not  yet 
been  confirmed.  On  the  contrary,  the  statement  of  Schiff'  that  a 
substance  forming  pepsin,  a  ''pepsinogen'"'  or  ^' propepsin^'  occurs 
in  the  ventricle  has  been  proved.  Laxgley'  has  shown  positively 
the  existence  of  such  a  substance  in  the  mucous  coat.  This  sub- 
stance, propepsin,  shows  a  comparatively  strong  resistance  to  dilute 
alkalies  (a  soda  solution  of  5  p.  m.),  which  easily  destroy  pepsin 
(Laxglet).  Pepsin,  on  the  other  hand,  withstands  better  than 
propepsin  the  action  of  carbon  dioxide,  which  quickly  destroys  the 
latter.  The  occurrence  of  a  rennin  zymogen  in  the  mucous  coat 
has  been  mentioned  above. 

The  question  in  which  cells  the  two  zymogens,  especially  the 
propepsin,  are  produced  has  been  extensively  discussed  for  several 
years.  Formerly  it  was  the  general  opinion  that  the  parietal  cells 
were  pepsin  cells,  but  since  the  investigations  of  Heidexhain  and 
Ms  pupils,  Langlet  and  others,  the  formation  of  pepsin  has  been 
shifted  to  the  chief  cells.  Fkaxkel  and  Coxtejean  have  lately 
presented  objections  to  the  views  of  Heidexhaix  that  certains  cells 
produce  the  zymogens  and  others  only  the  acid. 

The  Pyloric  Secretion.  That  part  of  the  pyloric  end  of  the 
dog's  stomach  which  contains  no  fundus  glands  was  dissected  by 
Klemexsiewicz,  one  end  being  sewed  together  in  the  shape  of  a 
blind  sack  and  the  other  sewed  into  the  stomach.  From  the 
fistula  thus  created  he  was  able  to  obtain  the  pyloric  secretion  of  a 
living  animal.  This  secretion  is  alkaline,  viscous,  jelly-like,  rich 
in  mucin,  of  a  specific  gravity  of  1.009-1.010,  and  containing 
16.5-20.5  p.  m.  solids.  It  has  no  effect  on  fat,  but  acts,  though 
very  slowly,  on  starch,    converting   it    into    sugar,    and   contains 

'  Lemons  sur  la  physiol.  de  la  digestion,  1867,  Tome  2. 
'  Langlev  and  Edkins,  Journ.  of  Physiol. ,  Vol.  7. 


276  DIGESTION. 

ordinarily  j)epsin,  which  sometimes  occurs  in  considerable  amounts. 
This  has  been  observed  by  HEiDEifHAiN'  in  permanent  pyloric 
fistula.  CoNTEJEAN^  has  investigated  the  pyloric  secretion  in 
other  ways,  and  finds  that  it  contains  both  acid  and  pepsin.  The 
alkaline  reaction  of  the  secretions  investigated  by  HEiDEisTHAiisr  and 
Klemensiewicz  is  due,  according  to  Co]srTEJEA]Sf,  to  an  abnor- 
mal secretion  caused  by  the  operation,  because  the  stomach  readily 
yields  an  alkaline  juice  instead  of  an  acid  one  under  abnormal 
conditions.  Akermajst'''  has  found,  in  accordance  with  Heiden"- 
HAiisr  and  Klemen'Siewicz,  that  the  pyloric  secretion  of  a  dog  was 
alkaline.  He  could  never  detect  free  acid,  but  always  pepsin  and 
rennin. 

The  secretion  of  the  juice  of  the  stomach  is  dependent  to  a 
great  extent  upon  the  excitement  acting  on  the  mucous  coat  of  the 
stomach,  and  it  follows  from  this  that  the  quantity  of  secretion 
under  different  conditions  must  vary  considerably.  The  statements 
of  the  quantity  of  gastric  juice  secreted  in  a  certain  time  are  there- 
fore so  unreliable  that  they  need  not  be  taken  into  account. 

The  Chyme  and  the  Digestion  in  the  Stomach.  By  means  of 
the  mechanical  irritation  of  the  mucous  coat  of  the  stomach,  as 
well  as  by  the  chemical  irritation  caused  by  the  food  and  saliva,  an 
abundant  secretion  of  gastric  juice  occurs.  The  food  is  thereby 
freely  mixed  with  liquid  and  is  gradually  converted  into  a  pulpy 
mass,  called  the  chyme.  This  mass  is  acid  in  reaction,  and,  with 
the  exception  of  the  interior  of  large  pieces  of  meat  or  other  solid 
foods,  the  chyme  is  acid  throughout.  The  transformation  products 
of  the  digestion  of  proteids  and  carbohydrates  can  be  detected  in 
the  chyme;  likewise  more  or  less  changed  undigested  residues  of 
swallowed  food,  which  indeed  form  the  chief  mass  of  the  chyme. 

In  the  chyme  morsels  of  meat  more  or  less  changed  are  found 
which,  when  unboiled  meat  is  partaken  of,  may  be  much  swollen 
and  slippery.  Muscle  and  cartilage  are  also  often  swollen  and 
slippery,  while  pieces  of  bone  sometimes  show  a  rough  and  uneven 
surface  after  the  digestion  has  continued  for  some  time,  which  de- 
pends upon  the  fact  that  the  gelatinous  substances  of  the  bone  are 
attacked  more  quickly  by  the  gastric  juice  than  the  earthy  parts. 
Milk  coagulates  in  the  stomach  by  the  combined  action  of  the  ren- 
nin and  the  acid,  but  in  certain  cases  by  the  action  of  the  acid 

'  L.  c. 

2  Skand.  Arch.  f.  Physiol.,  Bd.  5. 


DIGESTION  IN  THE  STOMACH.  277 

alone.  From  the  relative  quantities  of  tlie  swallowed  milk  to  the 
other  food  either  large  and  solid  lumps  of  cheese  are  formed  or 
smaller  lumps  or  grains  which  are  divided  in  the  pulpy  mass. 
Cow's  milk  regularly  yields  large,  solid  masses  or  lumps;  Luman 
milk  gives,  on  the  contrary,  a  fine,  loose  coagulum  or  a  fine  precip- 
itate which  is  immediately  dissolved  in  part  by  the  acid  liquid.  The 
milk-sugar  may  pass  into  lactic-acid  fermentation,  and  this,  accord- 
ing to  RiCHET,  is  the  reason  why  the  acid  reaction  of  the  contents 
of  the  stomach  is  greater  at  the  end  of  the  digestion  of  a  meal  con- 
sisting mainly  of  milk. 

Bread,  especially  when  not  too  fresh,  is  converted  rather  easily 
into  a  pulpy  mass  in  the  stomach.  Other  vegetable  foods,  such  as 
POTATOES,  may,  if  not  sufficiently  masticated,  often  be  found  in  the 
contents  of  the  stomach,  very  little  changed,  several  hours  after  a 
meal. 

Starch  is  not  converted  into  sugar  by  the  gastric  juice,  but  in 
the  first  phases  of  the  digestion,  before  a  large  quantity  of  hydro- 
chloric acid  has  accumulated,  it  seems  that  the  action  of  the  saliva 
continues,  and  therefore  the  presence  of  dextrin  and  sugar  can  be 
detected  in  the  contents  of  the  stomach.  Besides  this  the  carbohy- 
drates in  the  stomach  may  in  part  undergo  a  lactic-acid  fermenta- 
tion, caused  by  the  micro-organisms  present. 

According  to  the  investigations  of  Ellenberger  and  Hoff- 
meister'  on  horses  and  pigs,  after  a  meal  rich  in  amylaceous  bodies 
in  the  first  phase  of  the  digestion,  an  amtioltsis  takes  place  with 
the  formation  of  lactic  acid;  then  gastric  juice  containing  hydro- 
chloric acid  is  secreted,  when  a  second  phase  in  which  proteolysis 
takes  place.  As  a  rule,  the  formation  of  lactic  acid  decreases  as  the 
secretion  of  hydrochloric  acid  increases.  Ewald  and  Boas^  claim 
that  a  similar  condition  also  exists  in  human  beings.  They  claim 
that  there  is  in  the  first  stage  of  digestion  a  predominance  of  lactic 
acid  in  the  stomach,  in  the  second  a  simultaneous  occurrence  of 
lactic  and  hydrochloric  acids,  and  in  the  third  stage  almost  exclu- 
sively hydrochloric  acids.  Kjaergaard  ^  has  lately  formed  the 
same  conclusions  from  his  investigations  on  children  and  robust 
persons.     In  nersons  with  altered  blood-vessels  due  to  senility  the 

■  Maly's  Jaliresber.,  Bdd.  15  and  16. 
'  Vircliow's  Arch.,  Bd.  101. 

2  Om.  Ventrikelfordojelsen  lios  sunde  Mennesker,  Kjobenhavn,  1888.  See 
Maly's  Jahresber.,  Bd.  19. 


278  DIGESTION. 

contents  of  the  stomach  show  chiefly  the  presence  of  lactic  acid. 
Such  persons  digest  large  amounts  of  carbohydrates,  while  the- 
digestion  of  albuminous  bodies  is  decreased.  From  recent  investi- 
gations, making  use  of  his  new  method  of  estimating  lactic  acid. 
Boas  '  considers  that  after  partaking  of  carbohydrates  lactic  acid 
does  not  occur  in  the  stomach  under  normal  conditions  nor  during 
the  continual  lack  of  hydrochloric  acid.  Lactic  acid,  on  the  con- 
trary, is  regularly  found  in  carcinoma. 

The  FATS  which  are  not  fluid  at  the  ordinary  temperature  melt 
in  the  stomach  at  the  temperature  of  the  body  and  become  fluid. 
In  the  same  way  the  fat  of  the  fatty  tissues  is  set  free  in  the 
stomach  by  the  gastric  juice  which  digests  the  cell-membrane.  The 
gastric  juice  itself  seems  to  have  no  action  on  fats.^  The  soluble 
salts  of  the  food  naturally  are  found  dissolved  in  the  liquids  of  the 
contents  of  the  stomach;  but  the  insoluble  salts  may  also  be  dis- 
solved by  the  acid  of  the  gastric  juice. 

Since  the  hydrochloric  acid  of  the  gastric  juice  prevents  the 
contents  of  the  stomach  from  fermenting  with  the  generation  of 
gas,  those  gases  which  occur  in  the  stomach  probably  depend,  at 
least  in  great  measure,  upon  the  swallowed  air  and  saliva,  and  upon 
those  gases  generated  in  the  intestine  and  returned  through  the 
pyloric  valve.  Planer'  found  in  the  stomach-gases  of  a  dog 
66-68^  N,  25-33/^  CO,,  and  only  a  small  quantity,  0.8-6. 1^  of 
oxygen.  Schierbeck  ^  has  shown  that  a  part  of  the  carbon  di- 
oxide is  formed  by  the  mucous  membrane  of  the  stomach.  The 
tension  of  the  carbon  dioxide  in  the  stomach  corresponds,  accord- 
ing to  him,  to  30-40  mm.  Hg  in  the  fasting  condition.  It  increases 
after  partaking  food,  independently  of  the  kind  of  food,  and  may 
rise  to  130-140  mm.  Hg  during  digestion.  The  curve  of  the  carbon- 
dioxide  tension  in  the  stomach  is  the  same  as  the  curve  of  acidity 
in  the  different  phases  of  digestion,  and  Schieebeck  has  also  found 
that  the  carbon-dioxide  tension  is  considerably  increased  by  pilo- 
carpin,  but  diminished  by  nicotin.  According  to  him,  the  carbon 
dioxide  of  the  stomach  is  a  product  of  the  activity  of  the  secretory 
cells. 

'  Berlin,  klin.  Wochenschr.,  1895. 

"^  See  Contejean,  "  Sur  la  digestion  gastrique  de  lagraisse,"  Arch,  de  Physi- 
ologic, (5)  Bd.  6. 

3  Wien.  Sitzungsber.,  Bd.  42,  1860. 

*  Skan.  Arch.  f.  Physiol.,  Bdd.  3  and  5. 


DIGESTION  IN  THE  STOMACH.  27(> 

According  as  the  food  is  finely  or  coarsely  divided  it  passes 
sooner  or  later  through  the  pylorus  into  the  intestine.  From 
Busch's'  observations  on  a  human  intestinal  fistula,  it  required 
generally  15-30  minutes  after  eating  for  undigested  food,  such  as 
pieces  of  meat,  to  pass  into  the  upper  part  of  the  small  intestine. 
In  a  case  of  duodenal  fistula  in  a  human  being  observed  by 
KuHNE,'  he  saw,  ten  minutes  after  eating,  uncurdled  but  still 
coagulable  milk  and  small  pieces  of  meat  pass  out  of  the  fistula. 
The  time  in  which  the  stomach  unburdens  itself  of  its  contents 
depends,  however,  upon  the  rapidity  with  which  the  quantity  of 
hydrochloric  acid  increases,  for  it  seems  to  act  as  a  sort  of  irritant 
and  causes  the  opening  of  the  pylorus.  Many  other  conditions 
also  come  into  play,  namely,  the  activity  of  the  gastric  juice,  tlie 
quantity  and  character  of  the  food,  etc.,  etc.,  and  therefore  the 
time  required  to  empty  the  stomach  must  be  variable.  Richet* 
observed  in  a  case  of  stomachic  fistula  that  in  man  the  quantity  of 
food  which  is  in  the  stomach  the  first  three  hours  is  not  essentially 
changed,  but  that  in  the  course  of  a  quarter  of  an  hour  nearly  all 
is  driven  out,  so  that  only  a  small  residue  remains.  Kuhne  *  has 
made  about  the  same  observations  on  dogs  and  human  beings.  He 
found,  indeed,  in  dogs  that  in  the  first  nour  small  quantities  of 
meat  passed  into  the  intestine  every  ten  minutes  ;  but  he  also 
observed  that  in  dogs,  on  an  average,  about  five  hours  after  eating, 
in  man  somewhat  earlier,  a  free  emptying  into  the  intestine  takes 
place.  According  to  other  investigators,  the  emptying  of  the 
human  stomach  does  not  take  place  suddenly,  but  gradually. 
Beaumoxt"*  found  in  his  extensive  observations  on  the  Canadian 
hunter,  St.  Maktin,  that  the  stomach,  as  a  rule,  is  emptied  1^-5^ 
hours  after  a  meal,  depending  upon  the  character  of  the  food. 

The  time  in  wliich  different  foods  leave  the  stomach  depends 
also  upon  their  digestibility.  In  regard  to  the  unequal  digestibil- 
ity in  the  stomach  of  foods  rich  in  jjroteids,  which  really  form  the 
object  of  the  action  of  the  gastric  juice,  a  distinction  must  be  made 
between  the  rapidity  with  whicli  the  proteids  are  converted  into 
albumoses  and  peptones  and  the  rapidity  with  which  the  food  is 

'  Vircliow's  Arch.,  Bd.  14. 

*  Lelirbuch  d.  pliysiol.  Chem.,  S.  53. 

»L   c. 

^  Ihid. 

^Ibid. 


280  DIGESTION. 

converted  into  chyme,  or  at  least  so  prepared  that  it  may  easily 
pass  into  the  intestine.  This  distinction  is  especially  important 
from  a  practical  standpoint.  When  a  proper  food  is  to  bo  decided 
upon  in  cases  of  diminished  stomachic  digestion,  it  is  important  to 
select  snch  foods  as,  independent  of  the  difficulty  or  ease  with 
Tvhich  their  proteid  is  peptonized,  leave  the  stomach  easily  and 
quickly,  and  which  require  as  little  action  as  possible  on  the  part 
of  this  organ.  From  this  point  of  view  those  foods,  as  a  rule,  are 
most  digestible  which  are  fluid  from  the  start  or  may  be  easily 
liquefied  in  the  stomach  ;  but  these  foods  are  not  always  the  most 
digestible  in  the  sense  that  their  proteid  is  most  easily  peptonized. 
As  an  example,  hard-boiled  white  of  egg  is  more  easily  peptonized 
than  fluid  white  of  egg  at  a  degree  of  acidity  of  1-2  p.  m,  HCl  ;^ 
nevertheless  we  consider,  and  Justly,  that  an  unboiled  or  soft-boiled 
egg  is  easier  to  digest  than  a  hard-boiled  one.  Likewise  uncooked 
meat,  when  it  is  not  chopped  very  fine,  is  not  more  quickly  but 
more  slowly  peptonized  by  the  gastric  juice  than  the  cooked,  but  if 
it  is  divided  sufficiently  fine  it  is  often  more  quickly  peptonized 
than  the  cooked. 

The  greater  or  less  facility  with  which  the  different  albuminous 
foods  are  peptonized  by  the  gastric  juice  lias  been  comparatively 
little  studied,  and  as  the  conditions  in  the  stomach  are  more  com- 
plicated, results  obtained  with  artificial  gastric  juice  are  often  of 
no  value  for  the  practising  physician  and  should  in  any  case  be 
used  only  with  the  greatest  caution.  Under  these  circumstances 
we  cannot  enter  more  deeply  into  this  subject,  but  the  reader  is 
referred  to  text-books  on  dietetics  and  the  study  of  foods. 

As  our  knowledge  of  the  digestibility  of  the  different  foods  in 
the  stomach  is  slight  and  dubious,  so  also  our  knowledge  of  the 
action  of  other  bodies,  such  as  alcoholic  drinks,  bitter  principles, 
spices,  etc.,  on  the  natural  digestion  is  very  uncertain  and  imper- 
fect. The  difficulties  which  stand  in  the  way  of  this  kind  of  in- 
vestigation are  very  great,  and  therefore  the  results  obtained  thus 
far  are  often  ambiguous  or  conflict  with  each  other.  For  example, 
certain  investigators  have  observed  that  small  quantities  of  alcohol 
or  alcoholic  drinks  do  not  prevent  but  rather  facilitate  digestion ; 
others  observe  only  a  disturbing  action;  while  other  investigators 
believe  to  have  found  that  the  alcohol  first  acts  somewhat  as  a  dis- 

•  Wawrinsky,  Upsala  Lakarefs.  Forli.,  Bd.  8;  see  also  Maly's  Jahresber., 
Bd.  3. 


THE  STOMACH  AS  A  DIGESTIVE  ORGAN.  281 

turbing  agent,  but  afterwards,  when  it  is  absorbed,  it  produces  an 
abundant  secretion  of  gastric  juice,  and  thereby  facilitates  digestion 
(Gluzinski,'  Chittenden '). 

The  digestion  of  sundry  foods  is  not  dependent  on  one  organ 
alone,  but  divided  among  several.  For  this  reason  it  is  to  be 
expected  that  the  various  digestive  organs  can  act  for  one  another 
to  a  certain  point,  and  that  therefore  the  work  of  the  stomach 
could  be  taken  up  more  or  less  by  the  intestine.  This  in  fact  is 
the  case.  Thus  the  stomach  of  a  dog  has  been  almost  completely 
extirpated  (Czerny,"  Carvallo,  and  Paxchox  ^),  and  also  that 
part  necessary  in  the  digestive  process  has  been  eliminated  by 
plugging  the  pyloric  opening  (Ludwig  and  Ogata  ^),  and  in  both 
cases  it  was  possible  to  keep  the  animal  alive,  well  fed,  and  strong. 
In  these  cases  it  is  evident  that  the  digestive  work  of  the  stomach 
was  taken  up  by  the  intestine.  That  the  stomach  nevertheless, 
during  normal  conditions,  bears  an  essential  part  of  the  process  of 
digestion  may  be  inferred  from  the  fact  that  the  products  of  pro- 
teolysis can  generally  be  detected  in  the  contents  of  the  human 
stomach  even  shortly  after  a  meal.  By  tests  on  dogs  that  had  been 
given  meat-powder,  Cahn  °  found  large  quantities  of  peptone  in 
the  stomach,  and  this  progressed  to  the  same  extent  as  the  diges- 
tion,  although    absorption    took    place,    as    shown    by    Schmidt- 

MULHEIM.' 

It  is,  however,  quite  generally  assumed  that  no  peptonization 
of  the  proteids  worth  mentioning  occurs  in  the  stomach,  and  that 
tlie  albuminous  foods  are  only  prepared  in  the  stomach  for  the  real 
digestive  processes  in  the  intestine.  That  the  stomach  serves  in 
the  first  place  as  a  storeroom  follows  from  its  shape,  and  this  func- 
tion is  of  special  value  in  certain  new-born  animals,  for  instance  in 
dogs  and  cats.  In  these  animals  the  secretion  of  the  stomach  con- 
tains only  hydrochloric  acid  but  no  pepsiUj  and  the  casein  of  the 
milk  is  converted  by  the  acid  alone  into  solid  lumps  or  a  solid 
coagulum  which  fills  the  stomach.    Small  jDortions  of  this  coagulum 

1  Deutsch.  Arch.  f.  klin.  Med.,  Bd.  .39. 
^  Centralbl.  f.  d.  med.  Miss.,  1889,  S.  435. 

3  Czerny,  Beitrage  zur  operativeu  Cbirurgie.  Stuttgart,  1878.  Cited  from 
Bunge,  Lehrbucli  der  pbysiol    u.  path.  Chem. ,  p.  150. 

*  Arch,  de  pbysiol.,  (5)  Tome  7,  p.  106. 

*  Du  Bois-Reymond's  Arcb,  1883. 
«  Zeitscbr.  f.  klin.  Med.,    Bd.  12. 

">  Du  Bois-Reymond's  Arch.,  1879,  S.  39. 


282  DIGESTION. 

pass  in  to  the  intestine  only  little  by  little,  and  an  overburdening  of 
the  intestine  is  thus  prevented.  In  other  animals,  such  as  the  snake 
and  certain  fishes,  which  swallow  their  food  entire,  it  is  certain  that 
the  major  part  of  the  process  of  digestion  takes  place  in  the  stomach. 
The  importance  of  the  stomach  in  digestion  cannot  at  once  be 
decided.  It  varies  for  different  animals,  and  it  may  vary  in  the 
same  animal,  depending  upon  the  division  of  the  food,  the  rapidity 
with  which  the  peptonization  takes  place,  the  more  or  less  rapid 
increase  in  the  amount  of  hydrochloric  acid,  and  so  on. 

It  is  a  well-known  fact  that  the  contents  of  the  stomach  may  be 
kept  without  decomposing  for  some  time  by  means  of  hydrochloric 
acid,  while,  on  the  contrary,  when  the  acid  is  neutralized  a  fer- 
mentation commences  by  which  lactic  acid  and  other  organic  acids 
are  formed.  The  hydrochloric  acid  of  the  gastric  juice  has  unques- 
tionably an  anti-fermentive'  action,  and  also,  like  dilute  mineral 
acids,  an  antiseptic  action.  This  action  is  of  importance,  as  many 
disease  micro-organisms  may  be  destroyed  by  the  gastric  juice. 
The  comma  bacillus  of  cholera  is  killed  by  the  normal  acid  gastric 
juice,  while  if  it  is  introduced  into  the  stomach  after  an  injection 
of  a  soda  solution  it  may  remain  active.  Also  varieties  of  pyogenic 
streptococcus  and  the  staphylococcus  pyog.  aureus  are  killed  by  the 
acid  gastric  juice.  Still  the  gastric  juice  does  not  act  on  all  micro- 
organisms, and  especially  in  the  state  of  spores  they  can  withstand 
its  action.  As  an  example,  the  tubercle-virus  is  not  destroyed  by 
the  gastric  juice,  and  the  spores  of  the  anthrax  bacteria  are  not 
always  destroyed  by  the  hydrochloric  ~acid  of  the  gastric  juice. ^ 

Because  of  this  action  ^  the  chief  importance  of  the  gastric  juice 
is  now  considered  to  be  its  antiseptic  action.  In  opposition  to  this 
view  Caevallo  and  Pachon  have  shown  in  a  dog  with  extirpated 
stomach  that  putrefying  meat  could  be  partaken  of  without  disturb- 
ing the  digestion. 

After  death,  if  the  stomach  still  contains  food,  digestion  goes  on 
of  itself  not  only  in  the  stomach,  but  also  in  the  neighboring  organs, 
during  the  slow  cooling  of  the  body.  This  leads  to  the  question, 
why  does  the  stomach  not  digest  itself  during  life  ?     Ever  since 

'  See  Kilbne's  Lebrbuch,  p.  57;  Bunge,  Lebrbucb,  pp.  143  and  152;  F. 
Cobn,  Zeitscbr.  f.  pbysiol.  Cbem.,  Bd.  14;    Hirscbfeld,  Pfluger's  Arcb.,  Bd.  47. 

"^  See  Falk,  Vircbow's  Arcb.,  Bd.  93;  E.  Frank,  Deutscb.  med.  Wocb- 
enscbr.,  1884,  No.  24;  R.  Kocb,  iUd.,  1884,  No.  45. 

^  Bunge,  ].  c.  ,  , 


ABNORMAL  STOMACHIC  DIGESTION.  283 

Pavy  '  has  shown  that  after  tying  the  smaller  blood-vessels  of  the 
stomach  of  dogs  the  corresponding  part  of  the  mucous  membraace 
was  digested,  efforts  have  been  made  to  find  the  cause  in  the 
neutralization  of  the  acid  of  the  gastric  juice  by  the  alkali  of  the 
blood.  That  the  reason  for  the  non-digestion  during  life  is  to  be 
sought  for  in  the  normal  circulation  of  the  blood  cannot  be  contra- 
dicted; but  it  is  more  probably  found  in  the  fact  that  the  living 
mucous  coat  nourished  by  the  alkaline  blood  shows  quite  different 
absorption,  diffusion,  and  filtration  properties  than  the  dead  mucous 
coat.     This  last  was  shown  long  ago  by  Eanke.^ 

Under  pathological  conditions  irregularities  in  the  secretion  as 
well  as  in  the  absorption  and  in  the  mechanical  work  of  the  stomach 
may  occur.  Pepsin  is  almost  always  present,  but  the  absence  of 
the  rennin,  as  above  stated,  may  occur  in  many  cases  (Boas, 
JoHisrsoN",  Klemperer').  In  regard  to  the  acid,  it  should  be 
mentioned  that  sometimes  this  secretion  may  be  increased  so  that 
an  abnormally  acid  gastric  juice  is  secreted,  and  sometimes  may  be 
decreased  so  that  little  or  hardly  any  hydrochloric  acid  is  secreted. 
A  hypersecretion  of  acid  gastric  juice  sometimes  occurs.  In  the 
secretion  of  too  little  hydrochloric  acid  the  same  conditions  appear 
as  after  the  neutralization  of  the  acid  contents  of  the  stomach  out- 
side of  the  organism.  Fermentation  processes  now  appear  in  which, 
besides  lactic  acid,  there  appear  also  volatile  fatty  acids,  such  as 
butyric  and  acetic  acids,  etc.,  and  gases  like  hydrogen.  These 
fermentation  products  are  therefore  often  found  in  the  stomach  in 
cases  of  chronic  catarrh  of  the  stomach,  which  may  give  rise  to 
belching,  pyrosis,  and  other  symptoms. 

Among  the  foreign  substances  found  in  the  contents  of  the 
stomach  we  have  urea,  or  ammonium  carbonate  derived  therefrom 
in  urasmia;  blood,  which  generally  forms  a  dark-brown  mass 
through  the  presence  of  haematin,  due  to  the  action  of  the  gastric 
juice;  bile,  which,  especially  during  vomiting,  easily  finds  its  way 
through  the  pylorus  into  the  stomach,  but  whose  presence  seems  to 
be  without  importance. 

If  it  is  desired  to  test  the  gastric  juice  or  the  contents  of  the 
stomach  iov  pepsin,  fibrin  may  be  employed.     If  this  is  thoroughly 

'  Plailos.  Transactions,  Vol.  153,  Part  1,  and  Guy's  Hospital  Reports, 
Vol.  13. 

2  See  Ranke,  Grundziige  der  Pliysiol.,  3.  Aufl.,  1875,  S.  111-120. 
»  See  foot-note,  p.  273. 


'264:  DIGESTION. 

-washed  immediately  after  beating  the  blood,  well  pressed  and  placed 
in  glycerin,  it  may  be  kept  in  serviceable  condition  an  indefinitely 
loQg  time.  The  gastric  juice  or  the  matter  contained  in  the 
stomach — the  latter,  if  necessary,  having  been  previously  diluted 
with  1  p.  m.  hydrochloric  acid — is  filtered  and  tested  with  fibrin  at 
ordinary  temperature.  (It  must  not  be  forgotten  that  a  control 
test  must  be  made  with  acid  alone  and  another  portion  of  the  same 
fibrin.)  If  the  fibrin  is  not  noticeably  digested  within  one  or  two 
honrs,  no  pepsin  is  present,  or  at  most  there  are  only  slight  traces. 

In  testing  for  re^min  the  liquid  must  be  first  carefully  neutral- 
ized. To  10  c.  c.  unboiled  amphoteric  (not  acid)  reacting  cow's 
milk  add  1-2  c.  c.  of  the  filtered  neutralized  liquid;  but  care  mnst 
be  taken  not  to  add  too  much  of  the  liquid  from  the  stomach,  for 
the  coagulation  may  be  retarded  or  prevented  by  diluting  the  milk. 
In  the  presence  of  rennin  the  milk  should  coagulate  to  a  solid  mass 
at  the  temperature  of  the  body  in  the  course  of  10-20  minutes 
without  changing  its  reaction.  If  the  milk  is  diluted  too  much  by 
the  addition  of  the  liquid  of  the  stomach,  only  coarse  flakes  are 
obtained  and  no  solid  coagulum.  Addition  of  lime-salts  is  to  be 
avoided,  as  they  in  great  excess  may  produce  a  partial  coagulation 
eveu  in  the  absence  of  rennin. 

In  many  cases  it  is  especially  important  to  determine  the  degree 
of  acidity  of  the  gastric  juice.  This  may  be  done  by  the  ordinary 
titration  methods.  Phenol  phthalein  must  not  be  used  as  an  indi- 
cator, for  we  get  too  high  results  in  the  presence  of  large  quantities 
of  proteids.  Good  results  may  be  obtained,  on  the  contrary,  by 
using  very  delicate  litmus-paper.  As  the  acid  reaction  of  the  con- 
tents of  the  stomach  may  be  caused  simultaneously  by  several  acids, 
still  the  degree  of  acidity  is  here,  as  in  other  cases,  expressed  in  only 
one  acid,  e.g.,  HCl.     G-enerally  the  acidity  is   expressed   by  the 

number  of  c.  c.  of   --  caustic  soda  which  is  required  to  neutralize 

the  several  acids  in  100  c.  c.  of  the  liquid  of  the  stomach.  An 
acidity  of  43^  means  that  100  c.  c.  of  the  liquid  of  the  stomach 

isr  .    . 

required  43  c.  c.  of  -—  caustic  soda  to  neutralize  it. 

The  acid  reaction  may  be  partly  due  to  free  acid,  partly  to  acid 
salts  (monophosphates),  and  partly  to  both.  According  to  Leo  '  we 
can  test  for  acid  phosphates  by  calcium  carbonate,  which  is  not 
neutralized  therewith,  while  the  free  acids  are.  If  the  gastric  con- 
tent has  a  neutral  reaction  after  shaking  with  calcium  carbonate 
and  the  carbon  dioxide  is  driven  out  by  a  current  of  air,  then 
it  contains  only  free  acid;  if  it  has  an  acid  reaction,  then  acid  phos- 
phates are  presen  t ;  and  if  it  is  less  acid  than  before,  it  contains 

'  Centralbl.  f.  d.  med.  Wissenscb.,  1889,  S.  481,  and  Diagnostik  der  Krank- 
heiten  der  Verdauungsorgane  (Berlin,  1890)  ;  also  Pfliiger's  Arch.,  Bd.  48,  S. 
614. 


DETECTION  OF  ACID  IX  THE  STOMACH.  285 

botli  free  acid  and  acid  2:)liospliate.  This  method  can  also  be  apjilied 
in  the  estimation  of  free  acid  (see  below). 

It  is  also  important  to  be  able  to  ascertain  the  nature  of  the  acid 
or  acids  occurring  in  the  contents  of  the  stomach.  For  this  pur- 
pose, and  especially  for  the  dctecfion  of  free  hydrochloric  acid,  a 
great  number  of  color  reactions  have  been  proposed,  which  are  all 
based  upon  the  fact  that  the  coloring  substance  gives  a  character- 
istic color  with  very  small  quantities  of  hydrochloric  acid,  while 
lactic  acid  and  the  other  organic  acids  do  not  give  these  colorations, 
or  only  in  a  certain  concentration,  which  can  hardly  exist  in  the 
contents  of  the  stomach.  These  reagents  are  a  mixture  of  ferric 
ACETATE  and  POTASSIUM  suLPHOCYAXiDE  solution  (Mohr's  reagent 
has  been  modified  by  several  investigators),  methtlaistilix- violet, 

TROPiEOLIX    00,    COXGO   RED,    MALACHITE-GREEX,    PHLOROGLUCIX- 

VAXiLLix,  BEXZOPURPURix  6  B,  and  others.  As  reagents  tov  free 
lactic  acid  Uffelmaxx  suggests  a  strongly  diluted,  amethyst-blue 
solution  of  FERRIC  CHLORIDE  and  CARBOLIC  ACID  Or  a  strongly 
diluted,  nearly  colorless  solution  of  ferric  chloride.  These  give 
a  yellow  with  lactic  acid,  but  not  with  hydrochloric  acid  or  with 
volatile  fatty  acids.  Instead  of  the  untrustworthy  lactic-acid  reac- 
tion of  Uffelmaxx,  Boas  '  makes  use,  in  the  detection  and  estima- 
tion of  lactic  acid,  of  the  property  of  lactic  acid  of  being  oxidized 
into  aldehyde  and  formic  acid  on  careful  oxidation  with  sulphuric 
acid  and  manganese  dioxide.  The  aldehyde  is  detected  by  its 
forming  iodoform  w'ith  an  alkaline  iodine  solution  or  by  its  forming 
aldehyde   mercury   with    Xessler's    reagent.       The    quantitative 

N 
estimation  consists  in  the  formation    of  iodoform  with  — r  iodine 

10 

solution  and  caustic  potash,  adding  an  excess  of  hydrochloric  acid 

and  titrating  with  a  —^  sodium  arsenite  solution  and   retitrating 
^10  * 

with  iodine  solution,  after  the  addition  of  starch-j)aste,  until  a  blue 
coloration  is  obtained. 

The  value  of  these  reagents  in  testing  for  free  hydrochloric  acid 
or  lactic  acid  is  still  disputed.^  Among  the  reagents  for  free  hydro- 
chloric acid,  Mohr's  test  (even  though  not  very  delicate),  Guxz- 
burg's  test  with  phloroglucin-vanillin,  and  the  test  with  tropa3olin 
00,  performed  in  moderate  heat  as  suggested  by  Boas,  seem  to  be 
the  most  valuable.  If  these  tests  give  positive  results,  then  the 
presence  of  hydrochloric  acid  may  be  considered  as  proved.  A 
negative  result  does  not  eliminate  the  presence  of  hydrochloric  acid, 
as  the  delicacy  of  these  reactions  has  a  limit,  and  also  the  simul- 
taneous presence  of  proteid,  peptones,  and  other  bodies  influences 

'  Deutscli.  med.  Woclieusclir.,  1893,  and  Miincliener  med.  Wochensclir., 
1893. 

-  In  regard  to  the  extensive  literature  on  this  question  we  refer  to  v. 
Jaksch,  Klinische  Diagnostik  innerer  Krankbeiten,  4.  Aufl.,  1896,  Section  5. 


286  DIGESTION. 

the  reactions  more  or  less.  The  reactions  for  lactic  acid  may  also 
give  negative  results  in  the  presence  of  comparatively  large  quanti- 
ties of  hydrochloric  acid  in  the  liqnid  to  be  tested.  Sugar,  sulpho- 
cyanides,  and  other  bodies  may  act  with  these  reagents  similarly  to 
lactic  acid. 

In  order  to  be  able  to  correctly  judge  of  the  value  of  the  differ- 
ent reagents  for  free  hydrochloric  acid,  it-  is  naturally  of  greatest 
importance  to  be  clear  in  regard  to  what  we  mean  by  free  hydro- 
chloric acid.  It  is  a  well-known  fact  that  hydrochloric  acid  com- 
bines with  proteids,  and  a  considerable  part  of  tlie  hydrochloric  acid 
may  therefore  exist  in  the  contents  of  the  stomach,  after  a  meal  rich 
in  proteids,  in  combination  with  proteids.  This  hydrochloric  acid 
combined  with  proteids,  as  well  as  that  which  is  combined  with 
amido-acids,  cannot  be  considered  as  free,  and  it  is  for  this  reason 
that  certain  investigators  consider  such  methods  as  those  of  Leo 
and  Sjoqvist,  which  will  be  described  below,  as  of  little  value. 
However,  it  must  be  remarked  that,  according  to  the  unanimous 
experience  of  many  investigators,  the  hydrochloric  acid  combined 
with  proteids  and  also  that  combined  with  amido-acids  (Salkowski 
and  KuMAGAWA  ')  is  physiologically  active.  Those  reactions  (color 
reactions)  which  only  respond  to  actually  free  hydrochloric  acid  do 
not  show  the  physiologically  active  hydrochloric  acid.  The  sugges- 
tion of  determining  the  "  physiologically  active  "  hydrochloric  acid 
instead  of  the  "  free  "  seems  to  be  correct  in  principle;  and  as  the 
conceptions  of  free  and  physiologically  active  hydrochloric  acid  do 
not  cover  one  another  we  must  always  be  clear,  if  we  want  to 
determine  the  actually  free  or  the  physiologically  active  hydrochloric 
acid,  before  we  judge  of  the  value  of  a  certain  reaction. 

As  the  above-mentioned  reactions  for  hydrochloric  acid  and 
organic  acids  are  not  sufficient  in  exact  investigations,  still  they 
may  serve  in  many  cases  for  clinical  purposes,  and  it  will  suffice  to 
refer  the  reader  to  other  text-books,  aad  especially  to  '"'' Klinisclie, 
Diagnostih  innerer  KranJcheiten^''^  by  E.  v.  Jaksch,  4th  edition, 
1896,  for  the  performance  and  the  relative  value  of  these  tests. 

Among  the  many  methods  suggested  for  the  quantitative  esti- 
mation of  hydrochloric  acid  not  combined  with  inorganic  bases,  the 
two  following  are  the  most  trustworthy. 

The  method  of  K.  Morner  and  Sjoqvist  depends  on  the  fol- 
lowing principle:  When  the  gastric  juice  is  evaporated  to  dryness 
with  barium  carbonate  and  then  calcined  the  organic  acids  burn  up 
and  give  insoluble  barium  carbonate,  while  the  hydrochloric  acid 
forms  soluble  barium  chloride.  From  the  quantity  of  this  the 
original  amount  of  hydrochloric  acid  can  be  calculated.  10  c.  c.  of 
the  filtered  contents  of  the  stomach  is  mixed  in  a  small  platinum 
or  silver  dish  with  a  knife-point  of  barium  carbonate  free  from 
chlorides,  and  evaporated  to  dryness.     The  residue  is  burnt  and 

1  Virchow's  Arcli.,  Bd.  132. 


ESTIMATION  OF  ACID  IX  THE  STOMACH.  287 

allowed  to  glow  for  a  few  minutes.  The  cooled  carbon  is  gently 
rnbbed  with  water  and  completely  extracted  with  boiling  water, 
and  the  filtrate  (about  50  c.  c.)  treated  with  an  equal  volume  of 
alcohol  and  3-4  c.  c.  sodium  acetate  solution  {10 fo  acetic  acid  and 
lOfo  acetate).  The  amount  of  barium  in  the  filtrate  is  determined 
by  titration  with  a  solution  of  potassium  bichromate,  in  which  the 
alcohol  facilitates  the  precipitation  of  the  barium  chromate,  while 
the  acetate  prevents  in  part  the  precipitation  of  the  calciuum  car- 
bonate and  in  part  the  setting  free  of  hydrochloric  acid.  The 
potassium-bichromate  solution  should  contain  about  8.5  grms. 
potassium  bichromate  to  the  litre.     Its  titre  must  exactly  corre- 

spond  with  an  —  barium-chloride  solution,  and  the  procedure  is  the 

same  as  in  the  titration  of  the  BaCl^  solution  obtained  from  the 
contents  of  the  stomach.  A  paper  moistened  with  tetramethylpara- 
phenylendiamin  is  used  as  indicator;  this  is  colored  blue  by  a 
bichromate  in  acetic-acid  solution.  In  titrating  we  add  chromate 
solution  as  long  as  tlie  barium  chromate  precipitated  does  not 
apparently  increase,  then  test  with  the  indicator-paper  after  each 
addition  until  it  gives  a  decided  blue  coloration  within  one  minute, 
and  stop  adding  chromate  solution.     As  the  titre  of  the  chromate 

solution  has  been  determined  by  an  —  BaCl^  solution,  it  is  easy  to 

calculate  the  quantity  of  HCl  in  10  c.  c.  of  the  gastric  juice  corre- 
sponding to  the  number  of  c.  c.  of  the  chromate  solution  used.  If 
the  total  acidity  is  determined  in  a  second  portion  of  the  gastric 
juice,  then  the  quantity  of  lactic  acid  or  other  organic  acids  repre- 
sented as  HCl  may  be  calculated.  v.  Jaksch  suggests  precipi- 
tating the  barium  with  sulphuric  acid  and  weighing  the  sulphate 
instead  of  titrating.  Sjoqvist  '  has  modified  his  method  of  deter- 
mining hydrochloric  acid  by  precipitating  the  solution  of  BaCl^  by 
ammonium  chromate  in  the  presence  of  acetic  acid.  This  precipi- 
tate is  dissolved  in  water  by  the  aid  of  a  little  HCl,  then  titrated 
with  a  potassium-iodide  solution  and  hydrochloric  acid,  and  now 
titrated  with  sodium  hyposulphite.  The  reactions  take  place  as 
follows:  4HC1  +  2BaC03  =  3BaCl,  -f  2H.,0  +  2C0,;  2BaCl,  + 
2(NHJ,CrO,  =  2BaCrO,  +  4NH,C1;  2BaCrO,  -f  16HC1  +  6KI  = 
2BaCl,  +  Cr,Cl,  +  8H,0  +  6KC1  -f  31,;  and  31,  +  GNa^S^O,  = 
6NaI  -\-  3Na,S^0,.  Each  c.c.  of  the  hyposulphite  corresponds  to 
3  mgm.  HCl.  Other  modifications  of  this  method  have  been  pro- 
posed by  Salkowski  and  Fawitzki,"  Boas,'  and  Bourget.'  This 
method  of  Morner-Sjoqvist  gives,  according  to  Leo  '  and  Koss- 

'  Skan.  Arch.  f.  Physiol.,  Bd.  5. 

«  Virchow's  Arch.,  Bd.  123. 

»  Centralbl.  f.  klin.  Med.,  Bd.  12. 

*  Schmidt's  Jahrbilcher,  1891,  Bd.  229  (Reference). 

'L.  c. 


288  DIGESTION. 

lee/  in  the  presence  of  phosphates,  too  low  valnes,  but  it  is  other- 
Avise  very  good. 

Leo's  Method.'^  10  c.  c.  of  the  filtered  gastric  juice  is  treated 
with  about  5  c.  c.  calcium-chloride  solution,  and  the  total  acidity 

N  . 

determined,  by  — r  caustic-soda  solution,  using  litmus  as  the  indi- 
■^10  '  o 

cator.  Then  shake  15  c.  c.  of  the  same  gastric  juice  with  pure, 
finely  powdered  calcium  carbonate,  filter  through  a  dry  filter, 
remove  the  carbon  dioxide  from  the  filtrate  by  means  of  a  current 
of  air,  measure  ofi  exactly  10  c.  c.  of  the  liquid  and  treat  with 
5  c.  c.  of  the  calcium-chloride  solution,  and  add  litmus  and  titrate 
again.  The  difference  between  the  two  titrations  shows  the  acidity 
due  to  free  acid.  Any  fatty  acids  present  may  be  shaken  out  from 
another  portion  by  ether  and  the  acidity  determined  on  the  spon- 
taneous evaporation  of  the  ether. 

By  determining  the  electrical  resistance  Sjoqtist  has  been  able 
to  determine  the  amount  of  actually  free  acid  and  that  combined 
with  alkali  in  a  mixture  of  hydrochloric  acid  and  alkali  monophos- 
phate. He  finds  that  the  quantity  of  hydrochloric  acid  found  by 
Mokner-Sjoqtist's  method  in  such  mixtures  corresponds  very 
closely  to  the  quantity  actually  present.  He  upholds  his  method, 
in  opposition  to  Leo's  method,  which,  according  to  him,  does  not 
give  accurate  results  for  free  acid. 

Other  methods  have  been  proposed  by  Cahx  and  t.  Merixg, 
HoFFMAXX,  WiXTER  and  Hayem,  and  Braux.  According  to 
Kossler  '  the  three  last-mentioned  methods  are  not  quite  service- 
able. 

In  testing  for  volatile  fatty  acids  the  contents  of  the  stomach 
should  not  be  directly  distilled,  as  volatile  fatty  acids  may  be 
formed  by  the  decomposition  of  other  bodies,  such  as  proteid  and 
haemoglobin.  The  neutralized  contents  of  the  stomach  are  there- 
fore precipitated  with  alcohol  at  ordinary  temperature,  filtered 
quickly,  pressed,  and  repeatedly  extracted  with  alcohol.  The  alco- 
holic extracts  are  made  faintly  alkaline  by  soda,  and  the  alcohol 
distilled.  The  residue  is  now  acidified  by  sulphuric  or  phosphoric 
acid  and  distilled.  The  distillate  is  neutralized  by  soda  and.  evap- 
orated to  dryness  on  the  water-bath.  The  residue  is  extracted  with 
absolute  alcohol,  filtered,  the  alcohol  distilled  off,  and  this  residue 
dissolved  in  a  little  water.  This  solution  may  be  directly  tested  for 
acetic  acid  with  sulphuric  acid  and  alcohol  or  with  ferric  chloride. 
Formic  acid  may  be  tested  for  by  silver  nitrate,  which  quickly  gives 
a  black  precip)itate;  and  butyric  acid  is  detected  by  the  odor  after 
the  addition  of  an  acid.     In  regard  to  the  methods  for  more  fully 

'  Zeitschr.  f.  physiol.  Chem.,  Bd.  17. 
2L.  c. 

2  L.  c. ;  see  also  Mizerski  andL.  Xencki,  Arch,  des  sciences  biologiques,  St. 
Petersbourg,  Tome  1. 


INTESTINAL  JUICE,  289 

investigating  the  different  volatile  fatty  acids,  the  reader  is  referred 
to  other  text-books. 


III.  The  Glands  of  the  Mucous  Membrane  of  the 
Intestine  and  their  Secretions. 

The  Secretion  of  Brunner's  Glands.  These  glands  are  partly- 
considered  as  small  pancreas  glands  and  partly  as  mucous  or  salivary 
glands.  Their  importance  in  various  animals  is  different.  Accord- 
ing to  Grutznek,'  in  dogs  they  are  closely  related  to  the  pyloi'ic 
glands  and  contain  pepsin.  The  statements  in  regard  to  the  occur- 
rence of  a  diastatic  enzyme  are  contradictory,  and  the  difficulty  of 
collecting  the  secretion  from  these  glands  free  from  contamination 
makes  these  assumptions  somewhat  unreliable. 

The  Secretion  of  Lieberkuhn's  Glands.  The  secretion  of  these 
glands  has  been  studied  by  the  aid  of  a  fistula  in  the  intestine 
according  to  the  method  of  Thiry*  and  Vella.°  Very  little  if 
any  secretion  takes  place  in  fasting  animals  (dog)  when  the  mucous 
membrane  is  not  irritated.  The  secretion  begins  in  the  first  hour 
after  partaking  of  food,  bat  the  maximum  varies  witli  the  quantity 
and  character  of  the  food.^  Mechanical,  chemical,  or  electrical 
irritation  excites  a  secretion  or  increases  that  already  begun 
(Thiry).  Laxatives  do  not  increase  the  secretion,  while  pilocarpin 
produces  a  very  abundant  one  (Masloff  ^  and  Vella).  The 
quantity  of  this  secretion  in  the  course  of  24  hours  has  not  been 
exactly  determined. 

In  the  upper  part  of  the  small  intestine  of  the  dog  this  secretion 
is  scanty,  slimy,  and  gelatinous;  in  the  lower  part  it  is  more  fluid, 
with  gelatinous  lumps  or  flakes  (Rohmann  °).  Intestinal  juice  has 
a  strong  alkaline  reaction,  generates  carbon  dioxide  on  the  addition 
of  an  acid,  and  contains  (in  dogs)  nearly  a  constant  quantity  of 
NaCl  and  Na^COg,  4.8-5  and  4-5  p.  m.  respectively  (Gumilewski,^ 
Eohmann).  It  contains  proteid  (Thiry  found  8.01  p.  m.),  the 
quantity  decreasing  with  the   duration  of  the  elimination.     The 

'  Pfliiger's  Arch.,  Bd.  12. 
'  Wien.  Sitzungsber.,  Bd.  50. 

*  Moleschott's  Untersucb.,  Bd.  13. 

*  See  Heidenbain  in  Hermann's  Handbuch,  Bd.  5,  Th.  1,  S.  170. 
'  Cited  from  Heidenbain,  ibid.,  S.  171. 

«  Piiiiger's  Arch.,  Bd.  41. 
•>  Ibid.,  Bd.  39. 


290  DIGESTION. 

quantity  of  solids  varies.  In  dogs  the  quantity  of  solids  is  12.2- 
2-4.1  p.  m.,  and  in  slieep  46-47  p.  m.  The  specific  gravity  of  the 
intestinal  juice  of  the  dog,  according  to  the  observations  of  Thiry, 
is  1.010-1.0107. 

The  action  of  the  intestinal  juice  has  been  studied  by  many 
investigators,  but  the  statements  concerning  it  are  at  variance. 
According  to  certain  experimenters  it  has  the  power  of  converting 
starch  into  sugar,  but  others  claim  that  it  has  not  the  property. 
However,  it  seems  generally  accepted,  as  shown  by  Paschutin,' 
Browx  and  Herok,"  Bastianelli,"  and  others,  that  the  intestinal 
juice  or  an  infusion  of  the  mucous  membrane  has  an  inv^erting 
action  on  cane-sugar  or  maltose.  This  has  been  further  confirmed 
by  MiUEA,  Pawtz  and  Vogel.'  Lactose  does  not  seem  to  be 
inverted  by  the  intestinal  juice  in  the  absence  of  micro-organisms.* 
The  action  on  carbohydrates  takes  place  more  quickly  and  to  a 
greater  extent  in  the  upper  part  of  the  intestine,  and  correspond- 
ingly the  absorption  of  starch  and  sugar  occurs  more  quickly  in  the 
•upper  part  than  in  the  lower  section  of  the  intestine  (Lai^nois  and 

LePI]!^'E,°  R0HMAN"]sr). 

Intestinal  juice  does  not  split  neutral  fats,  but  it  has  the  prop- 
erty, like  other  alkaline  fluids,  of  emulsifying  the  fats.  In  regard 
to  its  action  on  albuminous  bodies  most  investigators  agree  that  the 
intestinal  juice  has  no  action  on  boiled  proteid  or  meat,  while  it 
dissolves  fibrin  according  to  Thiry.  Albuvioses  are  not  converted 
into  peptones  (Wenz,'  Bastianelli).  Contrary  to  other  investi- 
gators, ScHiFF "  claims  t*hat  the  juice  from  a  successful  fistula  opera- 
tion digests  not  only  coagulated  proteid  and  lumps  of  casein,  but 
also  unboiled  and  boiled  meat.  The  lack  of  action  on  proteids 
which  was  observed  by  other  investigators  Schiff  attributes  to  the 
abnormal  juice  with  which  they  experimented.  Schiff  also 
obtained  from  an  operation  not  entirely  successful  a  juice  whose 


'  Centralbl.  f.  d.  med.  Wissenscli.,  1870,  S.  561. 
2  Annal.  d.  Chem.  u.  Pbarin.,  Bd.  204. 

5  Molescliott's  Untersucli.  zur  Naturlehre,  Bd.  14.      This  contains  all  the 
older  literature. 

*  Zeitschr.  f .  Biologie,  Bd.  33. 

'"  Voit  and  Lusk,  Zeitschr.  f.  Biologic,  Bd.  28. 

«  Arch,  de  Physiol.  (8)  Tome  1. 

■I  Zeitschr   f.  Biologie,  Bd.  22. 

«  Centralbl.  f.  d.  med.  Wissensch.,  1868,  S.  357. 


THE  PANCREAS.  291 

action  on  proteicl  and  meat  was  no  greater  than  that  studied  by 
Thiky  and  other  investigators. 

Human  intestinal  juice  in  a  case  of  mnis  prcBternaturalis  has 
been  investigated  by  Demant.'  This  juice  showed  itself  entirely 
inactive  on  albuminous  bodies,  even  on  fibrin  and  on  fats.  It  only 
had  a  very  faint  action  on  boiled  starch.  Tubby  and  Manning' 
have  investigated  human  intestinal  juice.  The  specific  gravity  was 
on  an  average  1.00G9.  The  reaction  was  alkaline,  and  an  abundant 
development  of  carbon  dioxide  took  place  on  adding  acid.  Proteids 
were  not  digested;  starch  was  first  saccharified  very  slowly,  while 
cane-sugar  and  maltose  were  inverted  by  the  juice.  Fats  were  both 
emulsified  and  saponified.  These  experiments  on  the  action  of  the 
intestinal  juice  on  food  introduced  into  the  intestine  in  cases  of 
isolated  loop  of  the  intestine  in  animals,  and  in  human  intestine  in 
cases  of  aims  prcBternaturalis,  have  not  given  any  positive  results, 
because  of  the  putrefaction  processes  going  on  in  the  intestine. 

The  secretion  of  the  glands  in  the  large  intestine  seems  to  con- 
sist chiefly  of  mucus.  Fistulas  have  also  been  introduced  into  these 
parts  of  the  intestine,  which  are  chiefly  if  not  entirely  to  be  consid- 
ered as  absorption  organs.  The  investigations  on  the  action  of  this 
secretion  on  nutritive  bodies  have  not  as  yet  yielded  any  positive 
results. 

IV.  Pancreas  and  Pancreatic  Jnice. 

In  invertebrates,  which  have  no  pepsin  digestion  and  which  also 
have  no  formation  of  bile,  the  pancreas,  or  at  least  an  analogous 
organ,  seems  to  be  the  essential  digestion  gland.  On  the  contrary, 
an  anatomically  characteristic  pancreas  is  absent  in  certain  verte- 
brates and  in  certain  fishes.  Those  functions  which  should  be  per- 
formed by  this  organ  seem  to  be  performed  in  these  animals  by  the 
liver,  which  may  be  rightly  called  hepatopancreas.  In  man  and 
in  most  vertebrates  the  formation  of  bile  and  of  certain  secretions 
containing  enzymes  important  for  digestion  is  divided  between  the 
two  organs,  the  liver  and  the  pancreas. 

The  pancreas  gland  is  similar  in  certain  respects  to  the  parotid 
gland.     The  secreting  elements  of  the  former  consist  of  nucleated 

'  Virchow's  Arch.,  Bd.  75. 

"^  Guy's  Hosp.  Report,  Vol.  48,  p.  277  ;  also  Ceutralbl.  f.  d.  med.  Wissensch., 
1892,  S.  945. 


2y2  DIGESTION. 

cells  whose  basis  forms  a  mass  ricli  in  proteids,  whicli  expand  ia 
water  and  in  which  two  distinct  zones  exist.  The  outer  zone  is 
more  homogeneous,  the  inner  cloudy  due  to  a  quantity  of  grannies. 
The  nucleus  lies  about  midway  between  the  two  zones,  bat  this 
position  may  change  with  the  varying  relative  size  of  the  two  zones. 
According  to  Heidenhain,'  the  inner  part  of  the  cells  diminishes 
in  size  during  the  first  stages  of  digestion,  in  which  the  secretion  is 
active,  while  at  the  same  time  the  outer  zone  enlarges  owing  to  the 
absorption  of  new  material.  In  a  later  stage,  when  the  secretion 
has  decreased  and  the  absorption  of  the  nutritive  bodies  has  taken 
place,  the  inner  zone  enlarges  at  the  expense  of  the  outer,  the  sub- 
stance of  the  latter  having  been  converted  into  that  of  the  former. 
Under  physiological  conditions  the  glandular  cells  are  undergoing; 
a  constant  change,  at  one  time  consaming  from  the  inner  part  and 
at  another  time  growing  from  the  outer  part.  The  inner  granular 
zone  is  converted  into  the  secretion,  and  the  outer,  more  homo- 
geneous zone,  which  contains  the  repairing  material,  is  then  con- 
verted into  the  granular  substance. 

Besides  considerable  quantities  of  proteids,  globulin,  nudeo- 
proteid  (see  Chapter  II),  and  alhumin,  we  find  in  this  gland  several 
enzymes,  or,  more  correctly,  zymogens,  which  will  be  described 
later.  We  also  find  in  this  gland  nuclem,  leucin  (butalanin),, 
tyrosm  (not  in  the  perfectly  fresh  gland),  xanthin,  1-8  p.  m., 
hypoxanthin,  3-4  p.  m.,  gtcani7i,  2-7.5  p.  m,  (all  figures  are  calcu- 
lated for  the  dried  substance,  Kossel''),  ademn,  tnosit,  lactic  acid, 
volatile  fatty  acids,  fats,  and  mineral  substances.  According  to  the 
investigations  of  Oidtmakn",'  the  human  pancreas  contains  745.3 
p.  m.  water,  245,7  p.  m.  organic  and  9.5  p.  m.  inorganic  sub- 
stances. 

The  purpose  of  the  pancreas  is  to  produce  very  important 
enzymes  for  digestion;  but  besides  this  it  also  has  another  very 
important  function.  As  already  stated  in  a  preceding  chapter,  it 
is  of  the  greatest  importance  in  metabolism,  namely,  for  the  trans- 
formation of  dextrose  in  the  animal  body.  In  this  regard  it  is  well 
known  that  in  dogs  and  certain  other  animals  (but  not  in  pigeons 
and  geese),  the  extirpation  of  the  gland  causes  a  marked  diabetes, 

1  Pfliiger's  Arch.,  Bd.   10. 

s  Zeitsclir.  f.  physiol.  Chem.,  Bd.  8. 

^v   Gorup-Besanez,  Lehrbucli,  4.  Aufl.,  S.  732. 


PANCREAS  AND  DIABETES.  293 

at  least  in  most  cases.  We  do  not  know  liow  this  diabetes  is 
brought  about. 

According  to  the  brothers  Cavazzani/  the  pancreas  diabetes  is 
not  caused  by  a  decreased  combustion  of  the  normal  quantity  of 
sugar  formed,  but  by  an  abnormal  increase  in  the  formation  of  sugar 
in  the  liver,  and  the  extirpation  of  the  pancreas  acts,  according  to 
them,  by  causing  a  lesion  of  the  plexus  coeliacus.  They  have  found 
that  irritation  of  this  plexus  j)roduced  an  increased  production  of 
sugar  in  the  liver,  and  they  claim  that  the  extirpation  of  the  pancreas 
induces  a  degenerative  irritation  of  the  plexus,  which  is  similar  to 
the  paralytic  secretion  in  the  salivary  glands.  In  opposition  to  this 
view  the  investigations  of  Minkowski,  Hedon",  Lancereaux, 
TiiiROLOix,''  and  others  have  been  presented,  namely,  tliat  on  sub- 
cutaneously  transplanting  a  portion  of  the  pancreas  the  function  of 
the  i^aucreas  in  transforming  or  producing  sugar  is  not  disturbed. 
After  tlie  removal  of  the  intra-abdominal  portion  of  the  gland  the 
animal  in  this  case  did  not  acquire  diabetes.  If  the  subcutaneously 
enveloped  portion  of  pancreas  is  further  removed,  then  an  elimina- 
tion of  sugar  of  great  intensity  takes  jjlace. 

Chauyeau  and  Kaufmans  '  are  of  the  opinion  that  after  the 
•extirpation  of  the  pancreas  an  abnormal  increase  in  the  formation 
of  sugar  in  the  liver  takes  place.  The  pancreas,  according  to  them, 
regulates  the  formation  of  sugar  in  the  liver  by  means  of  two  nerve- 
centres,  a  retarding  and  an  irritating  centre.  The  pancreas  irritates 
the  retarding  centre  and  retards  the  irritating  centre  of  the  liver, 
and  it  has  a  double  action  on  retarding  the  sugar  production.  The 
extirpation  of  the  pancreas  removes  the  irritation  of  the  retarding 
centres,  the  activity  of  the  irritating  centres  is  thereby  raised,  and 
in  consequence  a  strong  hyperglyc^emia  takes  place.  In  considera- 
tion of  the  above-mentioned  action  of  transj^lauted  pieces  of  pan- 
creas, we  must  accept  in  these  cases  that  the  irritating  action  on  the 
questionable  centres  under  normal  conditions  is  exercised  by  some 
other  unknown  internal  secretory  products  of  the  gland. 

Tiie  ordinary  view  in  regard  to  the  origin  of  diabetes  is,  how- 
ever, as  above  (Chapter  VIII)  stated,  that  we  have  not  to  do  with 
an  increased  production  of  sugar,  but  more  likely  a  decreased  trans- 

'  See  Centralbl.  f.  Physiol.,  Bd.  7,  S    217 
''  See  Minkowski,  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  81. 
»Mem.   Soc.   Biol.,    1893,  p.  29.     Cited  from  Centralbl.  f.  Physiol,  Bd.  7, 
S.  317. 


294  DIGESTION. 

formation  of  the  sagar  in  tlie  animal  body.  We  must  also  admit 
that  the  pancreas  has  the  ability,  in  some  way  or  other,  of  regulat- 
ing the  consumption  of  sugar;  but  we  do  not  know  how  it  acts. 
Lepine  '  has  made  an  experiment  to  explain  this  action.  Accord- 
ing to  him  a  glycolysis  regularly  takes  place  in  the  blood  (see' 
Chapter  VI),  and  the  enzyme  active  in  this  change  is  secreted  from 
the  pancreas  to  the  blood.  On  the  extirpation  of  the  pancreas 
naturally  this  function  of  the  gland  is  removed,  hence  a  hypergly- 
cemia is  produced.  Important  exceptions  have  been  made  against 
this  hypothesis  by  several  investigators,'^  and  the  action  of  the 
pancreas  in  the  elimination  of  sugar  still  stands  unexplained. 

According  to  Chauveau  and  KAUFMA]sr]sr "  a  formation  of  sugar 
takes  place  in  the  liver,  partly  from  the  glycogen  and  partly  from 
other  bodies — carbohydrates,  proteids,  and  fats — which  on  the 
destruction  of  tissues,  the  histolysis,  are  taken  up  by  the  blood  and 
carried  to  the  liver,  where  they  are  transformed  into  sugar.  The 
pancreas  has  a  preventive  action  on  the  sugar  production  of  the 
liver,  as  also  on  the  histolysis.  This  is  caused  by  means  of  an 
unknown  product  of  the  inner  secretion,  which  product  passes  into 
the  blood.  All  three  factors,  the  sugar  production  in  the  liver  as 
well  as  the  inner  secretion  of  the  pancreas  and  the  histolysis,  are, 
according  to  Kaufmann",  influenced  in  a  double  way  by  the  nervous 
system,  namely,  partly  exciting  and  partly  retarding.  The  exciting 
action  on  the  liver  and  on  histolysis  has  simultaneously  a  preventive 
action  on  the  internal  secretion  of  the  pancreas,  and  this  therefore 
causes  an  increased  formation  of  sugar  in  a  threefold  way.  The  pre- 
ventive action  on  the  liver  and  histolysis  causes  a  simultaneous  exci- 
tation of  the  internal  secretion  of  the  pancreas,  and  the  formation  of 
sugar  under  these  conditions  is  reduced  for  three  reasons.  Mar- 
cuse*  has  found  that  in  frogs,  in  which  Aldehoff  has  shown  that 
liabetes  may  be  produced  on  the  extirpation  of  the  pancreas,  no 
uiabetes  appears  on  as  perfect  extirpation  of  the  liver  as  possible. 

Pancreatic  Juice.  This  secretion  may  be  obtained  by  adjusting 
a  fistula  in  the  excretory  duct,  according  to  the  methods  suggested 
by  Beristard,''  Ludwig,^  and  Heidenhain.  '     If  the  operation  is- 

"  See  foot- note  No,  9,  p   123,  Chapter  VI. 

«  See  Minkowski,  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  31,  S.  174. 

'  Arch,  de  Physiol.,  Ser.  5,  Tome  7. 

^  Da  Bois-Reymond's  Arch.,  1894. 

*  Le9ons  de  Pbysiologie,  Tome  2,  p.  190. 

*  See  Bernstein,  Arbeiten  a.  d   physiol.  Anstalt  zu  Leipzig,  1869,  S.  1. 
■J  Pfluger's  Arch.,  Bd.  10,  S.  604. 


PANCREATIC  JUICE.  295 

performed  with  sufficient  raj^idity  and  dexterity  on  an  animal  wiiich 
has  been  well  fed  a  few  hours  before,  there  is  obtained  from  the 
fistula,  as  a  rule,  immediately  after  the  operation  {temporary  fistula) 
a  secretion  rich  in  solids,  viscid,  very  active,  and  which  may  be 
considered  as  normal  pancreatic  juice.  Ordinarily,  however,  the 
gland  becomes  diseased  in  a  few  hours  or  days  after  the  operation, 
and  the  secretion  which  then  flows  out  of  the  fistula  {permanent 
fistula)  is  more  liquid,  deficient  in  solids,  and  in  certain  other 
respects  different  from  the  secretion  obtained  immediately  after  the 
operation.  Still  a  permanent  fistula  may  also  sometimes  yield  a 
normal  secretion  for  a  long  time  (Heidenhain),  while  the  tem- 
porary fistula  in  careless  operations  may  give  no  secretion  or  only  an 
abnormal  juice. 

In  herbivora,  such  as  rabbits,  whose  digestion  is  uninterrapted, 
the  secretion  of  the  pancreatic  juice  is  continuous.  In  carnivora  it 
seems,  on  the  contrary,  to  be  intermittent  and  dependent  on  the 
digestion.  During  starvation  the  secretion  almost  stojDS,  but  com- 
mences again  after  partaking  of  food.  Food  seems  to  act  in  a 
twofold  manner.  First,  it  may,  with  the  more  abundant  flow  of 
blood  during  the  digestion,  which  is  seen  by  the  red  color  of  the 
gland,  convey  a  larger  quantity  of  nutritive  material  to  the  gland, 
and  thereby  cause  the  secretion  of  a  juice  rich  in  solid  nutritive 
bodies.  In  another  way  the  food  may  also,  by  the  irritation  which 
it  produces  on  the  mucous  coat  of  the  stomach  and  the  duodenum, 
cause  an  increased  secretion.  That  the  food  indeed  acts  in  these 
two  ways  follows  from  the  fact  that  other  substances,  such  as  ether, 
may  reflexily  act  on  the  mucous  membrane  of  the  stomach  or 
intestine,  causing  a  secretion  of  pancreatic  juice,  but  in  starvation  a 
thin  fluid  is  secreted,  and  after  partaking  of  food  a  thick  fluid  is 
produced.  According  to  the  observations  of  Bernstein",  Heiden- 
HAIN,  and  others,  the  secretion  increases  rapidly  after  eating,  and  it 
reaches  its  maximum  in  the  course  of  the  flrst  three  hours.  From 
this  time  the  secretion  diminishes,  but  may  again  increase  from  the 
oth-7tli  hour,  when  generally  large  quantities  of  food  pass  from  the 
stomach  to  the  intestine.  Then  it  again  decreases  continuously 
from  the  9th-llth  hour,  and  stops  entirely  at  the  15th-16th  hour. 
In  regard  to  the  action  of  various  bodies  on  the  secretion  Becker  ' 
has  found  that  the  introduction  of  1-2  gm.  sodium  chloride  or 
bicarbonate  diminishes  the  quantity  of  juice  secreted  by  dogs  and 

'  Arch,  des  Sciences  biol.  de  St.  Petersbourg,  Tome  2,  No.  3,  p.  433. 


296  DIGESTION. 

decreases  the  proteolytic  action  of  the  same,  while  the  introduction 
of  distilled  water  or,  still  more,  carbonated  water  increases  the 
secretion.  Pilocarpin,  according  to  Gottlieb,'  increases  the  secre- 
tion in  rabbits.  Accoiding  to  the  same  investigator  the  introduc- 
tion of  irritants  such  as  mustard-oil,  acids,  and  alkalies  into  the 
duodenum  causes  reflexly  an  increased  secretion. 

The  statements  as  to  the  amount  of  jDancreatic  juice  secreted  in 
the  course  of  24  hours  are  variable  and  not  trustworthy.  It  seems 
positively  proved  that  the  permanent  fistula  yields  a  considerably 
larger  quantity  of  secretion  than  the  temporary.  While  Kefee- 
STEiisr  and  Hallwachs,  and  Schmidt  and  Krogee,  find  that  the 
quantity  of  juice  secreted  from  the  first  is  45-100  grms.  per  kilo 
during:  24  hours.  Bidder  and  Schmidt  and  Bidder  and  Skre- 
BITZKT  claim  that  the  quantity  from  the  temporary  fistula  is  2.5-5 
grms.  per  kilo  in  the  same  time.^ 

In  regard  to  the  constituents  and  composition  of  the  pancreatic 
juice,  a  distinction  must  be  made  between  the  secretion  of  a  tem- 
porary and  of  a  permanent  fistula.  The  secretion  flowing  from  the 
former  is  in  dogs  a  clear,  colorless,  nearly  sirupy,  odorless  fluid  of 
an  alkaline  reaction  which  is  very  rich  in  proteid,  and  sometimes 
containing  so  large  a  quantity  that  it  coagulates  like  white  of  egg 
when  heated.  Besides  proteids  the  juice  contains  also  three 
enzymes — one  diastatic,  one  fat -splitting,  and  one  which  dissolves 
proteids.  The  last-mentioned  has  been  called  trypsin  by  Kuhne. 
Besides  the  above-mentioned  bodies  the  pancreatic  juice  habitually 
contains  small  quantities  of  leucin,  fat,  and  soaps.  As  mineral  con- 
stituents it  contains  chiefly  alkali  chlorides,  also  alkali  carbonates, 
and  some  phosphoric  acid,  lime,  magnesia,  and  iron. 

The  secretion  from  the  permanent  fistula  always  contains  less 
solids,  especially  proteid  and  enzymes,  than  that  from  a  temporary 
fistula.  A  long  time  after  the  operation  it  is  more  fiuid,  more 
strongly  alkaline,  and  the  property  which  the  juice  from  the  tem- 
porary fistula  has  of  dissolving  proteids  is  often  absent,  or  the  secre- 
tion shows  it  in  only  a  slight  degree.  As  an  example  of  the 
different  composition  of  the  juice  from  a  temporary  and  from  a 
permanent  fistula  we  give  below  the  analysis  of  0.  Schmidt.'  The 
figures  represent  parts  per  1000. 

1  Arch,  f .  exp.  Path.  u.  Pharm. ,  Bd.  33. 
*  Cited  from  Kuhne's  Lelirbucli.,  S.  114. 

»  Cited  from  Maly,  Chemie  der  Verdauungssafte  in  Hermann's  Handbuch, 
Bd.  5,  Theil  2,  S.  189. 


AMTLOPSIN.  297 

Juice  from  a  Temporary  Juice  from  a  Permanent 

Fistula.  Fistula. 

Water 900.8  884.4  976'8  979.9  984.6 

Solids 99.2  115.6  23.3  20.1  15.4 

Organic  substance 90.4            16.4  12.4  9.2 

Ash 8.8            6.8  7.5  6.1 

The  mineral  constituents  of  the  secretion  from  the  temporary  fistula  con- 
sisted chiefly  of  NaCl,  7.4  p.  m. 

In  the  pancreatic  juice  of  rabbits  11-36  p.  m.  solids  have  been  found,  and 
in  that  from  sheep  14.3-86.9  p.  m.  In  the  pancreatic  juice  of  the  horse  9-15.5 
p.  m.  solids  have  been  found  ;  in  that  of  the  pigeon,  13-14  p.  m. 

The  human  pancreatic  juice  has  been  analyzed  by  Hkrter  '  in  a  case  of 
stoppage  of  the  exit  of  the  juice  by  the  pressure  of  a  cancer.  This  juice, 
which  could  hardly  be  considered  as  normal,  was  clear,  alkaline,  without  odor, 
and  contained  the  three  enzymes.  It  contained  peptone,  but  no  other  proteid. 
The  quantity  of  solids  was  34.1  p.  m.  Of  these  6.4  p.  m.  were  soluble  in  alco- 
hol. It  contained  11.5  p.  m.  jjeptone  (and  enzymes)  and  6.3  p.  m.  mineral 
substances. 

Zawadsky '^  has  analyzed  the  pancreatic  juice  of  a  young  woman  with  a 
fistula,  and  found  864.05  p.  m.  water,  133.51  p.  m.  organic  and  3.44  p.  m.  in- 
organic substances.     The  quantity  of  protein  bodies  was  93.05  p.  m. 

Among  the  constituents  of  the  pancreatic  juice,  the  three 
enzymes  are  the  most  important. 

Amylopsin  or  pancreatic  diastase,  whicli  according  to  Koro- 
wiN  ^  and  ZwEiFEL^  is  not  found  in  new-born  infants  and  does  not 
appear  until  more  than  one  month  after  birth,  seems,  although  not 
identical  with  ptyalin,  to  be  nearly  related  to  it.  Amylopsin  acts 
very  energetically  upon  boiled  starch,  especially  at  -)-  37°  to  40°  C, 
and  forms,  similar  to  the  action  of  saliva,  besides  dextrin,  chiefly 
isomaltose  and  maltose,  with  only  very  little  dextrose  (Musculus 
and  V.  Mering,'  Kulz  and  Vogel'),  The  dextrose  is  probably 
formed  by  the  action  of  the  invertin  °  existing  in  the  gland  and 
juice. 

If  the  natural  pancreatic  juice  is  not  to  be  obtained,  then  the 
gland,  best  after  it  has  been  exposed  a  certain  time  (24  hours)  to 
the  air,  may  be  treated  with  water  or  glycerin.  This  infusion  or 
the  glycerin  extract  diluted  with  water  (when  a  glycerin  has  been 
used  which  has  no  reducing  action)  may  be  tested  directly  with 
starch-paste.     It  is  safer,  however,  to  first  precipitate  the  enzyme 

'  Zeitschr.  f.  physiol.  Chem.,  Bd.  4. 

5  Centralbl.  f.  Physiol.,  Bd.  5,  1891,  S.  179. 

3  See  Maly's  Jahresber.,  Bd.  3. 

•*  Untersuchungen  iiber  den  Verdauungsapparat  der  Neugeborenen.  Berlin, 
1874. 

*  Zeitschr.  f.  physiol.  Chem.,  Bd.  2. 

^  See  Tebb,  Journal  of  Physiol.,  Vol.  15,  and  Abelous,  C.  R.  Soc.  de  biol., 
1891. 


298  BIGESTION. 

from  the  glycerin  extract  by  alcohol,  and  wash  with  this  liquid,  dry 
the  precipitate  over  sulphuric  acid,  and  extract  with  water.  The 
enzyme  is  dissolved  by  the  water.  The  detection  of  sugar  may  be 
made  in  the  same  manner  as  in  the  saliva. 

Steapsin  or  Fat-splitting  Enzyme.  The  action  of  the  pancreatic 
juice  on  fats  is  twofold.  First,  the  neutral  fats  are  split  into  fatty 
acids  and  glycerin,  which  is  an  enzymotic  process;  and  secondly,  it 
has  also  the  property  of  emulsifying  the  fats. 

The  action  of  the  pancreatic  juice  in  splitting  the  fats  may  be 
shown  in  the  following  way.  Shake  olive-oil  with  caustic  soda  and 
ether,  siphon  off  the  ether  and  filter  if  necessary,  then  shake  the 
ether  repeatedly  with  water  and  evaporate  at  a  gentle  heat.  In  this 
way  we  obtain  a  residue  of  fat  free  from  fatty  acids  which  is 
neutral,  and  which  dissolves  in  acid-free  alcohol  and  is  not  colored 
red  by  alkanet  tincture.  If  such  fat  is  mixed  with  perfectly  fresh 
alkaline  pancreatic  juice  or  with  a  freshly  prepared  infusion  of  the 
fresh  gland  and  treated  with  a  little  alkali  or  with  a  faintly  alkaline 
glycerin  extract  of  the  fresh  gland  (9  parts  glycerin  and  1  part  l<fo 
soda  solution  for  each  gramme  of  the  gland),  and  some  litmus 
tincture  added  and  the  mixture  warmed  to  +  37°  C,  the  alkaline 
reaction  will  gradually  disappear  and  an  acid  one  take  its  place. 
This  acid  reaction  depends  upon  the  conversion  of  the  neutral  fats 
by  the  enzyme  into  glycerin  and  free  fatty  acids. 

The  splitting  of  the  neutral  fats  may  also  be  shown  more  exactly 
by  the  following  method.  The  mixture  of  neutral  fats  (absolutely 
free  from  fatty  acids)  and  pancreatic  juice  or  pancreas  infusion  is 
digested  at  the  temperature  of  the  body  and  treated  with  some  soda 
and  repeatedly  shaken  with  fresh  quantities  of  ether  until  all  the 
unsplit  neutral  fats  are  removed.  Then  it  is  made  acid  with  sul- 
phuric acid,  after  which  shake  the  acid  liquid  with  ether,  evaporate 
the  ether,  and  test  the  residue  for  fatty  acids. 

Another  simple  process  for  the  demonstration  of  the  fat-splitting 
action  of  the  pancreas  glands  is  the  following  (Cl.  Beenard)  :  A 
small  portion  of  the  perfectly  fresh,  finely  divided  gland  substance 
is  first  soaked  in  alcohol  (of  90^).  Then  the  alcohol  is  removed  as 
far  as  possible  by  pressing  between  blotting-paper,  after  which  the 
pieces  of  gland  are  covered  with  an  ethereal  solution  of  neutral 
butter-fat  (which  may  be  obtained  by  shaking  milk  with  caustic 
soda  and  ether).  After  the  evaporation  of  the  ether  the  pieces  of 
gland  covered  with  butter-fat  are  pressed  between  two  watcli-glasses 
and  then  gently  heated  to  37°  to  40°  C.  in  this  position.  After  a 
certain  time  a  marked  odor  of  butyric  acid  appears. 

The  action  of  the  pancreatic  juice  in  splitting  fats  is  a  process 
analogous  to  that  of  saponification,  the  neutral  fats  being  decom- 
posed, by  the  addition  of  the  elements  of  water,  into  fatty  acids  and 


TRTPSIK  299 

glycerin  according  to  the  following  formula:  C^H^.Oj.R,  (neutral 
fat)  +  311,0  =  C,H,.03.n,  (glycerin)  +  3(11.0. R)  (fatty  acid). 
This  depends  upon  a  hydrolytic  splitting,  which  was  first  positively 
proved  by  Beejstard  '  and  Berthelot."  The  pancreas-enzyme  also 
decomposes  other  esters  just  as  it  does  the  neutral  fats  (Nencki,' 
Baas  *).  The  pancreas-enzyme  which  decomposes  fats  has  been 
less  studied  than  the  other  pancreas-enzymes,  and  it  has  indeed 
been  questioned  whether  or  not  the  decomjjosition  of  the  neutral 
fats  in  the  intestine  may  not  be  effected  through  lower  organisms. 
According  to  the  investigations  of  Nencki,  it  seems  that  the  pan- 
creas actually  contains  an  enzyme  which  decomposes  fats.  This 
enzyme,  which  is  still  little  known,  appears  to  be  very  sensitive  to 
acids,  and  it  is  often  absent  in  acid  glands  not  perfectly  fresh.  If 
a  watery  infusion  of  the  gland  prepared  cold  be  treated  with  cal- 
cined magnesia,  then  the  enzyme  in  question  will,  according  to 
D anile wsKi,^  be  retained  by  the  magnesia  precipitate. 

The  fatty  acids  which  are  split  off  by  the  action  of  the  pan- 
creatic juice  combine  in  the  intestine  with  the  alkalies,  forming 
soaps  which  have  a  strong  emulsifying  action  on  the  fats,  and  thus 
the  pancreatic  juice  becomes  of  great  importance  in  the  emulsifica- 
tion  and  the  absorption  of  the  fats. 

Trypsin.  The  action  of  the  pancreatic  juice  in  digesting  2)ro- 
teids  was  first  observed  by  Bernard,  but  first  proved  by  Corvi- 
SART."  It  depends  upon  a  special  enzyme  called  by  Kuhne  trypsin. 
Strictly  speaking,  this  enzyme  does  not  occur  in  the  gland  itself. 
In  the  gland,  more  probably,  a  zymogen  occurs  from  which  the 
enzyme  is  split  off  or  formed  during  secretion,  also  by  the  action  of 
water,  acids,  alcohol,  and  other  substances.  According  to  Alber- 
TONi,'  this  zymogen  is  found  in  the  gland  in  the  last  third  of  the 
intra-uterine  life. 

The  purest  trypsin  thus  far  prepared,  isolated  by  KunisTE,'  is 
soluble  in  water,  but  insoluble  in  alcohol  or  glycerin.     The  less  pure 

'  Ann.  de  cliim.  et  physique  (3  ser.),  Tome  25. 

2  Jabresber.  d.  Cbeni..  1855.  S.  733. 

3  Arcb.  f.  exp.  Patb.  u.  Pbarm.,  Bd.  20. 

*  Zeitsclir.  f.  pbysiol.  Cbem.,  Bd.  14,  S.  416. 

*  Vircbow's  Arcb. ,  Bd.  25. 

*  Gaz.  hebdomadaire,  1857,  Nos.  15,  16,  19.  Cited  from  Bunge,  Lebrbucb. 
S.  174. 

'  See  Maly's  Jabresber.,  Bd.  8,  S.  254. 

»  Verb.  d.  naturb.-med.  Vereins  zu  Heidelberg,  (N.  F.)  Bd.  1,  Heft  3. 


300  DIGESTION. 

enzyme,  on  tlie  contrary,  is  soluble  in  glycerin.  If  the  solution  of 
the  enzyme  in  water  is  heated  to  the  boiling-point  with  the  addition 
of  a  little  acid,  it  decomposes  into  coagulated  proteid  and  peptone 
(KuH>fE).  According  to  the  investigations  of  BiERifACKi  ^  trypsin 
in  0.25-0.5^  soda  solution  is  destroyed  in  5  minutes  by  heating 
to  50°  C.  It  is  destroyed  by  heating  its  neutral  solution  to  45°  C. 
The  presence  of  albumoses  or  certain  ammonium  salts  in  alkaline 
trypsin  solutions  have  a  protective  action  to  a  certain  extent: 
Trypsin  is  destroyed  by  gastric  juice.  Like  other  enzymes,  trj^psin 
is  characterized  by  its  physiological  action.  This  action  consist  in 
dissolving  proteids  and  especially  fibrin  in  alkaline,  neutral,  or  even 
faintly  acid  solutions  with  readiness. 

The  preparation  of  pure  trypsin  has  been  tried  by  various 
experimenters.  The  purest  seems  to  have  been  prepared  according 
to  the  rather  complicated  method  of  Kuhs'E.'^  In  studying  the 
action  of  trypsin  a  less  pure  preparation  may  often  answer,  and 
various  methods  of  preparing  such  have  been  proposed,  but  we 
cannot  describe  all  of  them.  For  the  production  of  a  glycerin 
extract  (HEiDENHAiisr  ^)  the  gland  should  be  rubbed  with  glass 
jjowder  or  pure  quartz-sand,  this  mass  carefully  mixed  with  acetic 
acid  of  Ifo  (1  c.  c.  to  each  grm.  of  gland),  then  for  each  part  of  the 
gland-mass  add  10  parts  of  glycerin,  and  filter  after  about  three 
days.  By  precipitating  the  glycerin  extract  with  alcohol  and  redis- 
solving  the  j)recipitate  in  water,  we  obtain  a  solution  which  has  a 
powerful  digestive  action.  A  watery  infusion  of  the  gland  may  be 
made  only  after  it  has  been  exposed  to  the  air  for  24  hours,  and 
5-10  parts  of  water  for  each  part  by  weight  of  the  gland  should  be 
used.  According  to  Kuhxe^  the  impure  trypsin  is  allowed  to 
undergo  autodigestion  in  a  0.2^  soda  solution  and  in  the  j)i'esence 
of  thymol.  After  the  conversion  of  the  albumoses  into  j^eptones  the 
trypsin  may  be  precipitated  by  ammonium  sulphate.  An  active 
but  impure  infusion  may  be  obtained  by  digesting  the  finely  divided 
gland  for  a  few  days  with  water  containing  5-10  c.  c.  chloroform 
per  liter  (Salkowski  '). 

A  very  active  trypsin  may  be  prepared  by  extracting  the  finely 
divided  gland  of  oxen,  free  from  water  and  blood,  with  water  con- 
taining 0.01-0.05^  ^Hj.  The  filtered  extract  gives  a  precipitate 
with  acetic  acid  which  has  great  digestive  powers  and  which  can  be 
further  purified.     (Not  published  investigations  of  the  author.) 

1  Zeitschr.  f.  Biologie,  Bd.  28. 

»  Verb.  d.  naturli.-med.  Vereins  zu  Heidelberg,  (N.  F.)  Bd.  1,  Heft  3. 

3  Pfluger's  Arch.,  Bd.  10. 

*Centralbl.  f.  d.  med.  Wissenscb.,  1886,  S.  629. 

«  Deutscb.  med.  Wocbenscbr.,  1888,  No.  16. 


ACTION  OF  TRYPSIN.  301 

The  action  of  trypsin  on  j)roteids  is  best  demonstrated  by  the 
use  of  fibrin.  Ver}'  considerable  quantities  of  this  albnminons  body 
are  dissolved  by  a  small  amount  of  trypsin  at  3T— 10°  C.  It  is 
always  necessary  to  make  a  control  test  with  fibrin  alone,  with  or 
without  the  addition  of  alkali.  Fibrin  is  dissolved  by  trypsin  with- 
out any  putrefaction;  the  liquid  has  a  pleasant  odor  somewhat  like 
bouillon.  To  completely  exclude  j)utrefaction  a  little  thymol, 
chloroform,  or  ether  should  be  added  to  the  liquid.  Trypsin  diges- 
tion differs  essentially  from  pepsin  digestion  in  that  the  first  takes 
place  in  neutral  or  alkaline  reaction  and  not,  as  is  necessary  for 
pei5sin  digestion,  in  an  acidity  of  1-2  p.  m.  HCl,  and  further  by 
the  fact  that  the  proteids  dissolve  in  trypsin  digestion  without 
previously  swelling  up. 

Many  circumstances  exert  a  marked  influence  on  the  rapidity  of 
the  trypsin  digestion.  With  an  increase  in  the  quantity  of  enzyme 
present  the  digestion  is  hastened  at  least  to  a  certain  point,  and  the 
same  is  also  true  of  an  increase  in  temperature  at  least  to  about 
-f-  -10°  C,  at  which  temperature  the  proteid  is  very  rapidly  dissolved 
by  the  trypsin.  The  reaction  is  also  of  the  greatest  importance. 
Tryj)sin  acts  energetically  in  neutral,  or  still  better  in  alkaline,  solu- 
tions, and  best  in  an  alkalinity  of  3-4  p.  m.  Na^COj.  Free  mineral 
acids,  even  in  very  small  quantities,  completely  prevent  the  diges- 
tion. If  the  acid  is  not  actually  free,  but  combined  with  albumi- 
nous bodies,  then  the  digestion  may  take  place  quickly  when  the 
acid  combination  is  not  in  too  great  excess  (Chittenden  and 
Cummins').  Organic  acids  act  less  disturbingly,  and  in  the  pres- 
ence of  0.2  p.  m.  lactic  acid  and  the  simultaneous  presence  of  bile 
and  common  salt  the  digestion  may  indeed  proceed  more  quickly 
than  in  a  faintly  alkaline  liquid  (Lindberger^).  Carbon  dioxide, 
according  to  Schierbeck,*  has  a  retarding  action  in  acid  solutions, 
but  it  accelerates  the  tryptic  digestion  in  faintly  alkaline  liquids. 
Foreign  bodies,  such  as  borax  aud  potassium  cyanide,  may  promote 
tryptic  digestion,  while  other  bodies,  such  as  salts  of  mercury,  iron, 
and  others  (Chittenden  and  Cummins),  or  salicylic  acid  in  large 
quantities,  may  have  a  preventive  action.  The  nature  of  the  pro- 
teids is  also  of  importance.     Unboiled  fibrin  is,  relatively  to  most 

'  Studies  from  the  Physiol.  Chem.  Laboratory  of  Yale  College,  New  Haven, 
1885,  Vol.  I,  p.  100. 

»  See  Maly's  Jahresber.,  Bd.  13,  S.  280. 
•  Skan.  Arch.  f.  Physiol.,  Bd.  3. 


302  DIGESTION. 

other  albuminous  bodies,  dissolved  so  very  quickly  that  the  diges- 
tion test  with  raw  fibrin  gives  an  incorrect  idea  of  the  power  of 
trypsin  to  dissolve  coagulated  albuminous  bodies  in  general.  An 
accumulation  of  products  of  digestion  tends  to  hinder  the  trypsin 
digestion. 

The  Products  of  the  Trypsin  Digestion.  In  the  digestion  of 
unboiled  fibrin  a  globulin  which  coagulates  at  -j-  55-60°  C.  may  be 
obtained  as  an  intermediate  product  (Hereman^N ').  Moreover 
from  fibrin,  as  well  as  from  other  albuminous  bodies,  emanate 
albumoses  and  peptones.,  leiicin,  tyrosin,  and  aspartic  acid,  a  little 
lysin,  lysatinin  (Hedix°),  and  ammonia  (Hirschler'''),  and  also 
the  so-called  protein  chromogen^  or  tryptophan,""  a  substance  whose 
nature  is  not  known,  but  which  gives  a  reddish-violet  product,  so- 
called  proteinochrom,  with  chlorine  or  bromine.  When  putrefaction 
has  not  been  entirely  prevented  numerous  other  bodies  appear  which 
will  be  spokeu  of  later  in  connection  with  the  putrefaction  process 
going  on  ia  the  intestine.  In  the  trypsin  digestion,  in  contrast  to  the 
pepsin  digestion,  ^u.vq  peptones,  not  precipitated  by  ammonium 
sulphate,  are  relatively  easily  and  quickly  formed.  The  peptone, 
according  to  Kuhne,  consists  entirely  of  antipeptone,  and  the  above- 
mentioned  decomposition  products,  leucin  and  the  others,  are 
formed  by  the  decomposition  of  the  hemipeptone.  We  will  now 
consider  the  decomposition  products,  leucin  and  tyrosin,  formed  in 
the  trypsin  digestion  of  proteids. 

Leucin,  OgHj^NO,,  or  amido-caproic  acid,  more  recently 
called  -ar-amido-isobutylacetic  acid,  (CH3),CH.CH2.CH(NHJ. 
COOH."  Leucin  is  formed  not  only  in  the  trypsin  digestion  of 
proteids,  but  also  from  the  protein  substances  by  their  decomposi- 
tion on  boiling  with  diluted  acids  or  alkalies,  by  fusing  with  alkali 
hydrates,  and  by  putrefaction.  Because  of  the  ease  with  which 
leucin  and  tyrosin  are  formed  in  the  decomposition  of  protein  sub- 
stances, it  is  diflELcult  to  positively  decide  whether  these  bodies  when 
found  in  the  tissues  are  constituents  of  the  living  body  or  are  only 
to  be  considered  as  decomposition  products  formed  after  death. 

1  Zeitschr.  f.  pliysiol.  Chem.,  Bd.  11. 

*  See  Drechsel,  Du  Bois-Reymond's  Arch.,  1891. 
3  Zeitschr.  f.  physiol.  Chem.,  Bd.  10,  S.  302. 

^  Stadelmanii,  Zeitschr.  f.  Biologie,  Bd.  26. 
5  Neuuieister,  ibid.,  Bd.  26,  S.  329. 

*  See  Schulze  and  Likiernik,  Zeitschr.  f.  physiol.  Chem.,  Bd.  17,  and 
Gmelin,  ibid.,  Bd.  18. 


LEU  cm.  303 

Leacin  lias  been  foand  in  the  pancreas  and  its  secretion,  in  the 
spleen,  thymus,  and  lymj)h-glands,  in  the  thyroid  gland,  in  the 
salivary  glands,  in  the  kidneys,  brain,  and  liver  (but  mostly  in  dis- 
ease). It  also  occurs  in  the  wool  of  sheep,  in  dirt  from  the  skin 
(inactive  epidermis)  and  between  the  toes,  and  its  decomposition 
products  have  the  disagreeable  odor  of  the  perspiration  of  the  feet. 
It  is  found  pathologically  in  atheromatous  cysts,  ichthyosis  scales, 
pus,  blood,  and  nrine  (in  diseases  of  the  liver).  Leucin  also  occurs 
in  the  vegetable  kingdom. 

Leucin  has  been  prepared  synthetically  by  Hufner  '  from 
isovaleraldehyde-ammonia  and  hydrocyanic  acid.  This  leucin  is 
optically  inactive.  Inactive  leucin  may  also  be  prepared,  as  shown 
by  E.  ScHULZE,  Bakbieki  and  Bosshard,"  by  the  cleavage  of  pro- 
teids  with  baryta  at  160°  C.  or  on  heating  ordinary  leucin  with 
baryta-water  to  the  same  temperature.  The  Itevorotatory  modi- 
fication may  be  formed  from  the  inactive  leucin  by  the  action 
of  penicillum  glaucum.  The  leucin  obtained  in  the  pancreatic 
digestion  of  proteids  as  well  as  in  their  cleavage  with  hydrochloric 
acid,  seems  always  to  be  the  dextrorotatory  variety."  ConN*  has, 
however,  obtained  a  leucin  differing  from  the  ordinary  leucin  in 
the  tryptic  digestion  of  fibrin.  Hufner  has  prepared  an  isomer  of 
leucin  from  monobromcaproic  acid  and  ammonia.  It  is  a  question 
whether  there  exist  natural  leucins  corresponding  to  normal  caproic 
acid.  On  oxidation  the  leucins  yield  the  corresponding  oxyacids 
(leucinic  acids).  The  leucins  are  decomposed  on  heating,  evolving 
carbon  dioxide,  ammonia,  and  amylamin.  On  heating  with  alkalies, 
as  also  in  putrefaction,  it  yields  valerianic  acid  and  ammonia. 

Leucin  crystallizes  when  pure  in  shining,  white,  very  thin 
plates,  usually  forming  round  knobs  or  balls,  either  appearing  like 
hyalin  or  alternating  light  or  dark  concentric  layers  which  consist 
of  radial  groups  of  crystals.  Leucin  as  obtained  from  the  animal 
fluids  and  tissues  is  very  easily  soluble  in  water  and  rather  easily  in 
alcohol.  Pure  leucin  is  soluble  with  difficulty;  according  to  certain 
statements  it  dissolves  in  about  29  parts  of  water  at  ordinary  tem- 
peratures or  little  higher,  and  according  to  others  in  46  parts.     This 

'  Journ.  f.  prakt.  Cliem.,  N.  F.,  Bd.  1. 
'  Zeitschr.  f .  playsiol.  Chem. ,  Bdd.  9  and  10. 

3  In  regard  to  contradictory  statements  see  Hoppe-Seyler's  Handbuch,  6. 
Aufl.,  p.  134. 

*  Zeitschr.  f.  physiol.  Chem.,  Bd.  20. 


304  DIOMSTIOm 

difEereiice  may  be  due,  according  to  Gmelin/  to  the  fact  tliat  the 
optically  active  leucin  may  be  variable  mixtures  of  the  dextro-  and 
Isevorotatory  modifications.  The  inactive  leucin  is  the  most  insolu- 
ble. The  specific  rotation  of  the  ordinary  leucin,  dissolved  in 
hydrochloric  acid,  is  {a)D  =  +17.5.  Leucin  is. readily  soluble  in 
alkalies  and  acids.  On  slowly  heating  to  170°  C.  it  melts  and 
sublimes  in  white,  woolly  flakes  which  are  similar  to  sublimed  zinc 
oxide.     A  marked  odor  of  amylamin  is  generated  at  the  same  time. 

The  solution  of  leucin  in  water  is  not,  as  a  rule,  precipitated  by 
metallic  salts.  The  boiling-hot  solution  may,  however,  be  precipi- 
tated by  a  boiling-hot  solution  of  copper  acetate.  If  the  solution 
of  leucin  is  boiled  witli  sugar  of  lead  and  then  ammonia  be  added 
to  the  cooled  solution,  shining  crystalline  leaves  of  leucin-lead  oxide 
separate.  When  boiled  with  leucin,  copper  oxyhydrate  is  dissolved 
without  reduction. 

Leucin  is  recognized  by  the  appearance  of  the  balls  or  knobs 
under  the  microscope,  by  its  action  when  heated  (sublimation  test), 
and  by  Scherer's  test.  This  last  consists  in  the  leacin  yielding 
a  colorless  residue  when  carefully  evaporated  with  nitric  acid  on 
platinum-foil,  and  this  residue  when  warmed  with  a  few  drops  of 
caustic  soda  gives  a  color  varying  from  a  pale  yellow  to  brown 
(depending  on  the  purity  of  the  leucin),  and  on  further  concentrat- 
ing over  the  flame  it  agglomerates  into  an  oily  drop  which  rolls 
about  on  the  foil. 

Tyrosin,  C^Hj^J^Og,  or  ^-oxtphekyl-amidopropionic  acid, 
H0.C^H,.C,H3(NHJ.C00H,  is  derived  from  most  protein  sub- 
stances (not  gelatin)  under  the  same  conditions  as  leucin,  which  it 
habitually  accompanies.  It  is  especially  found  with  leucin  in  large 
quantities  in  old  cheese  (Tvpos),  from  which  it  derives  its  name. 
Tyrosin  has  not  with  certainty  been  found  in  perfectly  fresh  organs, 
with  the  exception,  perhaps,  of  the  spleen  and  pancreas  of  cattle. 
It  occurs  in  the  intestine  in  the  digestion  of  albuminous  substances, 
and  it  has  about  the  same  physiological  and  pathological  importance 
as  leucin. 

Tyrosin  was  prepared  by  Erlenmeter  and  Lipp'  from  p- 
amido-phenylalanin  by  the  action  of  nitrous  acid.  On  fusing  with 
caustic  alkali  it  yields  p-oxybenzoic  acid,  acetic  acid,  and  ammonia. 

'  Zeitscbr.  f.  pbysiol.  Cliem.,  Bd.  18. 

'  Ber.  d.  deutscli.  cliem.  Gesellsch.  zu  Berlin,  Bd.  15,  S.  1544. 


TTROSIN.  305 

By  putrefaction  it  may  yield  p-hydrocouniaric  acid,  oxyphenyl- 
acetic  acid,  and  p-cresol. 

Tyrosin  in  a  very  impure  state  may  be  in  the  form  of  balls 
similar  to  leuoin.  The  purified  tyrosin,  on  the  contrary,  apjjears 
as  colorless,  silky,  fine  needles  which  are  often  grouped  into  tufts 
or  balls.  It  is  soluble  with  difficulty  in  water,  being  dissolved  by 
2454:  parts  water  at  +  20°  C.  and  154  parts  boiling  water,  separat- 
ing, however,  as  tufts  of  needles  on  cooling.  It  dissolves  more 
easily  in  the  presence  of  alkalies,  ammonia,  or  a  mineral  acid.  It  is 
difficultly  soluble  in  acetic  acid.  Crystals  of  tyrosin  separate  from 
an  ammoniacal  solution  on  the  spontaneous  evaporation  of  the 
ammonia.  The  solution  of  the  tyrosin  obtained  from  protein  sub- 
stances by  the  action  of  acids  has  always  a  faint  Irevorotatory 
power.  Tyrosin  prepared  synthetically  or  by  decomposition  of 
proteids  by  baryta  is  optically  inacti\e.'  Tyrosin  is  not  soluble  in 
alcohol  or  ether.  It  is  identified  by  its  crystalline  form  and  by  the 
following  reactions: 

Piria's  7'est.  Tyrosinis  dissolved  in  concentrated  sulphuric  acid 
by  the  aid  of  heat,  by  which  tyrosin-sulj^huric  acid  is  formed;  it 
is  allowed  to  cool,  diluted  with  water,  neutralized  by  BaCOg,  and 
filtered.  On  the  addition  of  a  solution  of  ferric  chloride  the 
filtrate  gives  a  beautiful  violet  color.  This  reaction  is  disturbed  by 
the  presence  of  free  mineral  acids  and  by  the  addition  of  too  mncli 
ferric  chloride. 

Hofman"n's  Test.  If  some  water  is  poured  on  a  small  quantity 
of  tyrosin  in  a  test-tube  and  a  few  drops  of  Millox's  reagent  added 
and  then  the  mixture  boiled  for  some  time,  the  liquid  becomes  a 
beautiful  red  and  then  yields  a  red  precipitate.  Mercuric  nitrate 
may  first.be  added,  then,  after  this  has  boiled,  nitric  acid  contain- 
ing some  nitrous  acid. 

Scherer's  Test.  If  tyrosin  is  carefully  evaporated  to  dryness 
with  nitric  acid  on  platinum-foil,  a  beautiful  yellow  residue  (nitro- 
tyrosin  nitrate)  is  obtained,  which  gives  a  deep  reddish-yellow  color 
with  caustic  soda.  This  test  is  not  characteristic,  as  other  bodies 
give  a  similar  reaction. 

Leucin  and  tyrosin  may  be  prepared  in  large  quantities  by  boil- 
ing albuminous  bodies  or  albuminoids  with  dilute  mineral  acids.- 
Ordinarily  we  boil  hoof-shavings  (2  parts)  with  dilute  sulphuric  acid 

1  See  Mauthner,  Wien.  Sitzungsber.,   Bd.   85,  and  E.   Scbulze,  Zeitschr.  f. 

physiol    Chem.,  Bd.  9, 


306  DIGESTION. 

(5  parts  concentrated  acid  and  13  parts  water)  for  24  hours.  After 
boiling  the  solution  it  is  diluted  with  water  and  neutralized  while 
still  warm  with  milk  of  lime  and  then  filtered.  The  calcium  sul- 
phate is  repeatedly  boiled  with  water,  and  the  several  filtrates  are 
united  and  concentrated.  The  lime  is  precipitated  from  the  con- 
centrated liquid  by  oxalic  a^cid  and  the  precipitate  filtered  off, 
repeatedly  boiled  with  water,  all  filtrates  united  and  evaporated  to 
crystallization.  What  first  crystallizes  consists  chiefly  of  tyrosin 
with  only  a  little  leucin.  By  concentration  a  new  crystallization 
may  be  produced  in  the  mother-liquor,  which  consists  of  leucin 
with  some  tyrosin.  To  separate  leucin  and  tyrosin  from  each  other 
their  different  solubilities  in  water  may  be  taken  advantage  of  in 
preparing  them  on  a  large  scale,  but  surer'  and  better  results  are 
•obtained  by  the  following  method  of  Hlasiwetz  and  HABERiiAisrisr.^ 
The  crystalline  mass  is  boiled  with  a  large  quantity  of  water  and 
enough  ammonia  to  dissolve  it.  To  this  boiling-hot  solution  enough 
basic  lead  acetate  is  added  until  the  precipitate  formed  is  nearly 
wiiite;  now  filter,  heat  the  light  yellow  filtrate  to  boiling,  neutralize 
with  sulphuric  acid,  and  filter  while  boiling  hot.  After  cooling, 
nearly  all  the  tyrosin  is  precipitated,  while  the  leucin  remains  in  the 
solution.  The  tyrosin  may  be  purified  by  recrystallizing  from  boil- 
ing water  or  from  ammoniacal  water.  The  above-mentioned 
mother-liquor  rich  in  leucin  is  treated  with  H^S,  the  filtrate  con- 
ceiitrated  and  boiled  with  an  excess  of  freshly  precipitated  copper 
oxyhydrate.  A  part  of  the  leucin  is  precipitated,  and  the  residue 
Temains  in  the  solution  and  partly  crystallizes  as  a  cuprous  com- 
pound on  cooling.  The  copper  is  removed  from  the  precipitate  and 
solution  by  means  of  H^S,  the  filtrate  decolorized  when  necessary 
with  animal  charcoal,  strongly  concentrated  and  allowed  to  crystal- 
lize. The  leucin  obtained  from  the  precipitate  is  quite  pure,  while 
that  from  the  solution  is  somewhat  contaminated. 

If  one  is  working  with  small  quantities,  the  crystals,  which  con- 
sist of  a  mixture  of  the  two  bodies,  may  be  dissolved  in  water  and 
this  solution  precipitated  with  basic  lead  acetate.  The  filtrate  is 
treated  with  H^S,  the  new  filtrate  evaporated  to  dryness,  and  the 
residue  treated  with  warm  alcohol  which  dissolves  the  leucin  but 
not  the  tyrosin.  The  remaining  tyrosin  is  purified  by  recrystalliza- 
tion  from  ammoniacal  alcohol,  Leucin  may  be  purified  by  recrys- 
tallization  from  boiling  alcohol  or  by  precipitating  it  as  leucin  lead 
oxide,  treating  the  precipitate  suspended  in  water  with  H^S  and 
evaporating  the  filtered  solution  to  crystallization. 

To  detect  the  presence  of  leucin  and  tyrosin  in  animal  fluids  or 
tissues  the  albumin  must  first  be  removed  by  coagulation  with  the 
addition  of  acetic  acid  and  then  precipitated  by  basic  lead  acetate. 
The  filtrate  is  treated  with  H^S,  this  filtrate  evaporated  to  a  sirup 
or  to  dryness,  and  the  two  bodies  in  the  residue  are  separated  from 
each  other  by  boiling  alcohol  and  then  purified  as  above  stated. 

'  Annal.  d.  Chem.  u.  Pharin.,  Bd.  169,  S.  160. 


ASPARTIC  ACID.  307 

Aspartic  Acid,  OJI,NO^,  or  amido-succinic  acid,  CJl3(XII,J. 
(COOH)^.  This  acid  is  obtained  in  the  trypsin  digestion  of  fibrin 
and  gelatin.  It  may  also  be  obtained  by  the  decomposition  of 
albuminous  bodies  or  albuminoids  with  acids  (see  Chapter  II).  It 
lias  also  been  found  in  beet-root  molasses,  and  lastly  it  is  very  widely 
diffused  in  the  vegetable  kingdom  as  the  amid  asparagine  (aniido- 
succinic-acid  amid),  which  seems  to  be  of  the  greatest  importance 
in  the  development  and  formation  of  the  albuminous  bodies. 

Aspartic  acid  dissolves  in  256  parts  water  at  +  10°  C.  and  in 
18.6  parts  boiling  water,  and  crystallizes  on  cooling  as  rhombic 
prisms.  The  acid  prepared  from  protein  substances  is  optically 
active,  and  is  dextrogyrate  in  a  solution  strongly  acid  with  nitric 
acid,  and  laevogyrate  in  a  watery  solution.  It  forms  with  copper 
oxide  a  crystalline  combination  which  is  soluble  in  boiling-hot  water 
and  nearly  insoluble  in  cold  water,  and  whicli  may  be  used  in  the 
preparation  of  the  pure  acid  from  a  mixture  with  other  bodies.  In 
regard  to  methods  of  preparation  see  Hlasiwetz  and  Haber- 
MANN  '  and  E.  Schulze.^ 

The  action  of  trypsin  on  other  bodies  has  not  been  thoroughly 
studied.  An  enzyme  has  been  found  in  the  pancreas  of  the  pig  and 
certain  herbivora,  whicli  is  not  identical  witli  trypsin  and  which 
causes,  the  coagulation  of  neutral  or  alkaline  milk  (KiiiiNE  and 
Egberts').  Gelatin  is  dissolved  by  the  pancreatic  juice  and  is 
converted  into  gelatin-peptone.  According  to  Kuhxe  and  Ewald  * 
neither  glycocoll  nor  leucin  is  formed.  The  gelatin-forming  sub- 
stance of  the  connective  tissues  is  not  directly  dissolved  by  trypsin, 
but  only  after  it  has  been  treated  with  acids  or  soaked  in  water  at 
+  70°  C. 

By  the  action  of  trypsin  on  hyalin  cartilage  the  cells  dissolve, 
leaving  the  nucleus.  The  basis  is  softened  and  shows  an  indis- 
tinctly constructed  network  of  collagenous  substance  (Kuhne  and 
Ewald).  The  elastic  substance,  the  structureless  niemt)ra7ie,  and 
the  membrane  of  the  fat-cells  are  also  dissolved.  Parenchymatous 
organs,  such  as  the  liver  and  the  muscles,  are  dissolved  all  but  the 
nucleus,  connective  tissue,    fat-corpuscles,  and  the  remainder  of 

'L.  c. 

"  Zeitsclir.  f.  physiol.  Chem.,  Bd.  9. 

^  See  Maly's  Jabresber.,  Bd.  9,  S.  224;  also  Sidney  Edkins,  Journal  of 
Physiology,  Vol.  13,  wbicb  contains  all  tbe  literature. 

*  Verb.  d.  naturb.-med.  Vereins  zu  Heidelberg,  (N.  F.)  Bd.  1. 


308  DIGESTION. 

the  nervous  tissue.  If  the  muscles  are  boiled,  then  the  connec- 
tive tissue  is  also  dissolved.  Mucin  and  certain  nucleins  are  dis- 
solved and  split  by  trypsin  solutions.  The  digestibility  of  casein 
pseadonuclein  in  trypsin  solutions  has  been  shown  recently  by 
SEBELEi]sr.'  Popoff"  had  previously  shown  the  same  for  the 
nuclein  from  the  thymus.  Gumlich  '  and  Weii^ttraud  ^  have 
shown  that  the  nucleins  are  only  partly  utilized  in  the  intestine. 

Trypsin  seems  to  be  without  action  on  cliitin  and  horny  sub- 
stance. OxyhmmogloMn  is  decomposed  by  trypsin  with  the  splitting 
off  of  hasmatin.  HcBmoglohin,  on  the  contrary,  when  the  access  of 
oxygen  is  completely  prevented,  is  not  decomposed  by  trypsin 
(Hoppe-Setler  ^) .     Trypsin  does  not  act  on  fats  or  carbohydrates. 

It  has  already  been  brought  out  above  that  trypsin  does  not 
exist  ready  formed  in  the  gland,  but  more  likely,  as  HEiDEisrHAiN"  * 
has  shown,  the  gland  contains  a  corresponding  zymogen.  The 
maximum  quantity  of  such  zymogen  in  the  gland  occurs  14-16-18- 
hours  after  an  abundant  meal,  and  the  minimum  6-10  hours  after. 
This  zymogen  is  not  converted  by  glycerin  into  trypsin,  but  is  easily 
changed  by  water  and  acids.  A  soda  solution  of  1-1.5^,_  on  the 
contrary,  prevents  almost  entirely  the  conversion  of  the  zymogen. 
If  we  allow  the  gland  to  lie  in  the  air  it  gradually  becomes  acid,  and 
this  leads  to  the  formation  of  an  enzyme  in  which  the  oxygen  seems 
to  be  active,  as  is  usual  in  the  conversion  of  the  zymogen  into 
trypsin.  It  is  very  probable  also  that  the  two  other  enzymes  are 
formed  from  corresponding  zymogens,  and  this  has  been  shown  by 
Liversidge'  to  be  plausible  in  the  case  of  the  diastatic  enzyme. 

After  a  plentiful  meal  HEiDEisrHAiN  found  in  dogs  in  the  first 
stages  of  digestion,  when  the  secretion  of  ]3ancreatic  juice  was  most 
active,  that  the  glandular  cells  became  smaller  owing  to  the  con- 
sumption of  the  inner  granular  zone,  while  the  outer  zone  at  the 
same  time  took  up  new  material  and  became  larger.  In  these  stages 
the  quantity  of  zymogen  is  smallest.  At  a  later  period,  12-20  hours 
after  a  meal,  the  inner  zone  is  re-formed  from  the  outer,  and  the 
larger  this  zone  is  the  larger  the  quantity  of  zymogen  in  the  gland 

1  Zeitschr.  f.  pliysiol.  Chem.,  Bd.  20. 

"^  Ibid.,  Bd.  18. 

^  lUd  ,  Bd.  18. 

■*  Verbandl.  d.  physiol.  Gesellscli.  zu  Berlin,  1895. 

5  Physiol.  Chem.,  S.  267. 

«  Pfluger's  Arch.,  Bd.  10. 

''  Journal  of  Physiol.,  Vol.  8. 


CHEMICAL   PROCESSES  IX  THE  IXTESTIXE.  309 

seems  to  be.  The  zymogen  consequently  belongs  to  the  inner  zone, 
and  the  secretion  consists  therefore,  at  least  in  part,  in  a  destruction 
or  dissolution  of  this  zone  whereby  tlie  substance  of  the  gland  itself 
is  changed  into  the  secretion  (IIeidexhaix).  This  view,  however, 
is  in  opposition  to  that  of  Lewaschew,'  who  observed  that  in 
animals  which  have  starved  and  whose  pancreas  are  nearly  free 
from  zymogen,  the  inner  granular  zone  is  just  as  much  developed 
as  under  normal  conditions  and  containing  abundant  quantities 
of  zymogen.  We  are  still  completely  in  the  dark  regarding  the 
nature  of  the  chemical  processes  which  take  place  in  the  conversion 
of  the  zymogen  into  the  enzyme. 

V.  The  Chemical  Processes  in  the  Intestine. 

The  action  which  belongs  to  each  digestive  secretion  may  be 
essentially  changed  by  mixing  with  other  digestive  fluids;  and  since 
the  digestive  fluids  which  flow  into  the  intestine  are  mixed  with 
still  another  fluid,  the  bile,  it  will  be  readily  understood  that  the 
combined  action  of  all  these  fluids  in  the  intestine  makes  the  chemi- 
cal processes  going  on  therein  very  complicated. 

As  the  acid  of  the  gastric  juice  acts  destructively  on  ptyalin, 
this  enzyme  has  no  further  diastatic  action,  even  after  the  acid  of 
the  gastric  juice  has  been  neutralized  in  the  intestine.  The  bile 
has,  at  least  in  certain  animals,  a  faint  diastatic  action  which  in 
itself  can  hardly  be  of  any  great  importance,  but  which  shows  that 
the  bile  has  not  a  preventive  but  rather  a  beneficial  influence  on  the 
.energetic  diastatic  action  of  the  pancreatic  juice.  MA.RTi:sr  and 
Williams  "  have  observed  a  beneficial  action  of  the  bile  on  the 
■diastatic  action  of  the  pancreas  infusion.  To  this  may  be  added 
■that  the  organized  ferments  which  occur  habitually  in  the  intestine 
and  sometimes  in  the  food  have  j)artly  a  diastatic  action  and  j^artly 
produces  a  lactic-acid  and  butyric-acid  fermentation.  The  maltose 
which  is  formed  from  the  starch  seems  to  be  converted  into  glucose 
in  the  intestine.  Cane-sugar  is  inverted  in  the  intestine,  but, 
according  to  the  observations  of  Yoit  and  Lusk,"  milk-sugar  is  not 
inverted  in  the  intestine  of  rabbits.  Cellulose,  especially  the  finer 
and  more  tender,  is  undoubtedly  partly  dissolved  in  the  intestine; 

1  Pfliiger's  Arcb.,  Bd.  37. 

'  Proceed,  of  Eoy.  Soc,  Vols.  45  and  48. 

3  Zeitscbr.  f.  Biologie,  Bd.  28,  S.  275. 


310  DIGESTION. 

the  products  formed  hereby  are  not  very  well  known.  It  has  beea 
shown  by  Tappenier  that  cellulose  may  undergo  fermentation,, 
caused  by  the  action  of  micro-organisms  with  the  production  of 
marsh-gas,  acetic  acid,  and  butyric  acid;  still  y/e  do  not  know  to 
what  extent  the  cellulose  is  destroyed  in  this  way.' 

Bile  possesses  the  jDOwer  of  dissolving  fats  in  so  slight  a  degree 
that  it  is  scarcely  worthy  of  mention.  It  is,  however,  without 
doubt  of  greater  importance  that  the  bile,  as  IN'en'CKI  ^  and  Each- 
EOED  ^  have  shown,  facilitates  the  fat-splitting  action  of  the  pan- 
creatic juice.  This  splitting  of  the  fats  into  fatty  acids  and  glycerin 
is  an  important  factor  in  the  absorption  of  the  fats.  The  fatty  acids 
combine  with  the  alkalies  of  the  intestinal  and  pancreatic  juices, 
producing  soaps  which  are  partly  absorbed  as  snch  and  partly  exer- 
cise a  powerful  action  on  the  absorption  of  the  fats.  There  is  no 
doubt  that  the  chief  part  of  the  fats  in  the  food  is  absorbed  as  a 
fine  emulsion,  and  the  soaps  are  of  great  importance  in  the  forma- 
tion of  this  emulsion. 

If  to  a  soda  solution  of  about  2  p.  m.  Na,^C03  we  add  pure, 
perfectly  neutral  olive-oil  in  not  too  large  quantity,  we  obtain,  after 
vigorous  shaking,  a  transient  emulsion.  If,  on  the  contrary,  we 
add  to  the  same  quantity  of  soda  solution  an  equal  amount  of  com- 
mercial olive-oil  (which  always  contains  free  fatty  acids),  we  need 
only  turn  the  vessel  over  for  the  two  liquids  to  mix  and  immediately 
we  have  a  very  finely  divided  and  permanent  emulsion  making  the 
liquid  appear  like  milk.  The  free  fatty  acids  of  the  always  some- 
what rancid  commercial  oil  combine  with  the  alkali  to  form  soaps 
which  act  to  emulsify  the  fats  (Brucke,*  Gad  ^).  This  emulsifying . 
action  of  the  fatty  acids  split  off  by  the  pancreatic  juice  is 
undoubtedly  assisted  by  the  habitual  ocpurrence  of  free  fatty  acids 
in  the  food,  and  also  by  the  splitting  off  of  fatty  acids  from  the 
neutral  fats  by  the  putrefaction  in  the  intestine.  These  fatty  acids 
must  combine  with  the  alkalies  in  the  intestine  and  form  soaps. 

1  On  the  digestion  of  cellulose  see  Henneberg  and  Stohmann,  Zeitschr.  f. 
Biologie,  Bd.  21,  S.  613  ;  v.  Knieriem,  ibid.,  S.  67;  Hofmeister,  Arch.  f. 
%viss.  u.  prakt.  Thierheilkunde,  Bd.  11;  Weiske,  Zeitschr.  f.  Biologie,  Bd.  23, 
S.  37o  ;  Tappeiner,  ibid.,  Bdd.  20  and  24;  and  Mall^vre,  Pfiiiger's  Arch.,, 
Bd.  49. 

2  Arch,  f .  exp.  Path.  u.  Pharm. ,  Bd.  20. 
^  Journal  of  Physiol.,  Vol.  12. 
♦Wien.  Sitzangsber.,  Bd.  61,  Abth.  2. 

.  *Du  Bois-Reymond's  Arch.,  1878 


CHEMICAL  PROCESSES  IN  THE  INTESTINE.  311 

This  emulsification  of  fats  by  means  of  the  action  of  tlie  pan- 
creatic juice  or  by  soaps  formed  in  other  ways  can  only  take  place 
in  an  alkaline  solution.  In  the  contents  of  the  intestine,  as  long- 
as  they  are  acid,  such  an  emulsion  can  hardly  occur.  On  the  con- 
trary, it  undoubtedly  occurs  at  the  point  where  the  fat  comes  in 
contact  with  an  alkaline  secretion  under  a  mucous  membrane,  or  in 
general  where  it  meets  with  sufficient  alkali  to  form  an  emulsion. 
In  the  acid  contents  of  the  intestine  of  dogs,  wiiich  had  been  kept 
on  food  rich  in  fat,  Ludwig  and  Cash  '  observed  no  emulsion. 
After  tying  the  two  pancreas  excretory  ducts  they  found  a  remark- 
ably fine  emulsion  iu  the  chylous  vessels,  though  the  fat  in  the 
contents  of  the  intestine  was  not  emulsified.  In  this  case  it  is 
possible  that  the  free  fatty  acid  whicli  is  hardly  ever  absent  in  the 
fat  of  the  food,  and  which  may  be  produced  also  by  putrefaction  in 
the  intestine,  forms  soaps  with  the  alkali  of  the  mucous  coat  of  the 
intestine  and  produces  the  emulsion  in  the  chylous  vessels.  It  must 
not  be  forgotten  that,  according  to  many  observations,  an  emulsion 
of  the  fats  may  be  produced  by  means  of  proteid,  independently 
of  the  reaction.  In  this  regard  reference  should  be  made  to  the 
statement  of  Kuhne'  that  the  pancreatic  juice  from  a  permanent 
fistula  which  is  poor  in  proteid  has  the  emulsification  property  to 
a  less  degree  than  the  juice  from  a  temporary  fistula  which  is  rich 
in  proteid.  Kuhne  has  also  shown  that  this  emulsification 
property  is  not  to  be  ascribed  to  the  alkali,  as  faintly  acid  juices 
also  have  this  property. 

Claude  Bernard  found  long  ago  in  his  experiments  on 
rabbits,  in  which  animals  the  choledochus  duct  was  inosculated  to 
the  small  intestine  above  the  pancreas  passages,  that  when 'their 
food  contained  a  large  proportion  of  fat  the  chylous  vessels  of  the 
intestine  above  the  pancreas  passages  were  transparent,  but  below 
the  same  they  were  milky-wliite,  and  from  this  concluded  that  the 
bile  alone,  without  the  pancreatic  juice,  does  not  emiilsify  fats. 
Dastre  '  tried  the  reverse  experiment  in  dogs,  namely,  tying  the 
choledochus  duct  and  producing  a  biliary  fistula,  through  which  the 
bile  would  flow  into  the  intestine  below  the  mouth  of  the  j)ancreatic 
passages.  When  the  animals  were  killed  after  a  meal  rich  in  fat, 
the  chylous  vessels  were  first  milky-white  below  the  opening  of  the 

1  Du  Bois-Reymond's  Arcli.,  1880. 

«  LehFbuch  d.  pliysiol.  Chem.,  1868,  S.  138. 

5  Arcli.  de  pliysiol.,  (5)  Tome  2,  p.  315. 


312  BIGEtiTION. 

biliary  fistula,  Dastre  draws  the  following  conclnsion  from  this: 
that  combined  action  of  the  bile  aud  the  pancreatic  juice  is  neces- 
sary for  the  absorption  of  the  fats — a  deduction  which  coincides 
with  the  above-mentioned  observations  of  ISTEisrcKi  and  Rachford. 
The  importance  of  the  bile  and  the  pancreatic  juice  for  the  absorp- 
tion of  fats  will  be  discussed  in  detail  later  (see  Absorption) . 

Bile  completely  prevents  pepsin  digestion  in  artificial  digestion, 
and  it  may  also  retard  the  swelling  up  of  the  proteids.  The 
passage  of  bile  into  the  stomach  during  digestion,  on  the  contrary, 
seems  according  to  several  investigators,  especially  Oddi  '  and 
Dastre,^  to  have  no  retarding  action  on  stomachic  digestion.  Bile 
has  no  solvent  action  on  proteids  in  neutral  or  alkaline  reaction,  but 
still  it  may  have  an  influence  on  proteid  digestion  in  the  intestine. 
The  acid  contents  of  the  stomach,  containing  an  abundance,  of 
proteids,  give  with  the  bile  a  precipitate  of  proteids  and  bile-acids. 
This  precipitate  carries  a  part  of  the  pepsin  with  it,  and  for  this 
reason,  and  also  on  account  of  the  partial  or  complete  neutralization 
of  the  acid  of  the  gastric  juice  by  the  alkali  of  the  bile  and  the 
pancreatic  juice,  the  pepsin  digestion  cannot  proceed  further  in  the 
intestine.  On  the  contrary,  the  bile  does  not  disturb  the  digestion 
of  proteids  by  the  pancreatic  juice  in  the  intestine.  The  action 
of  these  digestive  secretions,  as  above  stated,  is  not  disturbed  by 
the  bile,  especially  not  by  the  faintly  acid  reaction  due  to  organic 
acids  which  are  habitually  found  in  the  upper  parts  of  the  intestine. 
In  a  dog  killed  while  digestion  is  going  on,  the  faintly  acid,  bile- 
containing  matter  of  the  intestine  shows  regularly  a  strong  digestive 
action  on  proteids. 

The  precipitate  formed  on  the  meeting  of  the  acid  contents  of 
the  stomach  with  the  bile  easily  redissolves  in  an  excess  of  bile  and 
also  in  the  NaCl  formed  in  the  neutralization  of  the  hydrochloric 
acid  of  the  gastric  juice.  This  may  take  place  even  under  faintly 
acid  reaction.  Since  in  man  the  excretory  ducts  of  the  bile  and  the 
pancreatic  juice  open  near  one  another,  in  consequence  of  which 
the  acid  contents  of  the  stomach  are  probably  immediately  in 
great  part  neutralized  by  the  bile  as  soon  as  it  enters,  it  is  doubtful 
whether  a  precipitation  of  proteids  by  the  bile  occurs  in  the  intestine. 

Besides  the  previously  mentioned  processes  caused  by  enzymes, 
there  are  others  of  a  different  nature  going  on  in  the  intestine, 

1  Centralbl.  f.  Physiol,  1887,  S.  313. 
"L.  c. 


ClIEMiCAL   rU0CE66ES  IN  TUE  INTESTINE.  313 

namely,  the  fermeutation  aud  putrefaction  processes  caused  by 
micro-organisms.  These  are  less  intense  in  the  upper  parts  of  the 
intestine,  but  increase  in  intensity  towards  the  lower  part  of  the 
same,  and  decrease  in  the  large  intestine  because  of  tlie  absorption 
of  water.  Fermentation  but  not  putrefaction  processes  occur  in 
the  small  intestine  as  long  as  the  contents  are  strongly  acid. 
Macfadyex,  M.  Xekcki,  and  X.  Sieber  '  have  investigated  a  case 
of  human  anus  praeternaturalis,  in  which  the  fistula  occurred  at  the 
lower  end  of  the  ileum,  and  they  were  able  to  investigate  the  con- 
tents of  the  intestine  after  it  had  been  exposed  to  the  action  of  the 
mucous  membrane  of  the  entire  small  intestine.  The  mass  was 
yellow  or  yellowish  brown,  due  to  bilirubin,  had  an  acid  reaction 
which,  calculated  as  acetic  acid*,  amounted  to  1  p.  m.  The  con- 
tents were  nearly  odorless,  having  an  empyreumatic  odor  recalling 
that  of  volatile  fatty  acids,  and  only  seldom  had  a  putrid  odor  re- 
calling that  of  indol.  The  essential  acid  jiresent  was  acetic  acid, 
accompanied  with  fermentation  lactic  acid  and  jiaralactic  acid, 
volatile  fatty  acids,  succinic  acid,  and  bile  acids.  Coagulable  pro- 
teids,  peptone,  mucin,  dextrin,  dextrose,  and  alcohol  were  jiresent. 
Leucin  and  tyrosin  could  not  be  detected. 

According  to  the  above-mentioned  investigators,  the  proteids  are 
only  to  a  very  slight  extent,  if  at  all,  decomposed  by  the  microbes 
in  the  small  intestine  of  man.  The  microbes  present  in  the  small 
intestine  preferably  decompose  the  carbohydrates,  forming  ethyl 
alcohol  and  the  above-mentioned  organic  acids.  Free  hydrochloric 
acid  does  not  occur  in  the  small  intestine,  and  it  is  the  organic  acids 
that  prevent  the  putrefaction  of  the  proteids  in  the  intestine  and 
also  reduce  the  decomposition  of  the  carbohydrates. 

Further  investigations  of  Jakowsky'  lead  to  the  same  result, 
namely,  that  in  man  the  putrefaction  of  the  proteids  does  not 
take  i^lace  in  the  small  but  in  the  large  intestine.  This  putre- 
faction of  the  proteids  is  not  the  same  as  the  pancreatic  digestion, 
and  these  two  j^rocesses  are  essentially  different  because  of  the 
products  they  yield.  In  the  pancreatic  digestion  of  proteids  there 
are  formed,  as  far  as  we  know  at  present,  besides  albumoses  and 
peptones,  lysin,  lysatinin,  proteinchromogen,  amido-acids,  and  am- 
monia. In  the  putrefaction  of  the  proteids  we  have,  indeed,  the 
same  products  formed   at  the  beginning,  but  the  decomposition 

1  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  28,  S.  311. 

'  Arch,  des  sciences  biol.  de  St.  Petersbourg,  Tome  1,  1892. 


314  DIGESTION. 

proceeds  considerably  further  and  a  number  of  products  are 
developed  which  have  become  known  through  the  labors  of  numer- 
ous investigators,  NEisrcKi,  BAUMAKisr,  Briegee,  H.  and  E.  Sal- 
KOWSKi,  and  their  pupils.  The  products  which  are  formed  in  the 
putrefaction  of  proteids  are  (in  addition  to  albumoses,  peptones, 
amido-acids,  and  ammonia)  indol,  shatol,  paracresol,  plienol, 
phenyl-propionic  acid,  and  phenyl- acetic  acid,  also  p  araoxy phenyl - 
acetic  acid  and  hydroparacumaric  acid  (besides  paracresol,  pro- 
duced in  the'  putrefaction  of  ty rosin),  volatile  fatty  acids,  carbon- 
dioxide,  hydrogen,  marsh-gas,  methyhnercaptan,  and  sulphuretted 
hydrogen.  In  the  putrefaction  of  gelatin  neither  tyrosin  nor  indol 
is  formed,  while  gycocoll  is  produced. 

Among  these  products  of  decomposition  a  few  are  of  special 
interest  because  of  their  behavior  within  the  organism  and  because 
after  their  absorption  they  pass  into  the  urine.  A  few,  such  as  the 
oxyacids,  pass  unchanged  into  the  urine.  Others,  such  as  phenol, 
are  directly  transformed  into  ethereal  sulphuric  acids  by  synthesis, 
and  are  eliminated  as  such  by  the  urine ;  on  the  contrary,  others, 
such  as  indol  and  skatol,  are  only  converted  into  ethereal  sulphuric 
acids  after  oxidation  (for  details  see  Chapter  XV).  The  quantity 
of  these  bodies  in  the  urine  varies  also  with  the  extent  of  the  putre- 
factive processes  in  the  intestine;  at  least  this  is  true  for  the 
ethereal  sulphuric  acids.  Their  quantity  increases  in  the  urine 
with  a  stronger  putrefaction,  and  the  reverse  takes  place,  as 
Baumann  '  has  shown  by  experiments  on  dogs,  when  the  intestine 
has  been  disinfected  by  calomel,  namely,  they  then  disappear  from 
the  urine. 

•    Among  the  above-mentioned  putrefactive  products  in  the  intes- 
tine the  two  following,  indol  and  skatol.  must  be  carefully  discussed. 

CH 

/    X 

Indol,     C  H  N  =  C,H^  CH,    and    Skatol,    or    methtl- 

\      / 
NH 

C.OH, 
INDOL,  0  H  N  =  C,H,  CH,  are  two  bodies  which  stand 

NH 

1  Zeitschr.  f.  physiol.  Chem..  Bd.  10. 


INDOL   AND   SKATOL.  31.5 

in  close  relationship  to  tlie  indigo  substances,  and  wliicli  are  formed 
from  the  albuminous  bodies  by  their  jDutrefaction,  or  by  fusion  with 
caustic  alkali.  Hence  they  occur  habitually  in  the  human  intes- 
tinal canal  and,  after  oxidation  into  indoxyl  and  skatoxyl  respec- 
tively, pass,  at  least  partly,  into  the  urine  as  the  corresponding 
ethereal  sulphuric  acids  and  also  as  glycuronic  acids. 

These  two  bodies  have  been  jirepared  syntheticall}^  in  many 
ways.  Both  may  be  obtained  from  indigo  by  reducing  it  with  tin 
and  hydrochloric  acid  and  heating  this  reduction  product  with  zinc- 
dust  (Baeyer  ').  Indol  may  be  formed  from  skatol  by  passing  it 
through  a  red-hot  tube.  Indol  susjiended  in  water  is  in  part 
oxidized  into  indigo-blue  by  ozone  (Nexcki  "). 

Indol  and  skatol  crystallize  in  shining  leaves,  and  their  melting- 
points  are  +  52°  and  95°  C.  respectively.  Indol  has  a  peculiar 
excrementitious  odor,  while  skatol  has  an  intense  fetid  odor  (skatol 
obtained  from  indigo  should  be  odorless).  Both  bodies  are  easily 
volatilized  by  steam,  skatol  more  easily  than  indol.  They  may 
both  be  removed  from  the  watery  distillate  by  ether.  Skatol  is  the 
more  insoluble  of  the  two  in  boiling  water.  Both  are  easily  soluble 
in  alcohol,  and  give  with  jiicric  acid  a  combination  consisting  of  red 
crystalline  needles.  If  a  mixture  of  the  two  picrates  be  distilled 
with  ammonia,  they  both  pass  over  without  decomposition;  while 
if  they  are  distilled  with  caustic  soda,  the  indol  but  not  the  skatol 
is  decomposed.  The  watery  solution  of  indol  gives  with  fuming 
nitric  acid  a  red  liquid,  and  then  a  red  precipitate  of  nitroso-indol 
nitrate  (Xencki  ').  It  is  better  to  first  add  two  or  three  drops  of 
nitric  acid,  and  then  a  2^  solution  of  potassium  nitrite,  drop  by 
drop  (Salkowski^).  Skatol  does  not  give  this  reaction.  An 
alcoholic  solution  of  indol  treated  with  hydrochloric  acid  colors  a 
pine  chip  cherry-red.  Skatol  does  not  give  this  reaction.  Skatol 
dissolves  in  concentrated  hydrochloric  acid  with  a  violet  coloration. 
On  warming  skatol  with  sulphuric  acid  a  beautiful  purple-red 
coloration  is  obtained  (CiamiciAjST  and  MagxAo^ini  ^). 

For  the  detection  of  indol  and  skatol  in,  and  their  jireparation 
from,  excrement  and  j^utrefying  mixtures,  the  main  points  of  the 

1  Annal.  d.  Chem.  u.  PLarm.,  Bd.  140,  and  Supplbd.  7,  S.  56  ;  also  Ber.  d. 
deutscb.  chem.  Gesellsch. ,  Bdd.  1  and  3. 

*  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  8,  S.  727. 
3  Ibid.,  Bd.  8,  S.  723  and  1517. 

*  Zeitschr.  f.  physiol.  chem.,  Bd.  8,  S.  447. 

*  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  2!.  S.  1928. 


3 1  6  DIGESTION. 

usual  method  are  as  follows:  The  mixture  is  distilled  after  acidify- 
ing with  acetic  acid;  the  distillate  is  then  treated  with  alkali  (to 
combine  with  any  phenol  which  may  be  present)  and  again  distilled. 
From  this  second  distillate  the  two  bodies,  after  the  addition  of 
hydrochloric  acid,  are  precipitated  by  picric  acid.  The  picrate  pre- 
cipitate is  then  distilled  with  ammonia.  The  two  bodies  are 
obtained  from  the  distillate  by  repeated  shaking  with  ether  and 
evaporation  of  the  several  ethereal  extracts.  The  residue,  contain- 
ing indol  and  skatol,  is  dissolved  in  a  very  small  quantity  of  absolute 
alcohol  and  treated  with  8-10  vols,  of  water.  Skatol  is  precipi- 
tated, but  not  the  indol.  The  further  treatment  necessary  for  their 
separation  and  purification  will  be  found  in  other  works. 

The  gases  which  are  produced  by  the  decomposition  processes 
are  mixed  in  the  intestinal  tract  with  the  atmospheric  air  swallowed 
with  the  saliva,  and  as  the  gas  generated  by  ditferent  foods  varies, 
so  the  mixture  of  gases  after  various  foods  should  have  a  dissimilar 
composition.  This  is  found  to  be  true.  Oxygen  is  only  found  in 
very  faint  traces  in  the  intestine ;  this  may  be  accounted  for  in  part 
by  the  formation  of  reducing  substances  in  the  fermentation 
processes  which  combine  with  the  oxygen,  and  partly,  perhaps 
chiefly,  to  a  diffusion  of  the  oxygen  through  the  tissues  of  the  walls 
of  the  intestine.  To  show  that  these  processes  take  place  mainly  in 
the  stomach  the  reader  is  referred  to  page  278,  on  the  composition 
of  the  gases  of  the  stomach.  Nitrogen  is  habitually  found  in  the 
intestine,  and  it  is  probably  due  chiefly  to  the  swallowed  air,  or 
perhaps  in  part,  as  Bunge  '  claims,  to  a  diffusion  of  nitrogen  from 
the  tissues  of  the  intestinal  walls  to  the  intestine.  The  carbon 
dioxide  originates  partly  from  the  contents  of  the  stomach,  partly 
from  the  putrefaction  of  the  proteids,  partly  from  the  lactic-acid 
and  butyric-acid  fermentation  of  carbohydrates,  and  partly  from 
the  setting  free  of  carbon  dioxide  from  the  alkali  carbonates  of  the 
pancreatic  and  intestinal  juices  by  their  neutralization  through  the 
hydrochloric  acid  of  the  gastric  jaice  and  by  organic  acids  formed 
in  the  fermentation.  Hydrogen  occurs  in  largest  quantities  after  a 
milk  diet  and  in  smallest  quantities  after  a  purely  meat  diet.  This 
gas  seems  to  be  formed  chiefly  from  the  butyric-acid  fermentation 
of  carbohydrates,  although  it  may  occur  in  large  quantities  in  the 
putrefaction  of  'proteids  under  certain  circumstances.  There  is  no 
doubt  that  the  methylmercaptan  and  sulfhuretted  hydrogen  which 
occurs  normally  in  the  intestine  originates  from  the  proteids.     The 

'  Lelirbucli  d.  pliysiol.  u.  path.  Chem.,  1.  Aiifi.,  S.  268. 


PUTREFACTIVE  PROCES!<ES  IN    THE  INTESTINE.       817 

marsh-gas  imdonbtedly  originates  in  the  putrefaction  of  proteids. 
As  proof  of  this  Euge  '  found  26.4:5^  marsh-gas  in  the  human 
intestine  after  a  meat  diet.  He  found  a  still  greater  quantity  of 
this  gas  after  a  diet  consisting  of  leguminous  plants;  this  coincides 
with  the  observation  that  marsh-gas  may  be  produced  by  a  fermen- 
tation of  carbohydrates,  but  especially  of  cellulose  (Tappeiner"). 
Such  an  origin  of  marsh-gas,  especially  in  herbivora,  is  to  be 
expected.  A  small  part  of  the  marsh-gas  and  carbon  dioxide  may 
also  depend  on  the  decomposition  of  lecithin  (Hasebroek  ') . 

Putrefaction  in  the  intestine  not  only  depends  upon  the  com- 
position of  the  food,  but  also  upon  the  albuminous  secretions  and 
the  bile.  Among  the  constituents  of  bile  which  are  changed  or 
decomposed  we  have  not  only  the  pigments — the  bilirubin  yields 
hydrobilirubin  and  a  brown  pigment — but  also  the  bile-acids, 
especially  tanrocholic  acid.  Glycocholic  acid  is  more  stable,  and  a 
part  is  found  unchanged  in  the  excrement  of  certain  animals,  while 
tanrocholic  acid  is  so  completely  decomposed  that  it  is  entirely 
absent  in  the  fgeces.  In  the  fretus,  in  whose  intestinal  tract  no 
putrefaction  j)rt)cesses  occur,  we  find,  on  the  contrary,  undecom- 
posed  bile-acids  and  bile-j)igments  in  the  contents  of  the  intestine. 
The  reduction  of  bilirubin  into  hydrobilirubin  does  not,  according 
to  Macfadyex,  Xexcki,  and  Sieber,*  take  place  in  man  in  the 
small  but  in  the  large  intestine. 

That  the  secretions  rich  in  proteids  are  of  importance  in  jratre- 
faction  in  the  intestine  follows  from  the  fact  that  putrefaction  may 
also  continue  during  complete  fasting.  From  tlie  observations  of 
Muller  ^  on  Cetti  it  was  found  that  the  elimination  of  indican 
during  starvation  rapidlv  decreased  and  after  the  third  day  of 
starvation  it  had  entirely  disappeared,  while  the  phenol  elimination, 
which  at  first  decreased  so  that  it  was  nearly  minimum,  increased 
again  from  the  fifth  day  of  starvation  and  on  the  eighth  or  ninth 
day  it  was  three  to  seven  times  as  much  as  in  man  under  ordinary 
circumstances.  In  dogs,  on  the  contrary,  the  elimination  of  indican 
during  starvation  is  considerable,  but  the  i:)lienol  elimination  is 
minimum.     Among  the  secretions  which  undergo  putrefaction  in 

1  Wien.  Sitzungsber.,  Bd.  44. 
»L.  c. 

*  Zeitschr.  f.  physiol  Chem.,  Bd.  12. 

*  Arcli.  f.  exp.  Path.  u.  Pliarm.,  Bd.  28. 

«  Berlin,  klin.  Wochenschr. ,  1887,  No.  24. 


318  DIGESTION. 

the  intestine,  the  pancreatic  juice,  which  putrefies  most  readily, 
takes  first  place.  Pisenti  '  found,  in  liis  experiments  on  dogs,  that 
the  elimination  of  indican  hy  the  urine  greatly  diminished  after 
tying  the  pancreatic  ducts,  but  that  it  increased  again  when  the 
animal  was  giyen  pancreas  peptones  or  pancreatic  juice. 

From  the  foregoing  facts  we  conclude  that  the  products  formed 
by  the  putrefaction  in  the  intestine  are  in  part  tlie  same  as  those 
formed  in  digestion.  The  putrelaction  may  ue  o±  benefit  to  the 
organism  so  far  as  the  formation  of  such  joroducts  as  albumoses, 
peptones,  and  perhaps  also  certain  amido-acids  is  concerned.  On 
the  contrary,  the  formation  of  further  splitting  products  is  to  be 
considered  as  a  loss  of  valuable  material,  and  it  is  therefore  im- 
portant that  putrefaction  in  the  intestine  is  kept  within  certain 
limits.  If  an  animal  is  killed  while  digestion  in  the  intestine  is 
going  on,  the  contents  of  the  small  intestine  give  out  a  peculiar  but 
not  putrescent  odor.  Also  the  odor  of  the  contents  of  the  large 
intestine  is  far  less  offensive  than  a  putrefying  pancreas  infusion  or 
a  ]3utrefying  mixture  rich  in  proteid.  From  this  we  may  conclude 
that  putrefaction  in  the  intestine  is  ordinarily  not  nearly  as  intense 
as  outside  of  the  organism. 

It  seems  thus  to  be  provided,  under  physiological  conditions, 
that  putrefaction  shall  not  proceed  too  far,  and  the  factors  which 
here  come  under  consideration  are  probably  of  different  kinds. 
Absorption  is  undoubtedly  one  of  the  most  important  of  them,  and 
it  has  been  proved  by  actual  observation  that  the  |)utref action 
increases,  as  a  rule,  as  the  absorption  is  checked  and  fluid  masses 
accumulate  in  the  intestine.  The  character  of  the  food  also  has  an 
unmistakable  influence,  and  it  seems  as  if  a  large  quantity  of  carbo- 
hydrates in  the  food  acts  against  putrefaction  (Hirschlee'^). 

It  has  been  shown  by  Pohl,  BiERjiTACKi,  Rovighi,  Wik"ter- 
ITITZ,  and  ScHMiTZ  ■'  that  milk  and  kephir  have  a  specially  strong 
preventive  action  on  putrefaction.  This  action,  according  to 
ScHMiTZ,  is  not  due  to  the  casein,  but  chiefly  to  the  lactose  and  also 
in  part  to  the  lactic  acid. 

A  specially  strong  preventive  action  on  putrefaction  has  been 

1  See  Maly's  Jahresber..  Bd.  17,  S.  277. 

2  Zeitsclir.  f.  pliysiol.  Chem.,  Bd.  10,  S.  306. 

^  Ibid.,  17,  S.  401,  which  gives  references  to  the  older  literature, 
and  Bd.  19.  See  also  Salkowski,  Centralbl.,  f.  d.  med.  Wiss.,  1893, 
S.  467. 


PUTREFACTIVE  PROCESSES  IN  THE  INTESTINE.       319 

ascribed  foi*  a  loug  time  to  the  bile.  This  auti-putrid  actiou  is  not 
due  to  neutral  or  faintly  alkaline  bile,  which  itself  easily  putrefies, 
but  to  the  free  bile-acids,  especially  taurocholic  acid  (Maly  and 
Emich,'  Lindbergek'').  There  is  no  question  that  the  free  bile- 
acids  have  a  strong  preventive  action  on  putrefaction  outside  of  the 
organism,  and  it  is  therefore  difficult  to  deny  such  an  action  in  the 
intestine,  Notwithstanding  this  the  anti-putrid  action  of  the  bile 
in   the   intestine  is  contradicted   by  certain  investigators   (Voit,' 

KOHMAISTN""). 

Biliary  fistula3  have  been  established  so  as  to  study  the  import- 
ance of  the  bile  in  digestion  (Schwaxn,"  Blondlot,"  Bidder  and 
Schmidt,'  and  others).  As  a  result  it  has  been  observed  that  with 
fatty  foods  an  imperfect  absorjition  of  fat  regularly  takes  place,  and 
the  excrements  contain,  therefore,  an  excess  of  fat  and  have  a  light- 
gray  or  pale  color.  The  extent  of  deviation  from  the  normal  after 
the  operation  is  essentially  dependent  upon  the  character  of  the 
food.  If  an  animal  is  fed  on  meat  and  fat,  then  the  quantity  of 
food  must  be  considerably  increased  after  the  operation,  otherwise 
the  animal  will  become  very  thin,  and  indeed  die  with  symptoms  of 
starvation.  In  these  cases  the  excrements  have  the  odor  of  carrion, 
and  this  was  considered  a  proof  of  the  action  of  the  bile  in  checking 
putrefaction.  The  emaciation  and  the  increased  want  of  food 
depend,  naturally,  upon  the  imperfect  absorption  of  the  fats,  whose 
high  calorific  value  is  reduced  and  must  be  rejDlaced  by  the  taking 
up  of  larger  quantities  of  other  nutritive  bodies.  If  the  quantity 
of  proteids  and  fats  be  increased,  then  this  last,  which  can  be  only 
very  incompletely  absorbed,  accumulates  in  the  intestine.  This 
accumulation  of  the  fats  in  the  intestine  only  renders  the  action  of 
the  digestive  juices  on  jiroteids  more  difficult,  and  these  last  increase 
the  amount  of  putrefaction.  This  explains  the  appearance  of  fetid 
faeces,  whose  pale  color  is  not  due  to  a  lack  of  bile-pigments,  but 
to  a  surplus  of  fat  (Rohmanx,  Voit).  If  the  animal  is,  on  the 
contrary,  fed  on  meat  and  carbohydrates,  it  may  remain  quite 
normal,  and  the  leading  off  of  the  bile  does  not  cause  any  increased 

1  Monatslieft  f.  Chem.,  Bd.  4. 

*  Maly's  Jaliresber.,  Bd.  14,  S.  334. 

*  Beitr.  z.  Biologic.     Jubilaumsschrift.     Stuttgart,  1882. 

*  Pfluger's  Arch.,  Bd.  29. 

'  Miller's  Arcli.  f.  Anat.  u.  Physiol.,  1844. 

*  Essai  sur  les  fonctions  du  foie  et  de  ses  annexes.    Paris,  1846. 
■•  Die  Verdauungssafte  und  der  Stoffwechsel,  S.  98. 


320  BIOESTION. 

putrefaction.  The  carbohydrates  may  be  uniuterruptedly  absorbed 
in  sach  large  quantities  that  they  replace  the  fat  of  the  food,  and 
this  is  the  reason  why  the  animal  on  such  a  diet  does  not  become 
emaciated.  As  with  this  diet  the  putrefaction  in  the  intestine  is 
no  greater  than  under  normal  conditions  even  though  the  bile  is 
absent,  it  would  seem  that  the  bile  in  the  intestine  exercises  no  pre- 
ventive action  on  putrefaction. 

We  must  remember,  however,  that  the  presence  of  free  acids 
counteracts  putrefaction,  and  further  that  the  carbohydrates  yield 
free  acids  by  acid  fermentation  within  the  intestine.  It  is  there- 
fore conceivable  that  to  the  carbohydrates,  which,  according  to 
HiRSCHLEK,  are  capable  of  checking  putrefaction  without  entering 
into  an  acid  fermentation,  the  antiseptic  action  of  the  bile  is  due. 
It  cannot  be  denied  that  the  bile  under  ordinary  conditions,  with  a 
mixed  diet  deficient  in  carbohydrates,  has  a  preventive  action  on  the 
putrefaction  in  the  intestine.  Limboueg  '  has  shown  that  it  acts 
in  an  antiseptic  sense,  so  that  the  destruction  of  the  proteids,  giving 
rise  to  simpler  products  less  valuable,  or  perhaps  even  injnrious,  in 
the  organism,  is  checked. 

Although  the  question  how  the  putrefactive  processes  in  the 
intestine  under  physiological  conditions  are  kept  within  certain 
limits  cannot  be  answered  positively,  still  it  may  be  asserted  that 
the  acid  reaction  of  the  upper  parts  of  the  intestine  and  the  absorp- 
tion of  water  in  the  lower  parts  are  important  factors. 

That  the  acid  reaction  in  the  intestine  has  a  preventive  influence 
on  the  putrefactive  processes  follows  from  the  existing  relation 
between  the  degree  of  acidity  of  the  gastric  juice  and  the  putrefac- 
tion in  the  intestine.  After  the  investigations  and  observations  of 
Kast,  Stadelmaxis",  Wasbutzki,  Biernacki,  and  Mester  had 
j)roven  that  an  increased  putrefaction  in  the  intestine  occurred 
when  the  quantity  of  hydrochloric  acid  in  the  gastric  juice  was 
diminished  or  deficient,  Schmitz  "^  has  lately  shown  in  man  that  on 
the  administration  of  hydrochloric  acid,  producing  a  hyperacidity 
of  the  gastric  juice,  the  putrefaction  in  the  intestine  may  be 
checked. 

Excrements.  It  is  evident  that  the  residue  which  remains  after 
completed  digestion  and  absorption  in  the  intestine  must  be  differ- 
ent, both  qualitatively  and  quantitatively,   according  to  the  variety 

'  Zeitsclir.  f.  physio],  Chem.,  Bd.  13. 

'  Ibid.,  B'l.  19,  S.  401,  wliicli  includes  all  the  pertinent  literature. 


EXCREMENT.  321 

and  quantity  of  the  food.  In  man  the  quantity  of  excrement  from 
a  mixed  diet  is  120-150  grms.,  with  30-37  grms.  solids,  per  24 
hours,  while  the  quantity  from  a  vegetable  diet,  according  to  Voit,' 
was  333  grms.,  with  75  grms.  solids.  With  a  strictly  meat  diet  the 
excrements  are  scanty,  pitch-like,  and  colored  nearly  black  by 
hffimatin  and  iron  sulphide.  The  scanty  excrements  in  starvation 
have  a  similar  appearance.  A  large  quantity  of  coarse  bread  yields 
a  great  amount  of  light-colored  excrement.  If  there  is  a  large  pro- 
portion of  fat,  it  takes  a  lighter,  clayey  appearance.  The  decom- 
position products  of  the  bile-pigments  seem  to  play  only  a  small  part 
in  the  normal  color  of  the  faces. 

The  constituents  of  the  fseces  are  of  different  kinds.  We  find 
in  the  excrements  digestible  or  absorbable  constituents  of  the  food, 
such  as  muscle-fibres,  connective  tissues,  lumps  of  casein,  grains  of 
starch,  and  fat  which  have  not  had  sufiicient  time  to  be  completely 
digested  or  absorbed  in  the  intestinal  tract.  In  addition  the  excre- 
ments contain  indigestible  bodies,  such  as  remains  of  plants,  keratin 
substances,  nuclein,  and  others;  also  form-elements  originating 
from  the  mucous  coat  and  the  glands;  constituents  of  the  different 
secretions,  such  as  mucin,  cholalic  acid,  dyslysin,  and  cholesterin; 
mineral  bodies  of  the  food  and  the  secretions;  and,  lastly,  products 
of  putrefaction  or  of  the  digestion,  such  as  skatol,  indol,  volatile 
fatty  acids,  lime,  and  magnesia  soaps.  Occasionally,  also,  parasitesi 
of  different  kinds  occur;  and  lastly,  the  excrements  contain  micro- 
organisms, fungi  of  different  kinds,  sometimes  in  such  large 
quantities  that  the  chief  mass  of  the  excrements  seems  to  consist  of 
micro-organisms  (y.   Jaksch*). 

That  the  mucous  membrane  of  the  intestine  by  its  secretion 
and  by  the  abundant  quantity  of  detached  epithelium  contributes 
essentially  to  the  formation  of  excrement  follows  from  the  observa- 
tions first  made  by  L.  Hermann,'  who  separated  a  loop  of  intestine, 
washed  it  clean  and  united  the  two  ends,  forming  a  ring,  and 
restored  the  continuity  of  the  remainder  of  the  intestine.  He 
found  in  a  few  days  a  mass  resembling  fasces  which  he  called  "  ring 
faeces." 

>  Zeitschr.  f.  Biologie,  Bd.  25,  S.  264. 

»  Klinisclie  Diagnostik,  3  Aufl.  S.  302. 

'  Pflilger's  Arch.,  Bd.  46.  See  also  Ehrenthal,  t6z<?.,  Bd.  48;  Bernstein. 
ibid.,  Bd.  53;  Klecki,  Centralbl.  f.  Physiol  ,  1893,  S.  736,  and  F.  Voit,  Zeitsclir.' 
f.  Biologie,  Bd.  29. 


322  DIGESTION. 

The  reaction  of  the  excrements  is  very  changeable.  It  is  often 
•acid  in  the  inner  part,  while  the  outer  layers  in  contact  with  the 
mucous  coat  have  an  alkaline  reaction.  In  nursing  infants  it  is 
habitually  acid  (Wegscheidee  ').  The  odor  is  perhaps  chiefly  due 
to  skatol,  which  was  first  found  in  the  excrements  by  Bkiegek,  and 
so  named  by  him.  Indol  and  other  substances  also  take  part  in  the 
production  of  odor.  The  color  is  ordinarily  light  or  dark  brown, 
and  depends  above  all  upon  the  nature  of  the  food.  Medicinal 
Taodies  may  give  the  faeces  an  abnormal  color.  The  excrements  are 
colored  black  by  iron  and  bismuth,  yellow  by  rhubarb,  and  green 
by  calomel.  This  last-mentioned  color  was  formerly  accounted  for 
by  the  formation  of  a  little  mercury  sulphide,  bnt  now  it  is  said 
that  calomel  checks  the  putrefaction  and  the  decomposition  of  the 
l)ile-pigments,  so  that  a  part  of  the  bile-pigments  pass  into  the 
faeces  as  biliverdin.  According  to  Lesage  "  a  green  color  of  the 
excrements  in  children  is  caused  partly  by  biliverdin  and  partly  by 
a  pigment  produced  from  a  bacillus.  In  the  yolk-yellow  or  green- 
ish-yellow excrements  of  nursing  infants  we  can  detect  bilirubin. 
ISTeither  bilirubin  nor  biliverdin  seems  to  exist  in  the  excrements  of 
mature  persons  under  normal  conditions.  On  the  contrary,  we  find 
STBECOBILIN"  (Masius  and  Vanlaie),  which,  according  to  certain 
investigators,  is  identical  with  hydrobilirubin  (Malt),  which  is 
obtained  from  bilirubin  by  a  reduction  process,  and  urobilin 
(Jaffe) — a  view  contested  by  MAcMui^isr.'  Bilirubin  may  occur 
in  pathological  cases  in  the  faeces  of  mature  persons.  It  has  been 
observed  in  a  crystallized  state  (as  haematoidin)  in  the  faeces  of 
children  as  well  as  of  grown  persons  (Uffelmaistn',*  V.  Jaksch  *). 

The  absence  of  bile  (acholic  faeces)  causes  the  excrements  to 
have,  as  above  stated,  a  gray  color,  due  to  large  quantities  of  fat; 
this  may,  however,  be  partly  attributed  to  the  absence  of  bile-pig- 
ments. In  these  cases  a  large  quantity  of  crystals  has  been  observed 
(Gerhakdt,  v.  Jaksch)  which  consist  chiefiy  of  magnesia  soaps 
(OESTEELEisr)  or  sodium  soaps  (Stadelmajstis"^).  Hemorrhage  in 
the  upper  parts  of  the  digestive  tract  yields,  when  it  is  not  very 
abundant,  a  dark-brown  excrement,  due  to  haematin. 

1  See  Maly's  Jaliresber.,  Bd.  6,  S.  482. 
■"  Ibid.,    Bd.  18,  S.  336. 
3  See  Chapter  VIII,  on  the  bile,  p.  234. 
■1  Deutsch.  Arcli.  f.  klin.  Med.,  Bd.  24. 

*  Klinische  Diagnostik,  4.  Aufl.,  S.  373. 

•  In  regard  to  fat  crystals  in  the  faeces  see  v.  Jaksch,  1.  c,  p.  274. 


MECONIUM.  323 

ExCRETiN,  SO  named  by  Marcet,'  is  a  crystalline  body  occurring  in  human 
excrement,  but  which,  according  to  Hoppe-Seylek,  is  perhaps  only  impure 
cholesterin.  Excretolic  acid  is  the  name  given  by  Marcet  to  an  oily  body 
with  an  excrementitious  odor. 

In  consideration  of  the  very  variable  composition  of  excrements 
their  quantitative  analyses  are  of  little  value  and  therefore  will  be 
omitted. 

Meconium  is  a  dark  brownish-green,  pitchy,  mostly  acid  mass 
without  any  strong  odor.  It  contains  greenish-colored  epithelium 
cells,  cell-detritus,  numerous  fat-globules,  and  cholesterin  plates. 
The  amount  of  water  and  solids  is  respectively  720-800  and  280-200 
p.  m.  Among  the  solids  we  find  mucin,  bile-pigments  and  bile- 
acids,  cholesterin,  fats,  soaps,  calcium  and  magnesium  phosphates. 
Sugar  and  lactic  acid,  albuminous  bodies  (?)  and  peptones,  also 
lencin  and  tyrosin  and  the  other  products  of  putrefaction  occurring 
in  the  intestine,  are  absent.  Meconium  may  contain  undecomposed 
taurocholic  acid,  bilirubin  and  biliverdin,  but  it  does  not  contain 
any  hydrobilirubin,  which  is  considered  as  proof  of  the  non-exist- 
ence of  putrefactive  processes  in  the  digestive  tract  of  tbo  foetus. 

In  medico-legal  cases  it  is  sometimes  necessary  to  decide  whether 
spots  on  linen  or  other  substances  are  caused  by  meconium.  In 
such  cases  we  have  the  following  conditions:  The  spot  caused  by 
meconium  has  a  brownish-green  color  and  can  be  easily  separated 
from  the  material  because,  on  account  of  the  ropy  property  of  the 
meconium,  it  is  difficult  to  wet  through.  When  moistened  with 
water  it  does  not  develop  any  special  odor,  but  on  warming  with 
dilute  sulphuric  acid  it  has  a  somewhat  fetid  odor.  It  forms  with 
water  a  slimy,  greenish-yellow  liquid  containing  brown  flakes.  The 
solution  gives  with  an  excess  of  acetic  acid  an  insoluble  precipitate 
of  mucin;  on  boiling  it  does  not  coagulate.  The  filtered,  watery 
extract  gives  Gmelin's,  but  still  better  IIuppekt's,  reaction  for 
bile-pigments.  The  liquid  precipitated  by  an  excess  of  milk  of  lime 
gives  a  nearly  colorless  filtrate,  which  after  concentration  gives 
Pettenkofer's  reaction. 

Tlie  contents  of  the  intestine  under  abnormal  conditions  are 
perhaps  less  the  subject  of  chemical  analysis  than  of  an  inspection 
or  microscopical  investigation.  On  this  account  the  question  as  to 
the  properties  of  the  contents  of  the  intestine  in  different  diseases 
cannot  be  thoroughly  treated  here.  The  question  as  to  the  different 
processes  which,  so  far  as  they  are  dependent  on  secretion  and 
absorption,  cause  an  abnormal  consistency,  a  thinning  of  the  excre- 

*  Annal.  de  chim.  et  de  phys..  Tome  59 


324  DIGESTION. 

meats,  possesses  a  certain  interest.  Such  excrements  may  in  part 
be  produced  by  arrested  absorption  of  liquid  from  the  intestine  for 
some  reason  or  other,  and  in  part  caused  by  an  increased  secretion 
or  a  transudation  of  liquids  into  the  intestine. 

A  diminished  absorption  (of  water)  may  be  caused  by  a  more 
active  movement  of  the  intestine,  whicli  causes  their  contents  to 
pass  quickly,  and  in  this  way  the  action  of  laxatives  is  often  ex- 
plained. A  diminished  absorption  may  also  be  due  to  a  decreased 
activity  of  the  absorbing  cells.  In  absorption,  which  is  generally 
accepted  to-day,  the  cells  of  the  mucous  coat  take  an  active  part, 
and  anything  which  acts  disturbingly  on  the  protoplasm  of  these 
cells  must  also  exercise  an  influence  on  the  absorption.  This  con- 
dition with  regard  to  the  action  of  laxatives  has  been  especially 
noted  by  Hoppe-Setlee.'  According  to  him,  it  is  also  probable 
that  such  laxatives,  of  which  only  traces  are  required  for  absorp- 
tion, by  a  direct  action  on  the  intestinal  epithelium — whether  the 
absorption  is  made  more  difficult,  or  a  transudation  made  possible, 
or  whether  the  action  of  these  two  is  simultaneous — cause  watery 
evacuations.  According  to  RoHMA]srisr,^  concentrated  salt  solutions 
act  by  a  decreased  absorption  activity. 

A  thin  evacuation  may  be  produced  by  an  increased  elimination 
of  fluid  into  the  intestine,  and  there  are  many  investigators  who 
consider  it  positively  proved  that  a  transudation  of  liquid  into  the 
intestine  is  caused  by  the  action  of  saline  laxatives. 

The  character  of  the  intestinal  epithelium  is  undoubtedly  an 
important  factor  in  the  production  of  such  a  transudation,  and 
when  this  is  caused  by  the  saline  laxatives  it  probably  is  produced 
by  action  on  the  epithelium.  We  must  admit  with  Hoppe-Setler 
and  other  investigators  that  the  most  important  regulator  of  the 
flow  of  liquid  through  the  intestinal  mucous  membrane  is  the  intes- 
tinal epithelium.  It  is  the  epithelium  which  renders  possible  the 
stream  of  fluid  contrary  to  the  laws  of  osmosis,  and  which  under 
normal  conditions  prevents  a  transudation  into  the  intestine. 
Bodies  which  affect  the  epithelium  may  therefore  cause  a  transuda- 
tion, and  this  is  found  to  be  especially  abundant  after  ejection  of 
the  intestinal  epithelium.  The  most  striking  example  of  this  is 
observed  in  Asiatic  cholera,  in  which  the  epithelium  is  largely 
expelled  and  an  extraordinarily  abundant  transudation  takes  place. 

1  Physiol.  Chem.,  S.  359  and  361. 

2  Pfliiger's  Arch.,  Bd.  41. 


INTESTINAL   CONCREMENTS.  325 

Appendix. 

Intestinal  Conerements. 

Calculi  occur  very  seldom  in  human  intestine  or  in  the  intestine 
of  carnivora,  but  they  are  quite  common  in  herbivora.  Foreign 
bodies  or  undigested  residues  of  food  may,  when  for  some  reason  or 
other  they  are  retained  in  the  intestine  for  some  time,  become 
incrusted  with  salts,  especially  ammonium-magnesium  phosphate  or 
magnesium  phosphate,  and  these  salts  form  usually  the  chief  con- 
stituent of  the  conerements.  In  man  they  are  sometimes  oval  or 
round,  yellow,  yellowish  gray,  or  brownish  gray,  of  variable  size, 
consisting  of  concentric  layers  and  containing  chiefly  ammonium- 
magnesium  phosphate,  calcium  phosphate,  besides  a  small  quantity 
of  fat  or  pigment.  The  nucleus  ordinarily  consists  of  some  foreign 
body,  such  as  the  stone  of  a  fruit,  a  fragment  of  bone,  or  something 
similar.  In  those  countries  where  bread  made  from  oat-bran  is  an 
important  food,  we  often  find  in  the  large  intestine  balls  similar  to 
the  so-called  hair-balls  (see  below).  Such  calculi  contain  calcium 
and  magnesium  phosphate  (about  70^),  oat-bran  (15-18^),  soaps 
and  fat  (about  10%).  Concretions  which  contain  very  much  (about 
74^)  fat  seldom,  occur  and  those  consisting  of  fibrin  clots,  sinews, 
or  pieces  of  meat  incrusted  with  phosphates  are  also  rare. 

Intestinal  calculi  often  occur  in'animals,  especially  in  horses  fed 
on  bran.  These  calculi,  which  attain  a  very  large  size,  are  hard 
and  heavy  (as  much  as  8  kilos)  and  consist  in  great  part  of  concen- 
tric layers  of  ammonium-magnesium  phosphate.  Another  variety 
of  conerements  which  occurs  in  horses  and  cattle  consists  of  gray- 
colored,  often  very  large,  but  relatively  light  stones  which  contain 
plant  residues  and  earthy  phosphates.  Stones  of  a  third  variety 
are  sometimes  cylindrical,  sometimes  spherical,  smooth,  shining, 
brownish  on  the  surface,  consisting  of  matted  hairs  and  plant-fibres, 
and  termed  hair-balls.  The  so-called  "  ^ciagropila,"  which 
probably  originate  from  the  antilopus  rupicapea,  belong  to  this 
group,  and  are  generally  considered  as  nothing  else  than  the  hair- 
balls  of  cattle. 

The  so-called  oriental  hezoar-stone  belongs  also  to  the  intestinal 
conerements,  and  probably  originates  from  the  intestinal  tract  of 
the  CAPRA  ^GAGRUS  and  antilope  dorcas.  We  may  have  two 
varieties   of   bezoar-stones.     One   is    olive-green,   faintly    shining, 


326  DIGESTION. 

formed  of  concentric  layers.  On  heating  it  melts  with  the  develop- 
ment of  an  aromatic  odor.  It  contains  as  chief  constituent  litho- 
PELLIC  acid,  C.jHj^O^,  which  is  related  to  cholalic  acids,  and  besides 
this  a  bile-acid,  lithobilic  acid.  The  others  are  nearly  blackish 
brown  or  dark  green,  very  glossy,  consisting  of  concentric  layers, 
and  do  not  melt  on  heating.  They  contain  as  chief  constituent 
ELLAGic  ACID,  a  derivative  of  tannic  acid,  of  the  formula  Cj^H^Og, 
which  gives  a  deep  blue  color  with  an  alcoholic  solution  of  ferric 
chloride.  This  last-mentioned  bezoar-stone  originates,  to  all 
appearances,  from  the  food  of  the  animal. 

Ambergris  is  generally  considered  an  intestinal  concrement  of  the  sperm- 
whale.  Its  chief  constituent  is  ambrain,  which  is  a  non-nitrogenous  sub- 
stance perhaps  related  to  cholesterin.  Ambrain  is  insoluble  in  water  and  is 
not  changed  by  boiling  alkalies.     It  dissolves  in  alcohol,  ether,  and  oils. 

VI.  Absorption. 

The  problem  of  digestion  consists  in  part  in  separating  the 
valuable  constituents  of  the  food  from  the  useless  constituents  and 
to  dissolve  or  transform  these  first  into  forms  which  are  necessary 
in  the  processes  of  absorption.  In  discussing  the  absorption 
processes  we  must  treat  of  the  form  into  which  the  different  foods 
are  transformed  before  absorption,  of  the  manner  in  which  this  is 
accomplished,  and,  lastly,  of  the  forces  which  act  in  these  processes. 

Peptone  is  the  final  product  of  the  digestion  of  albuminous 
bodies.  Now  as  peptone  is  a  'very  soluble  and  a  relatively  easily 
diffusible  modification  of  proteids,  it  is  not  difficult  to  admit  the 
deduction  that  proteids  must  be  changed  into  peptone  in  order  that 
it  may  be  readily  absorbed.  Certain  observations  of  Funkes  '  on 
animals  confirm  this  view.  He  found  in  an  untied  intestinal  knot 
of  a  living  animal  that  the  peptone  (in  the  old  sense  of  the  word) 
was  absorbed  considerably  faster  than  other  proteids.  There  is  also 
no  doubt  that  a  part  of  the  proteids  is  invariably  absorbed  from  the 
intestinal  canal  as  peptones,  or  more  correctly  perhaps  as  albumoses 
and  peptones.  But  it  has  been  positively  settled  by  the  investiga- 
tions of  Beucke,'  Bauer  and  Voit,'  Eichhorst,*  Czeeky  and 
Latschenberger,*  that  non-peptonized  proteids,  casein,  myosin, 

'  SeeKiihne's  Lehrb.  d.  physiol.  Chem.,  S.  145. 
«  Wien.  Sitzungsber. ,  Bdd.  37  and  59. 
^  Zeitschr  f.  Biologie,  Bd.  5. 
*  Pfluger's  Arch. ,  Bd.  4. 
^  Virchow's  Arch. .  Bd.  59. 


ABSORPTION  OF  PROTEIDS.  327 

and  alkali  albuminates  are  absorbed  from  the  intestine — a  matter 
which  is  of  practical  importance  especially  with  regard  to  the 
nutritive  clysters.  If  the  proteids  can  be  absorbed  partly  as  such 
and  partly  as  peptone  or  albumoses,  then  the  question  arises,  how 
much  more  can  it  be  absorbed  in  one  form  than  in  the  other? 

This  question  cannot  be  decisively  answered.  Several  investiga- 
tions have  been  made  on  this  subject,  but  it  is  hardly  possible  to 
draw  any  positive  conclusion  from  them.  In  feeding  experiments 
on  pigs  Ellenberger  and  Hofmeister  '  found  that  meat  was  only 
slowly  digested  and  the  quantity  of  albumoses  and  jDeptones  in  the 
intestinal  canal  was  always  very  small.  Ewald  and  Gumlich  ^ 
have  obtained  the  same  results  in  regard  to  the  quantity  of  peptone 
in  normal  human  stomachs  after  partaking  of  meat.  Although  the 
albumoses  and  peptones  are  rather  readily  (perhaps  more  readily 
than  other  proteids)  absorbed,  still  it  is  clear  that  no  positive  con- 
clusion can  be  drawn  as  to  the  abundance  of  peptone-formation 
from  the  small  quantities  of  albumoses  or  jieptones  found  in  a 
certain  portion  of  the  intestine.  The  investigations  of  Schmidt- 
MuLHEiM  ^  of  the  contents  of  the  stomach  and  intestine  of  dogs 
who  were  killed  at  various  times  after  a  meal  of  boiled  meat  show 
that  the  quantity  of  peptone  in  the  intestinal  canal  is  considerably 
larger  than  the  quantity  of  simply  dissolved  proteids,  and  this  seems 
to  indicate  that  in  these  cases  the  greatest  part  of  the  jn-oteids  is 
absorbed  as  peptones  (or  albumoses). 

In  what  way  are  the  albumoses  and  peptones  absorbed,  and  how 
are  they  conveyed  to  the  tissues  ?  Ludwig  and  iSchmidt-Mul- 
HEIM  ^  tied  the  jugular  and  humeral  arteries  and  lymphatic  vessels 
of  both  sides  of  a  dog,  completely  cutting  off  the  chyle  from  the 
blood  circulation,  as  shown  later  on  dissection.  They  found  that 
the  absorption  from  the  intestine  hereby  was  not  imiaaired,  and  it  fol- 
lows from  this  that  the  proteids  do  not  reach  the  blood  through  the 
lymphatic  vessels,  but  through  the  walls  of  the  intestinal  ejjithelium. 
The  observations  of  Muistk  and  Eosensteix  ^  on  a  patient  with  a 
lymphatic  fistula  have  led  to  the  same  conception.  They  observed 
that  the  quantity  of  proteid  in  the  chyle  did  not  materially  increase 

•  Du  Bois-Reymond's  Arch. ,  1890. 

5  Berl.  klin.  Wochenscbr.,  1890,  Xo.  44. 
'  Du  Bois-Reymond's  Arch.,  1879. 
'^  Ibid.,  1877,  S.  549. 

*  Virchow's  Arcli.,  Bd.  123. 


328  DIGESTION. 

after  a  meal  rich  in  proteids.  IS  either  albumoses  nor  peptones  are 
found  in  the  chyle  after  a  meal  rich  in  proteids.  As  the  peptones 
(albumoses  included)  do  not  pass  in  to  the  lymph,  it  is  to  be  expected 
that  peptones  may  be  found  in  the  blood  during  or  after  digestion. 
This  is  not  the  case.  Schmidt-Mulheim  '  and  Hofmeister  *  only 
found  traces  of  peptone  in  the  sernni  or  blood,  and  according  to 
IS'eumeister  ^  not  even  traces  exist  in  the  blood. 

What  becomes  of  the  peptone  absorbed  from  the  intestine  ?  If 
peptone  is  introduced  into  the  circulating  blood  it  is  quickly 
eliminated  from  the  blood  by  means  of  the  urine  (Plosz  and 
Gyeegtai,"  Hoemeistbe,*  Schmidt-Mulheim  ').  The  same  takes 
place  on  the  subcutaneous  injection  of  peptone.  Normal  urine  does 
not  contain  any  peptone,  and  the  absence  of  this  body  in  the  blood 
after  digestion  cannot  be  explained  by  the  statement  that  an  elimi- 
nation of  this  peptone  takes  place  through  the  kidneys.  As  the 
peptone  introduced  in  the  blood  is  quickly  eliminated  through  tlie 
kidneys,  while  that  formed  in  the  intestine  does  not  pass  into  the 
nrine,  we  can  perhaps  consider  that  this  peptone  is  retained 
normally  by  the  liver  and  is  consumed,  and  only  that  peptone  which 
finds  its  way  into  the  circulating  blood  by  evasion  from  this  organ 
passes  into  the  urine.  This  supposition,  however,  is  untenable. 
ISTeumeister  '  has  investigated  the  portal  blood  of  rabbits  in  whose 
stomachs  large  quantities  of  albumoses  and  peptones  had  been 
introduced,  and  found  therein  only  traces  of  the  body  in  question. 
He  has  also  shown  that  when  we  supply  the  liver  of  a  dog  with  the 
]Dortal-blood  peptone  (ampho-peptone),  this  is  not  retained  by  the 
liver,  but  is  eliminated  with  the  urine.  Shore  ^  has  arrived  at 
similar  results  in  regard  to  the  importance  of  the  liver,  and  has  also 
shown  that  the  spleen  cannot  transform  peptone.  Peptone  seems 
to  pass  neither  into  the  blood  nor  the  chylous  vessels,  and  the 
following  observation  of   Ludwig   and  Salvioli"  bears  out  this 

1  Du  Bois-Reymond's  Arcli.,  1880. 
^  Zeitschr.  f .  pliysiol.  Chem. ,    Bdd.  5  and  6. 
3  Zeitschr.  f.  Biologic,  Bd.  24,  S.  272. 
*  Pflliger's  Arcli.,  Bd   10. 
5  Zeitschr.  f.  physiol.  Chem.,  Bd.  5. 
«  Da  Bois-Reymond's  Arch.,  1880. 

■"  See    Neumeister,    Sitzungsber.   d.   phys.-med.  Gesellsch.    zu   Wilrzburg, 
1889,  and  Zeitschr.  f.  Biologie,  Bd.  24. 
8  Journal  of  Physiol.,  Vol.  11. 
'  Du  Bois-Reymond's  Arch.,  1880,  Supplement. 


TRANSFORMATION  OF  ALBUMOSES  AND  PEPTONES.     329 

assumption.  These  investigators  introduced  a  i^eptone  solution 
into  a  double-ligatured,  isolated  piece  of  the  small  intestine,  which 
was  kept  alive  by  passing  defibrinated  blood  through  it  and  observed 
that  the  peptone  disappeared  from  the  intestine,  but  that  the  blood 
passing  through  did  not  contain  any  peptone. 

All  observations  indicate  that  the  albumoses  and  peptones  are 
transformed  in  some  way  in  the  intestine  or  intestinal  wall. 

Certain  investigators,  such  as  Y.  Ott,'  Nadixe  Popoff,'  and 
Julia  Brixck  '  are  of  the  opinion  that  the  albumoses  and  jieptones 
of  gastric  digestion  are  transformed  into  seralbumin  before  they 
pass  into  the  walls  of  the  digestive  tract.  This  transformation  is 
brought  about  by  means  of  the  ei^ithelium  cells,  as  also  by  the  living 
activity  of  a  fungus  called  by  Julia  Brixck  micrococcus  resti- 
tuens.     Xo  positive  proofs  have  been  presented  for  this  view. 

The  view  that  the  transformation  of  the  albumoses  and  peptones 
takes  place  after  they  have  been  taken  up  by  the  mucous  membrane 
has  better  foundation.  The  above-mentioned  experiments  of 
LuDwiG  and  Salvioli  confirm  this,  as  do  also  the  observations  of 
HoFMEiSTER  ^ — according  to  whom  the  walls  of  the  stomach  and  the 
intestine  are  the  only  parts  of  the  body  in  which  peptones  occur 
constantly  during  digestion — that  peptone  (at  the  temperature  of 
the  body)  after  a  time  disappeared  from  the  excised  but  apjiarently 
still  living  mucous  coat  of  the  stomach.  Peptone  seems  to  undergo 
a  change  in  the  mucosa  of  the  digestive  canal. 

If,  then,  peptone  already  disappears  in  the  mucous  coat,  or  at 
least  in  the  walls  of  the  digestive  tract,  the  question  naturally 
arises,  what  becomes  of  the  peptone  in  the  mucous  membrane  ? 
The  experiments  of  Maly,°  Plosz  and  Gyergyai,^  Adamkiewicz,' 
ZuxTZ,*  and  Pollitzer'  have  established  that  the  albumoses  and 
peptones  may  be  substituted  for  proteid  in  the  food,  and  may  also 
be  converted  into  ordinary  proteid.     We  must  then  assume  that 

'  Du  Bois-Reyinond's  Arcli.,  1883. 

«  Zeitschr.  f.  Biologie,  Bd.  25. 

»  Ibid. ,  Bd.  25,  S.  453. 

*  Zeitschr.  f.  pliysiol.  Chem.,  Bd.  6. 

'  Pfluger's  Arch.,  Bd.  9. 

«L.c. 

'  Die  Natur  und  der  Nahrwerth  des  Peptons.    Berlin,  1877. 

8  Pflilger's  Arch.,  Bd.  37,  S.  313. 

» Ibid.,  Bd.  37,  S.  301. 


330  BIOESTION. 

peptone  is  already  converted  into  proteid  in  the  mucous  membrane 
of  the  digestive  canal. 

According  to  Hofmeistek  '  a  considerable  increase  of  leucocytes 
occurs  in  the  adenoid  tissues  during  digestion,  an  observation  which 
is  in  close  accord  with  that  of  Pohl,"  who  found  that  in  dogs  after 
an  albuminous  diet  the  venous  blood  of  the  intestine  contains  more 
leucocytes  than  the  arterial  blood.  According  to  Hofmeistee, 
leucocytes  play  an  important  part  in  the  absorption  and  assimilation 
of  the  peptones.  They  may  take  up  the  peptones  and  be  the  means 
of  transporting  them  to  the  blood,  and  secondly  by  their  growth, 
regeneration,  and  increase  may  stand  in  close  relation  to  the  trans- 
formation and  assimilation  of  the  peptones.  HEiDENHAiisr,^  who 
considers  that  the  transformation  of  peptone  into  proteid  in  the 
mucous  membrane  is  positively  settled,  does  not  attribute  so  great 
an  importance  to  these  last  in  the  absorption  of  the  peptones  as 
HoFMEiSTER,  chiefly  on  the  ground  of  comparative  estimation  of 
the  quantity  of  absorbed  peptones  and  leucocytes.  He  considers  it 
most  probable  that  the  reconversion  of  the  peptones  into  proteid 
takes  place  in  the  epithelium  layers.  This  view  is  further  corrobo- 
rated by  the  investigations  of  Shore.* 

The  extent  of  the  proteid  absorption  is  dependent  essentially 
upon  the  kind  of  food  introduced,  since  as  a  rule  the  protein  sub- 
stances from  an  animal  source  are  much  more  completely  absorbed 
than  from  a  vegetable  source.  As  proof  of  this  we  give  the  follow- 
ing observations :  In  his  experiments  on  the  utilization  of  certain 
foods  in  the  intestinal  canal  of  man  Eubner  *  found  with  an  exclu- 
sive animal  diet  on  partaking  of  an  average  of  738-884  grms.  fried 
meat  or  948  grms.  eggs  per  day  that  the  nitrogen  deficit  with  the 
excrement  was  only  2.5-2.8^  of  the  total  introduced  nitrogen. 
With  exclusive  milk  diet  the  results  were  somewhat  unfavorable, 
since  after  partaking  of  4100  grms.  milk  the  nitrogen  deficit  rose 
indeed  to  12^.  The  conditions  are  quite  different  with  vegetable 
food,  as  shown  by  the  experiments  of  Meyer,'  Rubner,'  HuLTGREif 

'  Arcli.  f.  exp.  Path.  u.  Pliarm.,  Bdd.  19,  20,  and  33. 

^  Ibid. ,  Bd.  35. 

spfluger's  Arch.,  Bd,  43. 

*L.  c. 

5  Zeitschr.  f .  Biologie,  Bd.  15. 

« lUd.,  Bd.  7. 

■"  lUd.,  Bd.  15. 


ABSORPTION  OF  PROTEIDS.  331 

and  Landergkex/  who  made  experiments  with  various  kinds  of 
rye  bread  and  found  that  the  loss  of  nitrogen  through  the  faces 
amounted  to  22-48^.  Experiments  with  other  vegetable  foods,  and 
also  the  investigations  of  Schuster/  Cramer/  Meixert,*  Mori/ 
and  others  on  the  utilization  of  foods  with  mixed  diets,  have  led  to 
similar  results.  All  through  we  see  that  the  loss  of  nitrogen  by  the 
excrement  increases  with  an  abundant  amount  of  vegetable  food  in 
the  diet. 

The  reason  for  this  is  manifold.  The  often  large  quantity  of 
cellulose  j)resent  in  vegetable  foods  impedes  the  absorption  of  pro- 
teids.  The  stronger  irritation  produced  by  the  vegetable  food 
itself  or  by  the  organic  acids  formed  in  the  fermentation  in  the 
intestinal  canal  causes  a  stronger  peristalsis  which  drives  the  con- 
tents of  the  intestine  quicker  than  otherwise  along  the  intestinal 
canal.  Another  and  most  important  reason  is  the  fact  that  a  part 
of  the  vegetable  protein  substances  seems  to  be  indigestible. 

In  speaking  of  the  functions  of  the  stomach  we  stated  that  after 
the  removal  or  excision  of  this  organ  an  abundant  digestion  and 
absorption  of  proteids  may  take  place.  It  is  therefore  of  interest 
to  learn  how  the  digestion  and  absorption  of  proteids  go  on  after 
the  extirpation  of  the  second  proteid-digesting  organ,  the  pancreas. 
In  this  regard  Minkowski  and  Abelmank  °  found  after  the  total 
extirpation  of  the  pancreas  of  dogs  that  the  utilization  of  the  pro- 
teids was  on  an  average  44^,  and  after  partial  extirpation  5-i^. 
Sandmeyer  ''  found  in  dogs  after  the  extirpation  of  |  or  f  of  the 
gland,  and  leaving  pieces  not  in  connection  with  the  intestine,  that 
the  utilization  of  the  proteids  amounted  to  G2-70^.  All  three 
investigators  found  that  on  the  addition  of  raw  ox-pancreas  to  the 
food  the  utilization  of  the  proteids  was  essentially  increased,  and  on 
the  addition  of  sufficient  finely  chopped  pancreas  Sandmeyer 
observed  even  a  proteid  absorption  which  did  not  differ  much  from 
that  of  a  normal  dog.     It  seems  that  the  destructive  action  of  the 

•  Nord.  mfrd.  Arkiv.,  Bd.  21,  No.  8. 

'  See  Voit,  Untersuch.  der  Kost,  etc.,  S.  142. 
3  Zeitschr.  f.  pbysiol.  Cliem.,  Bd.  6. 

•  Ueber  Massenernabrung.     Berlin,  1885. 

^  Kellner  and  Mori,  Zeitscbr.  f.  Biologie,  Bd.  25. 

•  Ueber   die  Ausnutzung   der  Nabrungsstoffe  nacb  Pankreasexstirpation, 
etc.     Inaug.  Diss.     Dorpat,  1890.     Cited  from  Maly's  Jabresber.,  Bd.  20. 

Zeitscbr.  f.  Biologie,  Bd.  31. 


3S'2  DIQESTION. 

gastric  Juice  on  the  trypsin  does  not  assert  itself  under  these 
circumstances,  or  only  to  a  slight  extent. 

The  carbohydrates  are,  it  seems,  chiefly  absorbed  as  monosac- 
charides. Glucose,  lasvulose,  and  galactose  are  probably  absorbed 
as  such.  The  two  disaccharides,  cane-sugar  and  maltose,  ordinarily 
undergo  an  inversion  in  the  intestinal  tract  and  are  converted  into 
glucose  and  Isevulose.  Lactose,  according  to  Yoit  and  Lusk,^  is 
not  inverted  and  is  absorbed  as  such  except  what  undergoes  lactic- 
acid  fermentation.  The  polysaccharides  are  also  finally  converted 
into  monosaccharides,  although  in  certain  cases  an  absorption  of 
dextrin  may  take  place.  According  to  the  observations  of  Otto  ' 
and  V.  Mering  °  the  portal  blood  contains  besides  dextrose  a 
dextrin-like  carbohydrate  after  a  carbohydrate  diet.  A  part  of  the 
carbohydrates  is  destroyed  by  fermentation  in  the  intestine,  with 
the  formation  of  lactic  and  acetic  acids. 

The  different  varieties  of  sugars  are  absorbed  with  varying 
degrees  of  rapidity,  but  as  a  general  thing  they  are  absorbed  very 
qaickly.  With  experiments  on  dogs  ALBERTOivri  *  found  on  intro- 
ducing 100  grms.  of  the  sugar  that  during  the  first  hour  60  grms. 
dextrose  were  absorbed,  maltose  and  cane-sugar  70-80,  and  lactose 
only  20-40  grms.  He  fiuds  that  lactose  is  relatively  more  readily 
absorbed  from  dilute  solutions  than  from  concentrated  ones. 

On  the  introduction  of  starch  even  in  very  considerable  quanti- 
ties into  the  intestinal  tract  no  dextrose  passes  into  the  urine,  which 
probably  depends  in  this  case  upon  the  absorption  and  assimilation 
and  the  slow  saccharification  taking  place  at  the  same  pace.  If,  on 
the  contrary,  large  quantities  are  introduced  at  one  time,  then  an 
elimination  of  sugar  by  the  urine  takes  place,  and  this  elimination 
of  sugar  is  called  alimentary  glycosuria.  In  these  cases  the  assimi- 
lation of  the  sugar  and  the  absorption  do  not  take  place  at  the  same 
pace,  hence  the  liver  and  the  remaining  organs  do  not  have  the 
necessary  time  to  fix  and  utilize  the  sugar.  This  glycosuria  may 
also  in  part  be  due  to  the  fact  that  the  introduction  of  considerable 
quantities  of  sugar  forces  the  sugar  in  absorption  not  only  in  the 
ordinary  way  through  the  blood-vessels  to  the  liver  (see  below),  but 

1  Zeitschr.  f.  Biologie,  Bd.  28. 

"^  Christiania  Vidensk.  Selskabs  Porli.,  1886,  No.  11,  and  Maly's  Jahresber., 
Bd.  17. 

*  Du  Bois-Reymond's  Arch.,  1877. 

*  Manifire  de  se  comporter  des  sucres,  etc.     Arch.  ital.  de  Biol.,  Tome  15. 


ABSORPTION  OF  CARBOHYDRATES.  333 

also  in  part  by  passing  into   the  blood  circulation   through   the 
lymphatic  vessels,  evading  the  liver. 

That  quantity  of  sugar  to  which  we  must  raise  the  sugar  par- 
taken of  to  produce  an  alimentary  glycosuria  gives,  according  to 
HoFMEiSTER,'  the  assimilation  limit  for  that  same  sugar.  This 
limit  is  different  for  various  kinds  of  sugar;  and  it  also  varies  for 
the  same  sugar  not  only  in  different  animals,  but  also  for  different 
members  of  the  same  kind,  as  also  for  the  same  individual  under 
different  circumstances.  In  general  we  can  say  that  in  regard  to  the 
ordinary  varieties  of  sugar,  such  as  dextrose,  I^vulose,  cane-sugar, 
maltose,  and  lactose,  the  assimilation  limit  is  highest  for  dextrose 
and  lowest  for  lactose.  We  must  admit  that  with  an  overabundant 
quantity  of  sugars  in  the  intestinal  tract  the  disaccharides  do  not 
have  sufficient  time  for  their  complete  inversion;  hence  it  is  not 
remarkable  that  disaccharides  have  been  found  in  the  urine  in  cases 
of  alimentary  glycosuria,' 

From  the  investigations  of  Ludwig  and  v.  Mering  ^  and  others 
we  learn  in  regard  to  the  way  in  which  the  sugars  pass  into  the 
blood-stream,  namely,  that  they  as  well  as  bodies  soluble  in  water 
do  not  ordinarily  pass  over  into  the  chylous  vessels  in  measurable 
quantities,  but  are  in  greatest  part  taken  up  by  the  blood  in  the 
capillaries  of  the  villi  and  in  this  way  pass  into  the  mass  of  the 
blood.  These  investigations  have  been  confirmed  by  observations 
of  I.  MuxK  and  Rosensteix  ■*  on  human  beings. 

The  reason  why  the  sugar  and  other  soluble  bodies  do  not  pass 
over  into  the  chylous  vessels  in  appreciable  quantity  is,  according 
to  Heidexhain,^  to  be  found  in  the  anatomical  conditions,  in  the 
arrangement  of  the  capillaries  close  under  the  layer  of  epithelinm. 
Ordinarily  these  capillaries  find  the  necessary  time  for  the  taking 
up  of  the  water  and  the  solids  dissolved  in  it.  But  when  a  large 
quantity  of  liquid,  such  as  a  sugar  solution,  is  introduced  into  the 
intestine  at  once,  this  is  not  possible,  and  in  these  cases  a  part  of 
the  dissolved  bodies  passes  into  the  chylous  vessels  and  the  thoracic 
duct  (Ginsberg  °  and  Rohmanx  '). 

'  Arch.  f.  exp.  Path.  u.  Pharm.,  Bdd.  25  and  26. 

'  For  the  literature  in  regard  to  the  passage  of  various  kinds  of  sugars  into 
the  urine  see  C.  Voit,  Ueber  die  Glykogenbildung,  Zeitschr.  f.  Biologie,  Bd.  28. 

*  Du  Bois-Reymond's  Arch. ,  1877. 
«L.  c. 

*  Pfliiger's  Arch.,  Bd.  43,  Suppl. 

*  Ibid.,  Bd.  44. 
'  Ibid.,  Bd.  41. 


334  DIGESTION. 

The  introduction  of  larger  quantities  of  sugar  into  the  intestine 
at  one  time  can  readily  cause  a  disturbance  with  diarrhcsal  evacua- 
tions of  the  intestine.  If  the  carbohydrate  is  introduced  in  the 
form  of  starch,  then  very  large  quantities  may  be  absorbed  without 
causing  any  disturbance  and  the  absorption  may  be  very  com- 
plete. EuBiSTER '  found  the  following:  On  partaking  508-670 
grms.  carbohydrate  as  wheat  bread  jjer  day  the  part  not  absorbed 
amounted  to  only  0.8-2.6^.  For  peas,  where  357-588  grms.  were 
eaten,  the  loss  was  3.6-7^,  and  for  potatoes  (718  grms.)  7.6^. 
CoNSTA]srTi]s^iDi  ^  fouud  on  partaking  367-380  grms.  carbohydrates, 
chiefly  as  potatoes,  a  loss  of  only  0.4-0.7^.  In  the  experiments  of 
EuBiSTER,"  as  also  of  HuLTGREisr  and  Laxdeegren,^  with  rye  bread 
the  utilization  of  carbohydrates  was  less  complete,  although  the  loss 
in  a  few  cases  rose  even  to  10.4-10.9^.  It  at  least  follows  from  the 
experiments  made  thus  far  that  man  can  absorb  more  than  500 
grms.  carbohydrates  per  diem  without  difficulty. 

We  generally  consider  the  pancreas  as  the  most  important 
organ  in  the  digestion  and  absorption  of  amylaceous  bodies,  and  it 
is  a  question  how  these  bodies  are  absorbed  after  the  extirpation  of 
the  pancreas.  Minkowski  and  Abelmais^n  '  found  that  in  dogs 
.after  total  extirpation  of  the  pancreas  only  57-71^  of  the  amylaceous 
bodies  were  absorbed.  In  the  experiments  of  the  brothers  Cavaz-= 
ZANNi  °  only  47^  of  the  starch  introduced  was  used  by  the  animal 
with  the  pancreas  removed. 

Emulsification  seems  to  be  of  the  greatest  importance  in  the 
absorption  of  fats.  The  fats  may  be  absorbed  in  part  as  soaps,  but 
the  quantity  absorbed  in  this  form  is  very  small  as  compared  to  that 
which  is  absorbed  as  an  emulsion.  The  emulsion  is  undoubtedly 
the  most  important  form  in  which  fats  are  absorbed,  and  the  neutral 
fats  as  well  as  the  free  fatty  acids,  when  they  occur  in  large  quan- 
tities in  the  intestine,  form  an  emulsion.  The  fatty  acids  are  not 
absorbed  as  such  or  as  soaps.  The  investigations  of  I.  Munk,'  and 
later  confirmed  by  others,^  have  shown  that  the  fatty  acids  undergo 

'  L.  c.  and  Zeitsclir.  f .  Biologie,  Bd.  19. 
=  Zeitschr.  f.  Biologie,  Bd.  23. 
2  Ibid.,  Bd.  15. 
4  Nord.  med.  Arkiv.,  Bd.  21. 
^  L.  c.     See  Maly's  Jahresber.,Bd.  20. 
«  Centralbl.  f.  Pliysiol.,  Bd.  7. 
■>  Virchow's  Arch.,  Bd.  80. 

8  See  V.  Walther,  Du  Bois-Reymond's  Arch.,  1890,   and  Minkowski,  Arch, 
f  exp.  Path.  u.  Pharm.,  Bd.  21,  S.  373. 


ABSORPTION  OF  FATS.  335 

in  great  part  a  synthesis  into  neutral  fats  in  the  walls  of  the  intes- 
tine or,  according  to  Walthek,"  in  the  intestine,  and  carried  as 
sucli  by  the  stream  of  chyle  into  the  blood. 

Through  numerous  investigations  we  also  know  that  among 
all  the  nutritive  bodies  the  fats  are  the  only  substances  that  under 
ordinary  conditions  pass  into  the  blood  through  the  lymphatic 
vessels  and  the  thoracic  duct.  It  does  not  follow  from  this  that' 
all  or  the  greater  part  of  the  fat  takes  this  course,  and  according 
to  the  experiments  of  v.  Walther  and  0.  Fraxk  ^  the  reverse  is 
true,  namely,  only  a  very  small  part  of  the  fat,  or  at  least  of  the 
fatty  acids  partaken  of,  passes  into  the  chylous  vessels.  On  feeding 
dogs  with  fatty  acids  Walther  found  that  in  the  course  of  several 
hours  only  very  few  grammes  of  fat  were  carried  away  with  the 
lymph  current,  although  the  intestine  had  absorbed  40-50  grms.  fat. 
Fraxk  has  reached  a  similar  conclusion,  and  indeed  found  that  by 
the  excision  of  the  thoracic  duct  an  absorption  of  fatty  acids  took 
place  to  a  considerable  extent.  These  observations  do  not  seem  to 
be  applicable  to  the  absorption  of  neutral  fats  or  of  the  absorption 
in  man  under  normal  conditions.  Munk  and  Eosensteii^  in  their 
investigations  on  a  girl  with  lymph  fistula  found  QOfo  of  the  fat 
partaken  of  in  the  chyle,  and  of  the  total  quantity  of  fat  in  the 
chyle  only  4-5^  existed  as  soaps.  On  feeding  with  a  foreign  fatty 
acid,  such  as  erucic  acid,  they  found  ST,'^  of  the  introduced  body  as 
neutral  fat  in  the  chyle. 

The  completeness  with  which  fats  are  absorbed  depends,  under 
normal  conditions,  essentially  upon  the  kind  of  fat.  In  this  regard 
we  know,  especially  from  the  investigations  of  Muistk  '  and  Aii]sr- 
SCHIXK,*  that  the  varieties  of  fat  with  high  melting-points,  such  as 
mutton  tallow  and  especially  stearin,  are  not  so  completely  absorbed 
as  the  fats  with  low  melting-points,  such  as  hog-  and  goose-fat,  olive- 
oil,  etc.  The  kind  of  fat  also  has  an  influence  upon  the  rapidity  of 
absorption,  as  Muxk  and  Rosexsteust  found  that  solid  mutton- 
fat  was  absorbed  more  slowly  than  fluid  lipanin.  The  extent 
of  absorption  in  the  intestinal  tract  is  under  physiological  con- 
ditions very  considerable.  In  a  case  of  a  dog  investigated  by 
YoiT '  he  found  that  out  of  350  grms.  of  fat  (butter)  partaken,  346 

'  Walther,  1.  c. 

»  Du  Bois-Reymond's  Arch.,  1892. 
»  Virchow's  Arch.,  Bdd.  80  and  85. 
■•  Zeitschr.  f .  Biologie,  Bd.  26. 
« lUd.,  Bd.  9. 


336  DIGESTION. 

grms.  were  absorbed  \n  the  intestinal  canal,  and  according  to  the 
investigations  of  Eubnee  '  the  human  intestine  can  absorb  over  300 
grms.  fat  per  diem.  The  fats  are,  according  to  Rubber,  much 
more  completely  absorbed  when  free,  in  the  form  of  butter  or  lard, 
than  when  enclosed  in  the  cell-membranes,  as  in  bacon. 

The  bile  as  well  as  the  pancreas  is  of  the  greatest  importance 
in  the  absorption  of  fats. 

Through  numerous  observations  of  many  investigators,  such  as 
Bidder  and  Schmidt,'  Voit,'  Rohmann,*  Fr.  Muller,' 
I.  MuNK,°  and  others,  it  has  been  shown  that  the  exclusion  of  the 
bile  from  the  intestinal  tract  diminishes  the  absorption  of  fat  to 
such  an  extent  that  only  |  to  about  ^  of  the  quantity  of  fat  ordi- 
narily absorbed  undergoes  absorption.  In  icterus  with  entire 
exclusion  of  the  bile  a  considerable  decrease  in  the  absorption  of  fat 
is  noticed.  As  under  normal  conditions,  so  also  in  the  absence  of 
bile  in  the  intestine  the  more  readily  melting  parts  of  the  fats  are 
more  completely  absorbed  than  those  which  have  a  high  melting- 
point.  I.  MuNK  found  in  his  experiments  with  lard  and  mutton 
tallow  on  dogs  that  the  absorption  of  the  high  melting  tallow  was 
reduced  twice  as  much  as  the  lard  on  the  exclusion  of  the  bile 
from  the  intestine. 

We  also  learn  from  the  investigations  of  Rohm  ANN"  and 
I,  MuHK  that  in  the  absence  of  bile  the  relationship  between  fatty 
acids  and  neutral  fats  is  changed,  namely,  about  80-90^  of  the  fat 
existing  in  the  faeces  consists  of  fatty  acid,  while  under  normal 
conditions  the  fgeces  contain  1  part  neutral  fat  to  about  2-2|  parts 
free  fatty  acids.  We  cannot  positively  state  how  this  relatively 
increased  quantity  of  fatty  acids  in  the  fat  of  the  fgeces  is  produced 
on  the  exclusion  of  the  bile  from  the  intestine.  According  to  the 
investigations  of  Munk  it  does  not  in  the  least  depend  upon  the 
fact  that  the  fatty  acids  are  less  readily  absorbed  than  the  neutral 
fats,  for  just  the  reverse  is  the  case. 

There  is  no  doubt  that  the  bile  is  of  great  importance  in  the 
absorption  of  fats.  Still  there  is  also  no  doubt  that  rather  consider- 
able quantities  of  fat  may  be  absorbed  from  the  intestine  in  the 

1  Zeitschr.  f.  Biologie,  Bd.  15. 

2  Die  Verdauungssafte  und  der  Stoff wechsel,  S.  223. 

»  Beitrage  z.  Biologie,  Jubilaumssclirift  fiir  v.  Bischoff.     Stuttgart,  1883. 

*  Pflliger's  Arcli.,  Bd.  29. 

5  Sitzungsber.  d.  pbysik.-med.  Gesellscli.  zu  Wilrzburg,  1885. 

«  Virchow's  Arch.,  Bd.  122. 


ABSORPTION  OF  FATS.  337 

absence  of  bile.  What  relation  does  the  pancreas  bear  to  this  ques- 
tion ? 

According  to  Bernard  the  presence  of  pancreatic  juice  in  the 
intestine  is  necessary  in  the  absorption  of  fats.  This  view  has  found 
support  in  the  investigations  of  Minkowski  and  Abelmann  '  on 
the  absorption  of  fats  after  the  extirpation  of  the  pancreas  in  dogs. 
These  investigators  found  that  the  fat  introduced  in  the  food  was 
not  absorbed  at  all  after  the  complete  extirpation  of  the  pancreas. 
Milk  was  an  exception,  and  a  greater  or  smaller  part  (28-o3<^)  of 
its  fat  was  absorbed. 

It  is  difficult  to  state  anything  positive  about  the  significance  of 
these  observations,  since  there  are  other  investigations  which  have 
led  to  different  results.  Sandmeter  ■  found  in  his  experiments  on 
dogs  that  the  utilization  of  the  non-emulsified  fat  was  very  variable. 
Sometimes  no  fat  was  absorbed,  Avhile  at  other  times  in  the  same 
animal  30  or  even  78^  of  the  administered  fat  was  absorbed.  In  a 
series  of  experiments  administering  emulsified  fat  in  the  form  of 
milk  about  42^  was  absorbed.  Teichmann^  has  also  found  that 
after  ligaturing  the  pancreatic  duct  in  rabbits  the  absorption  of  fat 
was  not  noticeably  disturbed,  and  Fr.  Muller  ^  had  occasion  to 
observe  in  a  patient  with  pancreatic  fistula  that  in  human  beings  a 
considerable  absorption  of  fat  may  take  place  in  the  intestine  with- 
out pancreatic  juice. 

The  question  as  to  the  importance  of  the  pancreatic  juice  in  the 
absorption  of  fats  is  still  somewhat  disputed.  It  is  certain  at  least 
that  the  pancreatic  juice  is  of  very  great  importance  for  the 
absorption  of  fats,  and  it  is  also  certain  that  the  absorption  of 
fats  is  most  considerable  in  the  simultaneous  j^resence  of  bile  and 
pancreatic  juice  in  the  intestine.  We  can  give  no  explanation 
for  this  last  fact.  The  common  acceptance  is  that  to  form  an 
emulsion  of  the  fats  a  previous  splitting  is  necessary,  and  this  is. 
produced  by  the  pancreatic  juice,  accelerated  by  the  bile.  Many- 
doubts  have  been  raised  against  this  statement,  and  to  what  has  been 
said  already  (page  310)  we  must  add  the  following:  In  the  experi- 
ments of  Minkowski  and  ^Vbelmann  the  masses  of  fat  eliminated 

'  Ueber  die  Aiisnutzung  der  Nalirungsstoffe  nach  Pankreasexstirpation,  etc 
Inaug.  Diss.     Dorpat,  1890. 

«  Zeitschr.  f   Biologie,  Bd.  31. 

^  Mikroskop.  Beitr.  z.  Lelire  von  der  Fettresorption.  Diss.  Breslau,  1891. 
Cited  from  Neumeister,  Lelirb.  d.  pliysiol.  Chem.    Jena,  1897.     S.  336. 

*  Cited  from  Neumeister,  Lelirb.  d.  pbysiol.  Cliem.     Jena,  1897.     S.  337. 


338  DIGESTION. 

by  the  faeces  were  in  great  part  split  even  in  the  absence  of  the 
pancreas,  and  according  to  the  investigations  of  Hedon"  and  Wille  ^ 
an  abundant  splitting  of  the  fats  may  take  place  in  the  intestine 
even  in  the  absence  of  the  bile  as  well  as  of  the  pancreatic  juice. 
The  extent  of  action  of  microbes  and  other  unknown  factors  in 
this  splitting  has  not  yet  been  determined. 

From  these  experiments  we  cannot  draw  any  positive  conclusion 
as  to  the  importance  of  the  splitting  of  the  fat  for  emulsification 
under  normal  conditions,  because  on  the  exclusion  of  the  pancreatic 
juice  from  the  intestine  the  secretion  of  alkali  carbonates,  which 
are  important  in  the  emulsification  of  the  fats  as  well  as  for  the 
normal  processes  in  the  intestine,  suffers  essentially  in  quantity. 
In  the  experiments  of  Minkowski  and  Abelmanist  the  ethereal 
extract  of  the  fat  masses  of  the  f^ces  consisted  of  SO,*^  fatty  acids, 
which  were  chiefly  free  and  only  combined  with  alkali  to  a  slight 
.extent. 

V.  Harlet  ^  has  made  experiments  on  the  absorption  of  fats 
(milk)  in  dogs  with  extirpated  pancreas.  The  passage  of  the  fats 
from  the  stomach  to  the  intestine  in  these  dogs  was  retarded,  and 
Harlet  found  not  only  as  much  fat  in  the  intestinal  tract  as 
-was  introduced,  but  also  a  little  which  was  derived  from  the  secre- 
tions and  excretions  of  the  intestine.  This  experiment  gave  entirely 
different  results  from  Abelmann's  experiment,  and  Harlet  ex- 
plains this  by  the  fact  that  in  Abelmakk's  experiment  the  action 
of  intestinal  bacteria  was  not  excluded  or  reduced  to  a  minimum, 
as  in  his. 

The  fact  that  milk  is  the  only  form  in  which  fat  can  be  absorbed 
in  dogs  in  the  absence  of  pancreatic  juice  (Miistkowski)  may, 
according  to  him,  be  explained  in  the  fact  that  this  fat  emulsion  is 
permanent  in  acid  as  well  as  in  neutral  or  alkaline  reaction.  From 
these  observations,  and  from  the  confirming  observations  of  Sand- 
meter  that  a  considerable  absorption  of  other  fats  may  take  place 
in  dogs  with  extirpated  pancreas  when  with  the  fat  food  we  add 
finely  chopped  ox-pancreas,  Minkowski  suggests  that  the  proteids 
are  of  the  greatest  importance  in  the  emulsification  of  fats.  This 
view  is  in  accordance  with  the  older  statements  of  Bernard  and 
KuHNE,^  but  has  not  been  the  subject  of  thorough  research. 

1  See  Maly's  Jahresber.,  Bd.  22,  S.  38. 
«  Journal  of  Physiol., Vol.  18. 
^  See  page  311. 


ABSORPTION  IN  GENERAL.  339 

The  soluble  salts  are  also  absorbed  with  the  water.  The  proteids 
and  peptone  which  can  dissolve  a  considerable  quantity  of  salts, 
such  as  earthy  phosphates  which  are  otherwise  insoluble  in  alkaline 
water,  are  of  great  importance  in  the  absorption  of  such  salts. 

Water,  according  to  the  experiments  of  v.  Meking,'  as  also  of 
Glet  and  Eondeau,^  on  dogs  is  not  absorbed  to  any  appreciable 
amount  in  the  stomach.  Alcohol,  on  the  contrary,  is  absorbed  to 
a  great  extent  in  the  stomach.  The  extent  of  the  absorjation  of 
dissolved  bodies  seems  to  be  dependent  upon  the  concentration  of 
the  solution,  and  according  to  Bkaxdl  '  the  difference  between  the 
absorption  in  the  stomach  and  intestine  consists  in  that  the  absorp- 
tion in  the  first  organ  takes  place  better  in  greater  concentration 
and  in  the  second  in  less  concentration.  Thus,  for  examj)le,  a  solu- 
tion of  cane-  or  grape-sugar  is  most  completely  absorbed  by  the 
intestine  in  a  concentration  of  0.5^.  With  increasing  concentration 
the  absorption  diminishes,  and  in  a  concentration  of  5^  a  disturb- 
ance takes  place.  In  the  stomach  an  appreciable  absorption  first 
occurs  with  a  concentration  of  5^,  and  then  increases  to  about  20^. 
The  presence  of  other  bodies  which  cause  an  irritation  on  the 
mucous  membrane  seems  to  be  valuable  for  absorption,  and  accord- 
ing to  Braistdl  chloral  hydrate,  sugar,  and  potassium-iodide  solu- 
tions are  better  absorbed  in  the  presence  of  alcohol  than  from  pure 
watery  solution. 

The  soluble  constituents  of  the  digestive  secretions  may,  like 
other  dissolved  bodies,  be  absorbed,  as  is  demonstrated  by  the 
passage  of  peptone  into  urine;  the  enzymes  may  also  be  absorbed. 
The  occurrence  of  urobilin  in  urine  attests  the  absorption  of  the 
bile-constituents  under  physiological  conditions  notwithstanding  the 
question  as  to  the  occurrence  of  very  small  traces  of  bile-acids  in 
the  urine  is  disputed.  The  absorption  of  bile-acids  by  the  intestine 
seems  to  be  positively  proven  by  other  observations.  Tappeixer  * 
introduced  a  solution  of  bile-salts  of  a  known  concentration  into  an 
intestinal  knot,  and  after  a  time  investigated  the  contents.  He 
found  that  in  the  jejunum  and  the  ileum,  but  not  in  the  duodenum, 
an  absorption  of  bile-acids  took  place,  and  further  that  of  the  two 

1  Centralbl.  f.  Physiol.,  Bd.  7,  S.  533. 
»  C.  R.  Soc.  de  Biol.,  1893. 

*  Zeitschr.  f.  Biologie,  Bd.  29.     This  contains  all  the  older  literature  relat- 
ing to  this  question. 

*  Wien.   Sitzungsber.,  Bd.  77. 


340  DIGESTION. 

bile-acids  only  the  glycocholic  acid  was  absorbed  in  the  Jejnniim, 
Further,  Schiff  '  long  ago  expressed  the  opinion  that  bile  under- 
goes an  intermediate  circulation,  in  such  wise  that  it  is  absorbed 
from  the  intestine,  then  carried  to  the  liver  by  the  blood,  and  lastly 
eliminated  from  the  blood  by  this  organ.  Although  this  view  has 
.met  with  some  opposition,  still  its  correctness  seems  to  be  established 
by  the  researches  of  various  investigators,  and  more  recently  by 
Prevost  and  Binet,''  as  also  and  specially  by  Stadelman'N'  and  his 
pupils.'  After  the  introduction  of  foreign  bile  into  the  intestine  of 
an  animal  the  foreign  bile-acids  appear  again  in  the  secreted  bile. 

Little  is  known  concerning  the  forces  taking  part  in  absorption. 
Osmosis  and  filtration  were  formerly  considered  as  the  most  impor- 
tant factors.  But  as  in  regard  to  the  peptones,  whose  formation  in 
the  digestion  was  considered  as  taking  place  especially  in  the 
interest  of  a  facilitated  osmosis  and  filtration,  but  whose  conditions 
have  been  found  quite  different  and  much  more  complicated,  so  in 
the  absorption  theory  there  is  a  still  greater  contrast  between  former 
and  present  views,  the  latter  inclining  to  the  theory  that  absorption 
is  a  process  connected  with  the  vital  properties  of  the  cells  (Hoppe- 
Seyler*).  Investigations  in  this  direction  have  been  made  by 
Heiden^hain  '  and  his  pupils  Rohmann^,  and  Gumilewsky  ' ;  and 
these  investigations  have  shown  that  the  cells  take  an  active  part  in 
the  absorption,  and  that  this  action  is  independent  of  the  processes 
caused  by  an  unequal  diffusibility  of  the  different  bodies.  For 
example,  in  a  solution  which  contains  equal  quantities  of  grape- 
sugar  and  sodium  sulphate  the  sugar  will  be  almost  completely 
absorbed  in  a  certain  time,  while  the  salt,  which  has  the  greater 
diffusibility,  still  remains  in  considerable  amounts  in  the  intestine. 
According  to  the  latest  investigations  of  Heidekhaiit  ^  on  the 
absorption  of  blood-serum  and  common-salt  solutions  from  the 
intestine  of  dogs,  no  doubt  can  now  exist  that  the  cells  have  a 
special  physiological  force  besides  wliich  under  certain  circumstances 
osmosis  may  operate,  but  under  other  circumstances  an  absorption 

1  Pfliiger's  Arcb.,  Bd.  3. 

2  Compt.  rend.,  Tome  106. 
2  See  reference,  page  224. 
4  Physiol.  Chem.,  S.  348. 

6  Pfliiger's  Arcli.,  Bdd.  43  and  56. 
^  lUd.,  Bd.  41. 
'  Ibid  ,  Bd,  39. 
^  Ibid.,  Bd.  56. 


ABSORPTION  IN  GENERAL.  341 

may  take  place  with  the  entire  exclusion  of  osmosis.  It  is  also 
known  that  certain  pigments  are  absorbed  and  others  not,  and  the 
-cells  seem  to  have  the  property  of  discrimiuating  between  the 
different  substances.  The  absorption  of  dissolved  bodies  seems  to 
be  connected  with  a  specific  activity  of  the  living  cell,  the  living 
protoplasm. 

In  the  absorption  of  bodies  not  dissolved,  of  the  emulsified  fats, 
forces  take  part  which  are  not  known.  That  the  bile  j^erforms  the 
most  important  part  in  the  absorption  of  fats  is  very  generally 
admitted,  but  how  the  bile  acts  in  this  process  is  not  yet  deter- 
mined. Y.  WiSTiNGHAUSEN" '  has  found  that  fat  rises  higher  iu  a 
capillary  tube  moistened  with  bile  than  when  moistened  with 
water,  and  further  that  fluid  fat  filters  more  easily  through  a  dead 
membrane  dipped  in  bile  than  when  dipped  in  watei'.  From  these 
observations,  whose  correctness  has  lately  been  disputed  by  Gad  and 
Groper,^  the  inference  has  been  drawn  that  bile  facilitates  the 
capillary  attraction  and  thereby  accelerates  the  absorption  of  the 
fats.  The  epithelium  layer  of  the  intestinal  mucous  membrane 
cannot  be  compared  with  a  dead  membrane  soaked  in  water,  and  it 
is  therefore  doubtful  if  the  above-mentioned  action  of  bile  can  have 
any  influence  on  the  absorption  of  fats  in  the  intestine.  That  the 
absorption  of  fats  is  caused  by  the  lymphoid  migratory  cells 
(Zawarykhs","  Schafer')  is  disputed  by  Gruenhagen  '  and 
Heidenhain."  According  to  them,  the  fat  takes  its  Avay  chiefly 
through  the  epithelium  cells.  How  these  last  act  is,  like  the  nature 
of  their  action  in  absorption,  enveloped  in  darkness. 

'  See  the  translation  of  Wistinghausen's  dissertation  by  Steiaer  in  Du  Bois- 
Eeymond's  Arch.,  1873. 

'  Du  Bois-Keymond's  Arcli.,  1889. 

'  Pfluger's  Arch.,  Bd.  31. 

■»  Ibid. ,  Bd.  33. 

'Arch.  f.  mikroskop.  Anat.,  Bd,  29. 

«Ptiuger's  Arch,,  Bd.  43. 


CHAPTER  X. 

TISSUES  OF  THE  CONNECTIVE   SUBSTANCE. 

I.  The  Connective  Tissues. 

The  form-elements  of  the  typical  connective  tissues  are  cells 
of  varions  kinds,  of  a  not  very  well  known  chemical  composition, 
and  gelatin-yielding  fibrils,  which  like  the  cells  are  imbedded  in 
an  interstitial  or  intracellular  substance.  The  fibrils  consist  of 
collagen.  The  interstitial  substance  contains  chiefly  mucin  besides 
serglobulin  and  seralbumin,  which  occur  in  the  parenchymatous 
fluid  (Loebisch"). 

The  connective  tissue  also  often  contains  flbres  or  formations 
consisting  of  elastin,  sometimes  in  such  great  quantities  that  the 
connective  tissue  is  transformed  into  elastic  tissue.  According  to 
Mall  ^  a  third  variety  of  fibres,  the  reticular  fibres,  also  occur,  and 
these  according  to  Siegfried  consist  of  reticulin. 

If  finely  divided  tendons  are  extracted  in  cold  water,  the 
albuminous  bodies  soluble  in  the  nutritive  fluid  in  addition  to  a 
little  mucin  are  dissolved.  If  the  residue  is  extracted  with  half- 
saturated  lime-water,  then  the  mucin  is  dissolved  (Rollett,^ 
Loebisch)  and  may  be  precipitated  from  the  filtered  extract  by 
saturating  with  acetic  acid.  The  digested  residue  contains  the 
fibrils  of  the  connective  tissue  together  with  the  cells  and  the  elastic 
substance. 

The  fibrils  of  the  connective  tissue  are  elastic  and  swell  slightly 
in  water,  somewhat  more  in  dilute  alkalies  or  in  acetic  acid.  On 
the  other  hand,  they  shrink  by  the  action  of  certain  metallic  salts, 
such  as  ferrous  sulphate  or  mercuric  chloride,  and  tannic  acid, 
which  forms  an  insoluble  combination  with  the  collagen.     Among 

'  Zeitsclir.  f.  physiol.  Chem.,  Bd.  10. 

»Kgl.  Sachs.  Gesellscb.  d.  Wissensch.,  1891,  Bd.  17,  Math.-phys.  Klasse. 

»  Wien.  Sitzungsber.,  Bd.  39. 

349 


CONNECTIVE  TISsUE  AND   CARTILAGE.  343 

these  combinations,  which  prevent  putrefaction  of  the  collagen, 
that  with  tannic  acid  has  been  fonnd  of  the  greatest  technical 
importance  in  the  preparation  of  leather.  In  regard  to  tendoit 
mucin  see  page  45,  and  in  regard  to  collagen,  gelatin,  elastin,  and. 
reticulin,  pages  51-56. 

The  tissues  described  under  the  names  mucous  or  gelatinous' 
tissues  are  characterized  more  by  their  physical  than  their  chemical 
properties  and  have  been  but  little  studied.  So  much,  however,  is> 
known,  that  the  mucous  or  gelatinous  tissues  contain,  at  least  in- 
certain  cases,  as  in  the  acalephas,  no  mucin. 

The  umbilical  cord  is  the  most  accessible  material  for  the  inves- 
tigation of  the  chemical  constituents  of  the  gelatinous  tissues.  The 
mucin  occurring  therein  has  been  described  on  page  45.  C.  Th. 
MoENEE  '  has  found  a  mucoid  in  the  vitreous  humor  which  contains 
12.27^  nitrogen  and  1.19^  sulphur. 

Young  connective  tissue  is  richer  in  mucin  than  old.  Hallt- 
BUETOX  '^  found  an  average  of  7.66  p.  m.  mucin  in  the  skin  of  very 
young  children  and  only  3.85  p.  m.  in  the  skin  of  adults.  In 
so-called  myxoedema,  in  which  a  reformation  of  the  connective  tissue 
of  the  skin  takes  place,  the  quantity  of  mucin  is  also  increased. 

II.  Cartilage. 

Cartilaginous  tissue  consists  of  cells  and  an  originally  hyaline 
matrix,  which,  however,  may  become  changed  in  such  wise  that 
there  appears  in  it  a  network  of  elastic  fibres  or  connective-tissue 
fibrils. 

Those  cells  that  offer  great  resistance  to  the  action  of  alkalies 
and  acids  have  not  been  carefully  studied.  According  to  former 
views,  the  matrix  was  considered  as  consisting  of  a  body  analogous 
to  collagen,  so-called  clionclrigen,  which  under  similar  conditions 
passes,  like  collagen,  into  a  corresponding  gelatin  called  chondrin 
or  cartilage-gelatin.  The  recent  investigations  of  Moeochowetz  * 
and  others,  but  especially  those  of  C.  Th.  Moenee,*  have  shown 
that  the  matrix  of  the  cartilage  consists  of  a  mixture  of  collagen 
with  other  bodies. 

>  Zeitschr.  f.  pliysiol.  Chem.,  Bd.  18,  S.  250. 

*  Mucin  in  Myxoedema.  Furtlier  Analyses.  Kings  College.   Collected  Papers 
No.  1.  1893. 

*  Verliandl.  d.  naturhist.-med.  Vereins  zu  Heidelberg,  Bd.  1,  Heft  5. 
4  Skand.  Arch.  f.  Physiol. ,  Bd.  1. 


344  TI88UE8  OF  THE  CONNECTIVE  SUBSTANCE. 

The  tracheal,  thyroideal,  cricoidal,  and  arytenoidal  cartilages  of 
full-grown  cattle  contain,  according  to  Mornee,  four  constituents 
in  the  matrix,  namely,  cliondromucoid^  cJiondroitin- sulphuric  acid, 
collagen,  and  an  albuminoid. 

Chondromucoid.  This  body,  according  to  Moeistbr,  has  the 
composition  C  47.30,  H  6.42,  N  12.58,  S  2.42,  0  31.28^.  Sulphur 
is  in  part  loosely  combined  and  may  be  split  off  by  the  action  of 
alkalies,  and  a  part  separates  as  sulphuric  acid  when  boiled  with 
hydrochloric  acid.  Chondromucoid  is  decomposed  by  dilute  alkalies 
and  yields  alkali  albuminate,  peptone  substances,  chondroitin- 
sulphuric  acid,  alkali  sulphides,  and  some  alkali  sulphates.  On 
boiling  with  acids  it  yields  acid  albuminate,  peptone  substances, 
chondroitin-sulphuric  acid,  and  on  account  of  the  further  decom- 
position of  this  last  body  sulphuric  acid  and  a  reducing  substance 
are  formed.  According  to  Schmiedeberg  '  chondromucoid  is  a 
combination  of  chondroitin-sulphuric  acid  with  proteid. 

Chondromucoid  is  a  white,  amorphous,  acid-reacting  powder 
"which  is  insoluble  in  water,  but  dissolves  easily  on  the  addition  of 
a  little  alkali.  This  solution  is  precipitated  by  acetic  acid  in  great 
excess  and  by  small  quantities  of  mineral  acids.  The  precipitation 
may  be  retarded  by  neutral  salts  or  by  chondroitin-sulphuric  acid. 
The  solution  containing  NaCl  and  acidified  with  HCl  is  not  pre- 
cipitated by  potassium  ferrocyanide.  Precipitants  for  chondro- 
mucoid are  alum,  ferric  chloride,  sugar  of  lead  or  basic  lead  acetate. 
Chondromucoid  is  not  precipitated  by  tannic  acid,  and  it  may  by 
its  presence  prevent  the  precipitation  of  gelatin  by  this  acid.  It 
gives  the  usual  color  reactions  for  proteids,  namely,  with  nitric 
acid,  with  copper  sulphate  and  alkali,  with  Millon's  and  Adam- 
KiEWicz's  reagents. 

Chondroitin-sulphuric  Acid,  chondroitic  acid.  This  acid, 
which  was  first  prepared  pure  from  cartilage  by  C.  Th.  Morner 
and  identified  by  him  as  an  ethereal  sulphuric  acid,  occurs  accord- 
ing to  MoRNER  *  in  all  varieties  of  cartilage  and  also  in  the  tunica 
intima  of  the  aorta.  Oddi  '  has  also  found  it  in  livers  with  amyloid 
degeneration.  According  to  Schmiedeberg  the  acid  has  the 
formula  C,gH3,]SrS0j,.  In  regard  to  the  chemical  constitution  of 
this  acid  the  investigations  of  Schmiedeberg  have  led  to  the 
following : 

1  Arct.  f.  exp.  Path,  u.  Pharm.,  Bd.  28. 
»  Upsala  Liikarefs  Forh.,  Bd.  29. 

2  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  33. 


CnOXDROITmSULPUURIC  ACID.  345 

As  first  products  this  acid  yields  sulphuric  acid  and  a  nitrog- 
enous substance,  chotuh^oitin,  according  to  the  following  equation: 

C„H„XSO,,  +  H,0  =  H,SO,  +  C„H„NO,,. 

Chondroitin,  which  is  similar  to  gum  arable  and  which  is  a  mono- 
basic acid,  yields  acetic   acid  and  a  new  nitrogenous  substance 
cJiondrosin,   as  cleavage  products,    on    decomposition   with   dilute 
mineral  acids: 

C.H„NO„  +  3H,0  =  3C,H,0,  +  C,,H,.NO„ 

Chondrosin,  which  is  also  a  gummy  substance  soluble  in  water,  is  a 
monobasic  acid  and  reduces  copper  oxide  in  alkaline  solution  even 
more  strongly  than  dextrose.  It  is  dextrogyrate  and  represents  the 
reducing  substance  obtained  by  previous  investigators  in  an  impure 
form  on  boiling  cartilage  with  an  acid.  The  products  obtained  on 
decomposing  chondrosin  with  barium  hydrate  tend  to  show  tliat 
chondrosin  contains  the  atomic  groups  of  glycuronic  acid  and 
glucosamine. 

Chondroitin-sulphuric  acid  appears  as  a  white  amorphous 
powder,  which  dissolves  very  easily  in  water,  forming  an  acid  solu- 
tion and,  when  sufficiently  concentrated,  a  sticky  liquid  similar  to 
a  solution  of  gum  arable.  Nearly  all  of  its  salts  are  soluble  in 
water.  The  neutralized  solution  is  precipitated  by  tin  chloride, 
basic  lead  acetate,  neutral  ferric  chloride,  and  by  alcohol  in  the 
presence  of  a  little  neutral  salt.  The  solution,  on  the  other  hand, 
is  not  precipitated  by  acetic  acid,  tannic  acid,  potassium  ferro- 
cyanide  and  acid,  sugar  of  lead,  mercuric  chloride,  or  silver  nitrate. 
Acidified  solutions  of  chondroitln-sulphates  cause  a  precipitation 
when  added  to  solutions  of  gelatin  or  proteid. 

Chondromucoid  and  chondroitin-sulphuric  acid  may  be  prepared 
according  to  Morxer  '  by  exacting  finely  cut  cartilage  with  water, 
which  dissolves  the  preformed  chondroitin-sulphuric  acid  besides 
some  chondromucoid.  In  this  watery  extract  the  chondroitin-sul- 
phuric acid  prevents  the  precipitation  of  the  chrodromucoid  by 
means  of  an  acid.  If  2-4  p.  m.  HCl  is  added  to  this  watery  extract 
and  warmed  on  the  water-bath,  the  chondromucoid  gradually 
separates,  while  the  chondroitin-sulphuric  acid  and  the  rest  of 
the  chondromucoid  remain  in  the  filtrate.  If  the  cartilage,  which 
has  been  lixiviated,  at  the  temperature  of  the  body,  with  water,  is 
extracted  with  hydrochloric  aoid  of  2-3  p.  m.  until  the  collagen  is 

»L.  c. 


346  TISSUES  OF  THE  CONNECTIVE  SUBSTANCE. 

coaverted  into  gelatin  and  dissolved,  the  remaining  cliondromucoid 
may  be  removed  from  tlie  insoluble  residue  by  dilute  alkali  and 
precipitated  from  the  alkaline  extract  by  an  acid.  It  may  be 
purified  by  repeated  solution  in  water  with  the  aid  of  a  little 
alkali,  precipitating  by  an  acid  and  then  treating  with  alcohol  and 
ether. 

The  pre-existing  chondroitin-sulphnric  acid,  or  that  formed  by 
the  decomposition  of  chondromucoid,  is  obtained  by  lixiviating  the 
cartilage  with  a  bfo  caustic-alkali  solution.  The  alkali  albuminate 
formed  by  the  decomposition  of  the  chondromucoid  can  be  removed 
from  the  solution  by  neutralization,  then  the  peptone  precipitated 
by  tannic  acid,  the  excess  of  this  acid  removed  with  sugar  of  lead, 
and  the  lead  separated  from  the  filtrate  by  H^S.  If  further  purifi- 
cation is  necessary,  the  acid  is  precipitated  with  alcohol,  the  pre- 
cipitate dissolved  in  water,  this  solution  dialyzed  and  precipitated 
again  with  alcohol, — this  solution  in  water  and  precipitating  with 
alcohol  being  repeated  a  few  times, — and  lastly  the  acid  is  treated 
with  alcohol  and  ether. 

ScHMiEDEBERG '  prepared  the  acid  from  the  septum  narium  of 
the  pig  according  to  the  following  method:  The  finely  divided 
cartilage  is  first  exposed  to  artificial  pepsin  digestion  and  then  care- 
fully washed  with  water  and  the  insoluble  residue  treated  with  2-3^ 
hydrochloric  acid.  This  cloudy  liquid  containing  hydrochloric  acid 
is  j)recipitated  Avith  alcohol  (about  \  vol.)  and  the  clear  filtrate 
treated  with  absolute  alcohol  and  some  ether.  The  precipitate, 
consisting  chiefly  of  a  combination  or  a  mixture  of  chondroitin- 
sulphuric  acid  and  gelatin  peptone  (pepto-chondrin),  is  first  washed 
with  alcohol  and  then  with  water.  It  is  then  dissolved  in  alkaline 
water  and  the  basic  alkali  combination  precipitated  from  this  solu- 
tion by  the  addition  of  alcohol,  whereby  the  gelatine-peptone  alkali 
remains  in  solution.  The  precipitate  is  purified  by  repeated  solu- 
tion in  alkaline  water  and  precipitated  by  alcohol.  To  obtain 
chondroi tin-sulphuric  acid  entirely  free  from  chondroitin  it  is  more 
advantageous  to  prepare  the  potassium-copper  combination  of  the 
acid  from  the  alkaline  solution  by  the  alternate  addition  of  copper 
acetate  and  caustic  potash  and  precipitating  with  alcohol.  The 
reader  is  referred  to  the  original  article  for  more  details. 

The  collagen  of  the  cartilage  gives,  according  to  Moenee,  a 
gelatin  which  contains  only  16.4,'^  IST  and  which  can  hardly  be  con- 
sidered identical  with  ordinary  gelatin. 

In  the  above-mentioned  cartilages  of  full-grown  animals  the 
chondroitin-sulphuric  acid  and  chondromucoid,  perhaps  also  the 
collagen,  are  found  surrounding  the  cells  as  round  balls  or  lumps. 
These  balls  (Mornek's  chondrin-balls),  which  give  a  blue  color 

'  Arch.  f.  Exp.  Path.  u.  Pharm.,  Bd.  28. 


COMPOSITION^  OF  CARTILAGE.  347 

with  methyl-violet,  lie  in  the  meshes  of  a  trabecular  structure, 
which  is  colored  when  brought  in  contact  with  tropaeolin. 

The  albuminoid  is  a  nitrogenized  body  which  contains  loosely 
combined  sulphur.  It  is  soluble  with  difficulty  in  acids  and  alka- 
lies, and  resembles  keratin  in  many  respects,  but  diiiers  from  it  by 
being  soluble  in  gastric  juice.  In  other  respects  it  is  more  similar 
to  elastin,  but  differs  from  this  substance  by  containing  sulphur. 
This  albuminoid  gives  the  color  reactions  of  the  albuminous  bodies. 

The  preparation  of  cartilage-gelatin  and  albuminoid  may  be 
performed  according  to  the  following  method  of  Morxer:  First 
remove  the  cliondromucoid  and  chondroitin-sulphuric  acid  by 
extraction  with  dilute  caustic  potash  (0.2-0.5,^),  remove  the  alkali 
from  the  remaining  cartilage  by  water,  and  then  boil  with  water  in 
a  Papix's  digestor.  The  collagen  passes  into  solution  as  gelatin, 
while  the  albuminoid  remains  undissolved  (contaminated  by  the 
cartilage-cells).  The  gelatin  may  be  purified  by  precipitating 
with  sodium  sulphate,  which  must  be  added  to  saturation  in  the 
faintly  acidified  solution,  redissolving  the  precipitate  in  water, 
dialyzing  well,  and  ^precipitating  with  alcohol. 

According  to  Morner,  no  albuminoid  is  found  in  young  carti- 
lage, but  only  the  three  first-mentioned  constituents.  Nevertheless 
the  young  cartilage  contains  about  the  same  amounts  of  nitrogen 
and  mineral  substances  as  the  old. 

Hoppe-Setler  '  found  in  fresh  human  rib-cartilage  676.7  p.  m. 
water,  301.3  p.  m.  organic  and  32  p.  m.  inorganic  substance,  and  in 
the  cartilage  of  the  knee-joint  735.9  p.  m.  water,  248. 7  p.  m.  organic 
and  15.-4  p.  m.  inorganic  substance.  Pickardt'  found  402-574 
p.  m.  water  and  72.86  p.  m.  ash  (no  iron)  in  the  laryngeal  cartilage 
of  oxen.  The  ash  of  cartilage  contains  considerable  amounts  (even 
800  p.  m.)  of  alkali  sulphate,  which  probably  does  not  exist  orig- 
inally as  such,  but  is  produced  in  great  part  by  the  calcination  of  the 
chondroitin-sulpliuric  acid  and  the  chondromucoid.  The  analyses 
of  the  ash  of  cartilage  therefore  cannot  give  a  correct  idea  of  the 
quantity  of  mineral  bodies  existing  in  this  substance.  Petersex 
and  Soxhlet'  have  found  940  p.  m.  NaCl  in  the  ash  from  the 
cartilage  of  a  shark,  and  such  .cartilage  can  scarcely  contain  quanti- 
ties of  chondromucoid  or  chondroitin-sulphuric  acid  worth  men- 
tioning.    The  cartilage  of  the  ray  {Baja  bat  is  Lix.),  which  has 

'  Cited  from  Killine,  Lehrb.  d.  physiol.  Chem.,  1868,  S.  387. 
'  Centralbl.  f.  Physiol.,  Bd.  6,  S.  735. 
»  Journ.  f.  pralit.  Cliem.  (N.  F.),  Bd.  7. 


348  TISSUES  OF  THE  CONNECTIVE  SUBSTANCE. 

been  investigated  by  Lonnbbrg,"  contains  no  albuminoid  and  only 
a  little  chondromucoid,  but  a  large  proportion  of  chondroitin- 
sulphuric  acid  and  collagen. 

The  Cornea.  The  corneal  tissue,  which  is  considered  by  many 
investigators  to  be  related  to  cartilage  in  a  chemical  sense,  contains 
traces  of  proteid  and  a  collagen  as  chief  constituent,  which  C.  Th, 
MoENER^  claims  contains  16.95^  IST.  According  to  him  it  also 
contains  a  mucoid  which  has  the  composition  C  50.16,  H  6.97, 
N  12.79,  and  S  2.07^.  On  boiling  with  dilute  mineral  acid  this 
mucoid  yields  a  reducing  substance.  The  globulins  found  by  other 
investigators  in  the  cornea  are  not  derived  from  the  matrix,  accord- 
ing to  MoRifER,  but  from  the  layer  of  epithelium.  According  to 
MoRNER,  Descemet's  membrane  consists  of  membranin  (page 
47),  which  contains  14.77^  N  and  0.90^  S. 

In  the  cornea  of  oxen  His'  found  758.3  p.  m.  water,  203.8 
p.  m.  gelatin-forming  substance,  28.4  p.  m.  other  organic  substance, 
besides  8.1  p.  m.  soluble  and  1.1  p.  m.  insoluble  salts. 

III.  Bone. 

The  bony  structure  proper,  when  free  from  other  formations 
occurring  in  bones,  such  as  marrow,  nerves,  and  blood-vessels,  con- 
sists of  cells  and  a  matrix. 

The  cells  have  not  been  closely  studied  in  regard  to  their 
chemical  constitution.  On  boiling  with  water  they  yield  no  gela- 
tin. They  contain  no  keratin,  which  is  not  usually  present  in  the 
bony  structure  (Herbert  Smith  ^),  but  they  may  contain  a  sub- 
stance which  is  similar  to  elastin. 

The  matrix  of  the  bony  structure  contains  two  chief  constitu- 
ents, namely,  an  organic  substance,  ossein,  and  the  so-called  bone- 
earths,  lime-salts,  enclosed  in  or  combined  with  it.  If  bones  are 
treated  with  dilute  hydrochloric  acid  at  the  ordinary  temperature, 
the  lime-salts  are  dissolved  and  the  ossein  remains  as  an  elastic 
mass,  preserving  the  shape  of  the  bone.  This  ossein  is  generally 
considered  identical  with  the  collagen  of  the  connective  tissue. 
The  ossein  in  the  bones  of  certain  aquatic  fowls  and  fishes  can 
hardly  be  considered  identical  with  this  collagen  (Fremt  '). 

'  Upsala  Lakaref .  Forh.,  Bd.  24;  also  Maly's  Jahresber.,  Bd.  19,  S.  335. 

«  Zeitschr.  f.  pliysiol.  Chem.,  Bd.  18. 

s  Cited  from  Gamgee,  Physiol.  Claem.,  1880,  p.  451. 

-»  Zeitschr.  f.  Biologie,  Bd.  19. 

^  Annal.  de  Chim.  et  de  pbys.  (3),  Tome  43,  and  Compt.  rend.,  Tome  39. 


BONE  AND   BONE  EARTHS.  349 

The  inorganic  constituents  of  the  bony  structure,  the  so-called 
hone-earths,  which  remain  after  the  complete  calcination  of  the 
organic  substance  as  a  white,  brittle  mass,  consist  chiefly  of  calciam 
and  phosj^horic  acid,  but  also  contain  carbon  dioxide  and,  in  smaller 
amounts,  magnesium,  chlorine,  and  fluorine.  Alkali  sulphate  and 
iron,  which  have  been  found  in  bone-ash,  do  not  seem  to  belong 
exactly  to  the  bony  substance,  but  to  the  nutritive  fluids  or  to  the 
other  constituents  of  bones.  According  to  Gabriel  '  potassium 
and  sodium  are  essential  constituents  of  bone-earth. 

The  opinions  of  investigators  differ  somewhat  as  to  the  manner 
in  which  the  mineral  bodies  of  the  bony  structure  are  combined 
with  each  other.  Chlorine  and  fluorine  are  present  in  the  same 
form  as  in  apatite  (CaFl^,3Ca3P20g).  If  we  eliminate  the  mag- 
nesium, the  chlorine,  and  the  fluorine,  the  last,  according  to 
Ga]?riel,  occurring  only  as  traces,  the  remaining  mineral  bodies 
form  the  combination  ^{Cii^'P ^0 ^)Ca.Q'Q ^.  According  to  Gabriel 
the  simplest  expression  for  the  comi^osition  of  the  ash  of  bones 
and  teeth  is  (Ca,(PO;),  +  Ca^HP^O,^  -\-  Aq),  in  which  2-3^  of 
the  lime  is  replaced  by  magnesia,  potash,  and  soda,  and  4-G^  of 
the  phosphoric  acid  by  carbon  dioxide,  chlorine,  and  fluorine. 

Analyses  of  bone-earths  have  shown  that  the  mineral  constitu- 
ents exist  in  rather  constant  proportions,  which  is  nearly  the  same 
in*  different  animals.     As  example    of  the  composition    of   bone 
earth  we  give  here  the  analyses  of  Zalesky.'^     The  figures  represent 
parts  per  thousand. 

Man. 

Calcium  phosphate,  CaaPjOe 838.9 

Magnesium  phosphate,  MgaPjO  8 10.4 

Calciuui  combined  with  COj,  Fl,  and  CI.     76.5 

CO2 57.3 

Chlorine 1.8 

Fluorine 3.3 

Some  of  the  CO2  is  always  lost  on  calcining,  so  that  the  bone-ash  does  not 
contain  the  entire  CO3  of  the  bony  substance. 

Ad.  Carnot  '  found  the  following  composition  for  the  bone-ash 
of  man,  ox,  and  elephant : 

Man.  Ox.  Elephant. 

Femur            Femur  Femur.  Femur, 
(body).             (head). 

Calcium  phosphate 874.5            878.7  857.2  900.3 

Magnesium  phosphate 15.7               17.5  15.3  19.6 

Calcium  fluoride 3.5                 3.7  4.5  4.7 

Calcium  chloride     2.3                 3.0  3.0  2.0 

Calcium  carbonate 101.8               92.3  119.6  72.7 

Iron  oxide 1.0                1.3  1.3  1.5 

'  Zeitschr.  f.  physiol.  Chem.,  Bd.  18. 

'  Hoppe-Seyler,  Med.  chem.  Untersuch.,  S.  19. 

*  Comp.  rend.,  Tome  114. 


Ox. 

Tortoise. 

Guinea-pig. 

860.9 

859.8 

873.8 

10.2 

13  6 

10.5 

73.6 

63.2 

70.3 

62.0 

52.7 

2.0 

.... 

1.3 

3.0 

2.0 

350  TISSUES  OF  THE  CONNECTIVE  SUBSTANCE. 

The  quantity  of  organic  substance  in  the  bones,  calculated  from 
the  loss  of  weight  in  burning,  varies  somewhat  between  300  and  520 
p.  m.  This  variation  may  in  part  be  explained  by  the  difficulty  in 
obtaining  the  bony  substance  entirely  free  from  water,  and  partly 
by  the  very  variable  amount  of  blood-vessels,  nerves,  marrow,  and 
the  like  in  different  bones.  The  unequal  amounts  of  organic  sub- 
stance found  in  the  compact  and  in  the  spongy  parts  of  the  same 
bone,  as  well  as  in  bones  at  different  periods  of  development  in  the 
same  animal,  depend  probably  upon  the  varying  quantities  of  these 
above-mentioned  formations.  Dentin,  which  is  comparatively  pure 
bony  structure,  contains  only  260-280  p.  m.  organic  substance,  and 
Hoppe-Seylee  '  therefore  thinks  it  probable  that  entirely  pure 
bony  substance  has  a  constant  composition  and  contains  only  about 
250  p.  m.  organic  substance.  The  question  whether  these  sub- 
stances are  chemically  combined  with  the  bone-earths  or  only 
intimately  mixed  has  not  been  decided. 

The  nutritive  fluids  wliicli  circulate  through  the  bones  have  not  been  iso- 
lated, and  we  only  know  that  they  contain  some  proteid  and  some  NaCl  and 
alkali  sulphate.  The  yellow  marrow  contains  chiefly  fat,  which  consists  of 
olein,  palmitin,  and  stearin.  Proteid  has  been  found  especially  in  the  so- 
called  red  marrow  of  the  spongy  bones  According  to  FOKREST  ^  the  proteid 
consists  of  a  globulin  coagulating  at  47-50°  C,  and  a  nucleo-albumin,  besides 
traces  of  albumin.  Besides  this  the  marrow  contains  so-called  extractive 
bodies,  such  as  lactic  acid,  hypoxanthin,  and  cholesterin,  but  mostly  bodies  of 
an  unknown  character. 

The  diverse  quantitative  composition  of  the  various  bones  of  the 
skeleton  depends  probably  on  the  varying  quantities  of  other  forma- 
tions, such  as  marrow,  blood-vessels,  etc.,  they  contain.  The  same 
reason  explains,  to  all  appearances,  the  larger  quantity  of  organic 
substance  in  the  spongy  parts  of  the  bones  as  compared  with  the 
more  compact  parts.  Schkodt  '  has  made  comparative  analyses  of 
different  parts  of  the  skeleton  of  the  same  animal  (dog),  and  has 
found  an  essential  difference.  The  quantity  of  water  in  the  fresh 
bones  varies  between  138  and  443  p.  m.  The  bones  of  the 
extremities  and  the  skull  contain  138-222,  the  vertebrae  168-443, 
and  the  ribs  324-356  p.  m.  water.  The  quantity  of  fat  varies 
between  13  and  269  p.  m.  The  largest  amount  of  fat,  256-269 
p.  m.,  is  found  in  the  long  tubular  bones,  while  only  13-175  p.  m. 

1  Physiol.  Chem..  S.  102-104. 
'-'  Journal  of  Physiol.,  Vol.  17. 

*  Landwirthsch.  Versuchsstat.,  Bd.  19.  Cited  from  Maly's  Jahresber., 
Bd.  6. 


COMPOSITION"^  OF  BONES.  351 

fat  is  found  in  the  small  short  bones.  The  quantity  of  organic 
substance,  calculated  from  fresh  bones,  was  150-300  p.  m.,  and  the 
quantity  of  mineral  substances  290-5G3  p.  m.  Contrary  to  the 
general  su^iposition  the  greatest  amount  of  bone-earths  was  not 
found  in  the  femur,  but  in  the  first  three  cervical  vertebrae.  In 
geese  the  largest  amount  of  bone-earth  was  found  in  the  humerus 
(Hiller'). 

We  do  not  possess  trustworthy  statements  in  regard  to  the  com- 
position of  bones  at  different  ages.  According  to  the  analyses  of 
E.  VoiT  °  of  bones  of  dogs  and  of  Brubacher  ^  of  bones  of 
children,  we  learn  that  the  skeleton  becomes  poorer  in  water  and 
richer  in  ash  with  increase  in  age.  Graffenberger  *  has  found 
in  rabbits  6|-T4^  years  old  that  the  bones  contained  only  140-170 
p.  m.  water,  while  the  bones  of  the  full-grown  rabbit  2-4  years  old 
contained  200-240  p.  m.  The  bones  of  old  rabbits  contain  more 
carbon  dioxide  and  less  calcium  phosiDhate. 

The  composition  of  bones  of  animals  of  different  species  is  but  little  known. 
The  bones  of  birds  contain,  as  a  rule,  somewhat  more  water  than  those  of 
mammalia,  and  the  bones  of  fishes  contain  the  largest  quantity  of  water.  The 
bones  of  fishes  and  amphibians  contain  a  greater  amount  of  organic  suiistance. 
The  bones  of  pachyderms  and  cetaceans  contain  a  large  proportion  of  calcium 
carbonate;  those  of  granivorous  birds  always  contain  silicic  acid.  The  bone- 
ash  of  amphibians  and  fishes  contains  sodium  sulphate.  The  bones  of  fishes 
seem  to  contain  more  soluble  salts  than  the  bones  of  other  animals. 

A  great  many  experiments  have  been  made  to  determine  the 
exchange  of  material  in  the  bones — for  instance,  with  food  rich  in 
lime  and  with  food  deficient  in  lime — but  the  results  have  always 
been  doubtful  or  contradictory.  The  attempts,  also,  to  substitute 
other  alkaline  earths  or  clay  for  the  lime  of  the  bones  have  given 
contradictory  results.  Weiske  ^  has  shown  by  experiments  on  not 
quite  full  grown  and  on  young  and  still  rapidly  growing  rabbits 
that  on  feeding  with  oats,  which  are  poor  in  acid  and  lime,  and 
simultaneously  magnesium  or  strontium  carbonate,  that  these  in 
part  pass  into  the  skeleton;  but  a  physiological  replacement  of  lime 
by  magnesiitm  or  strontium  is  not  to  be  expected.  On  the  admiuis- 
tration  of  madder  the  bones  of  the  animal  are  found  to  be  colored 

'  Landwirthsch.  Versuchsstat.,  Bd.  31.  Cited  from  Maly's  Jahresber., 
Bd.  14. 

'  Zeitschr.  f.  Biologie,  Bd.  16. 
«  Ihid.,  Bd.  27. 

*  Landwirthsch.  Versuchsstat.,  Bd.  39.  Cited  from  Maly's  Jahresber.,  Bd. 
21. 

*  Zeitschr.  f.  Biologie,  Bd.  31. 


352  TISSUES  OF  THE  CONNECTIVE  SUBSTANCE. 

red  after  a  few  days  or  weeks;  but  these  experiments  have  not  led 
to  any  positive  conclusion  in  regard  to  the  growth  or  metabolism  in 
the  bones. 

Under  pathological  conditions^  as  in  rachitis  and  softening  of 
the  bones,  an  ossein  has  been  found  which  does  not  give  any  typical 
gelatin  on  boiling  with  water.  Otherwise  pathological  conditions 
seem  to  affect  chiefly  the  quantitative  composition  of  the  bones,  and 
especially  the  relationship  between  the  organic  and  the  inorganic 
substance.  In  exostosis  and  osteosclerosis  the  quantity  of  organic 
substance  is  generally  increased.  Attempts  have  been  made  to 
produce  rachitis  in  animals  by  the  use  of  food  deficient  in  lime. 
From  experiments  on  fully  developed  animals  contradictory  results 
have  been  obtained.  In  young,  undeveloped  animals  Eewin" 
VoiT '  produced,  by  lack  of  lime-salts,  a  change  similar  to  rachitis. 
In  full-grown  animals  the  bones  were  changed  after  a  long  time 
because  of  the  lack  of  lime-salts  in  the  food,  but  did  not  become 
soft,  only  thinner  (osteoporosis).  The  experiments  of  removing  the 
lime-salts  from  the  bones  by  the  addition  of  lactic  acid  to  the  food 
have  led  to  no  positive  results  (HEiTZMAisrisr,^  Heiss,'  Baginskt^). 
Weiske,"  on  the  contrary,  has  shown,  by  administering  dilute  sul- 
phuric acid  or  monosodium  phosphate  with  the  food  (presupposing 
that  the  food  gave  no  alkaline  ash)  to  sheep  and  rabbits,  that  the 
quantity  of  mineral  bodies  in  the  bones  might  be  diminished.  A 
few  investigators  are  of  the  opinion  that  in  rachitis,  as  in  osteomala- 
cosis,  a  solution  of  the  lime-salts  by  means  of  lactic  acid  takes  place. 
This  was  suggested  by  the  fact  that  0.  Weber  and  C.  Schmidt  ^ 
found  lactic  acid  in  the  cyst-like,  altered  bony  substance  in 
osteomalacia. 

Well-known  investigators  have  disputed  the  possibility  of  the 
lime-salts  being  washed  from  the  bones  in  osteomalacosis  by  means 
of  lactic  acid.  They  have  given  special  prominence  to  the  fact  that 
the  lime-salts  held  in  solution  by  the  lactic  acid  must  be  deposited 
on  neutralization  of  the  acid  by  the  alkaline  blood.  This  objection 
is  not  very  important,  as  the  alkaline  stream  of  blood  has  the  prop- 

1  L.  c. 

2  Maly's  Jabresber.,  Bd.  3,  S.  229. 

3  Zeitscbr.  f.  Biologie,  Bd.  12. 
^  Vircbow's  Arcli. ,  Bd.  87. 

^  Landwirtbscb.  Versucbsstat.,  Bdd.  39  and  40.     Cited  from  Maly's  Jabres- 
ber., Bd.  22. 

^  Cited  from  Gorup  Besanez,  Lebrb.  d.  pbysiol.  Cbem. ,  4.  Aufi.,  S.  636. 


TOOTH  STRUCTURE.  SSS' 

erty  to  a  high  degree  of  holding  earthy  phosphates  in  solntiony 
which  can  be  easily  proved.  The  recent  investigations  of  Levy  ' 
contradict  the  statement  as  to  the  solution  of  the  lime-salts  by 
lactic  acid  in  osteomalacia.  He  has  found  that  the  normal  relation- 
ship 6P0^  :  lOCa  is  retained  in  all  parts  of  the  bones  in  osteoma- 
lacia, which  would  not  be  the  case  if  the  bone-earths  were  dissolved 
by  an  acid.  The  decrease  in  phosphate  occurs  in  the  same  quanti- 
tative relationship  as  the  carbonate,  and  according  to  Levy  in 
osteomalacia  the  exhaustion  of  the  bone  takes  place  by  a  decalcifica- 
tion in  which  one  molecule  of  phosphate  carbonate  after  the  other 
is  removed.    . 

In  rachitis  the  quantity  of  organic  matter  has  been  found  to  vary  between 
664  and  811  p.  m.  The  quantity  of  inorganic  substance  was  189-336  p.  m. 
These  figures  refer  to  the  dried  substance.  According  to  Brtxbacher'  rachitic 
bones  are  richer  in  water  than  the  bones  of  healthy  children,  aud  poorer  irk 
mineral  bodies,  especially  calcium  phosphate.  In  opposition  to  rachitis,  osteo- 
malacosis  is  often  characterized  by  the  considerable  amount  of  fat  in  the 
bones,  230-390  p.  m.;  but  as  a  rule  the  composition  varies  so  much  that  the 
analyses  are  of  little  value. 

The  tooth-structure  is  nearly  related,  from  a  chemical  stand- 
point, to  the  bony  structure. 

Of  the  tln-ee  chief  constituents  of  the  teeth,  dentin,  enamel, 
and  cement,  the  last-mentioned,  the  cement.^  is  to  be  considered  as 
true  bony  structure,  and  as  such  has  already  been  spoken  of  to  a, 
certain  extent.  Dentin  has  the  same  composition  as  the  bony  struc- 
ture, but  contains  somewhat  less  water.  The  organic  substance 
yields  gelatin  on  boiling;  but  the  dental  tubes  are  not  dissolved, 
therefore  they  cannot  consist  of  collagen.  In  dentin  200-28O' 
p.  m.  organic  substance  has  been  found.  Enamel  is  an  epitheliunT 
formation  containing  a  large  proportion  of  lime-salts.  The  orgauia 
substance  of  the  enamel  does  not  yield  any  gelatin.  Completely 
developed  enamel  contains  the  least  water,  the  greatest  quantity  of 
mineral  substances,  and  is  the  hardest  of  all  the  tissues  of  the  body. 
In  full-grown  animals  it  contains  hardly  any  water,  and  the  quan- 
tity of  organic  substance  amounts  to  only  20-40  p.  m.  The 
relative  amounts  of  calcium  and  phosphoric  acid  are,  according  to> 
the  analyses  of  Hoppe-Seyler,  about  the  same  as  in  bone-earths. 
The  quantity  of  chlorine  is  according  to  Hoppe-Seylbii  ^  remark- 
ably high,  0.3-0.5^. 

'  Zeitschr.  f.  physiol.  Chem.,  Bd.  19. 
"  Zeitschr.  f.  Biologie,  Bd.  27. 
'L.  c. 


S54  TISSUES  OF  THE  CONNECTIVE  SUBSTANCE. 

Carnot,  '  wlio  has  investigated  the  dentin  from  elepliants,  has  found  4.3 
p.  m.  calcium  fluoride  in  the  ash.  In  ivory  he  found  only  3.0  p.  m.  Dentin 
from  elephants  is  rich  in  magnesium  phosphate,  which  is  more  marked  in 
ivory. 

According  to  G-abriel  the  amount  of  fluorine  is  very  small  and 
amounts  to  1  p.  m.  in  ox-teeth.  It  is  greater  in  the  teeth  and 
enamel  than  in  the  bones.  According  to  GtABEIEL  a  strikingly 
small  portion  of  the  lime  of  the  enamel  is  replaced  by  magnesia, 
while  in  the  teeth  it  is  considerable. 

IV.  The  Fatty  Tissue. 

The  membranes  of  the  fat-ceils  withstand  the  action  of  alcohol 
and  ether.  They  are  not  dissolved  by  acetic  acid  nor  by  dilute 
mineral  acids,  but  are  dissolved  by  artificial  gastric  juice.  They 
may  possibly  consist  of  a  substance  closely  related  to  elastin.  The 
contents  of  the  fat-cells  are  fluid  during  life,  but  solidify  after 
death  and  become  more  or  less  solid,  depending  upon  the  character 
of  the  fats.  Besides  fat,  the  fat-cells  contain  a  yellow  pigment 
which  in  emaciation  does  not  disappear  so  rapidly  as  the  fat;  and 
this  is  the  reason  that  the  subcutaneous  cellular  tissue  of  an 
(emaciated  corpse  has  a  dark  orange-red  color.  The  cells  deficient 
in  or  nearly  free  from  fat,  which  remain  after  the  complete  dis- 
appearance of  the  latter,  seem  to  have  an  albuminous  protoplasm 
jich  in  water. 

The  less  water  the  fatty  tissue  contains  the  richer  it  is  in  fat. 
ScHULTZE  and  Keinecke  "  found  in  1000  parts : 

Water.  Membrane.  Fat. 

Fatty  tissue  of  oxen  99.7  16.6  883.7 

"       "  sheep 104.8  16.4  878.8 

"   pigs 64.4  13.6  922.0 

The  fat  contained  in  the  fat-cells  consists  chiefly  of  triglycerides 
of  stearic,  palmitic,  and  oleic  acids.  Besides  these,  especially  in  the 
less  solid  kinds  of  fats,  there  are  glycerides  of  caproic,  valerianic, 
and  other  fatty  acids  which  have  not  been  so  closely  investigated. 
In  all  animal  fats  there  are  besides  these,  as  Hofmaistk  '  has 
shown,  also  free,  non-volatile  fatty  acids,  although  in  very  small 
.amounts. 

The  more  solid  varieties  of  fat  of  the  adipose  tissue  consist,  as 

1  L.  c. 

2  Ann.  d.  Chem.  u.  Pharm.,  Bd,  142, 
»  Ludwig-Festschrift,  1874. 


FORMATION  OF  FAT.  355 

previously  stated  (Chapter  lY),  in  great  part  of  stearin  and 
palmitin,  while  the  less  solid  fats  have  a  greater  quantity  of  olein. 
Human  fat  is  as  a  rule  rich  in  olein.  The  fatty  tissue  of  cold- 
blooded animals  is  especially  rich  in  olein. 

The  properties  of  fats  in  general  and  the  three  most  important 
varieties  of  fat  have  already  been  treated  of  in  a  previous  chapter, 
hence  the  formation  of  the  adipose  tissue  is  of  chief  interest  at  this 
time. 

The  formation  of  fat  in  the  organism  may  occur  in  various  ways. 
The  fat  of  the  animal  body  may  consist  partly  of  absorbed  fat  of 
the  food  deposited  in  the  tissues  and  partly  of  fat  formed  in  the 
organism  from  other  bodies,  such  as  proteids  or  carbohydrates. 

That  the  fat  of  the  food  which  is  absorbed  in  the  intestinal  canal 
may  be  retained  by  the  tissues  has  been  shown  in  several  ways. 
Eadziejetvskt,'  Lebedeff,"  and  Mu]S"k  ^  have  fed  dogs  with 
various  fats,  such  as  linseed-oil,  mutton-tallow,  and  rape-seed-oil, 
and  have  afterwards  found  the  administered  fat  in  the  tissues. 
HoFiiAXX  ^  starved  dogs  until  they  appeared  to  have  lost  their  fat, 
and  then  fed  them  upon  large  quantities  of  fat  and  only  little  pro- 
teids. When  the  animals  were  killed  he  found  so  large  a  quantity 
of  fat  that  it  could  not  have  been  formed  from  the  administered 
proteids  alone,  but  the  greatest  part  must  have  been  derived  from 
the  fat  of  the  food.  Pettexkofee  and  Voit  ^  arrived  at  similar 
results  in  regard  to  the  behavior  of  the  absorbed  fats  in  the 
organism,  though  their  experiments  were  of  another  kind.  Munk  ' 
has  found  that  on  feeding  with  free  fatty  acids  these  are  deposited 
in  the  tissues,  not,  however,  as  such;  but  they  are  transformed  by 
synthesis  with  glycerin  into  neutral  fats  on  their  passage  from  the 
intestine  to  the  thoracic  duct.  According  to  Ewald,'  such  a 
synthesis  may  be  produced  by  the  mucous  membrane  of  the  intes- 
tine. 

Proteids  and  carbohydrates  are  considered  as  the  mother-sub- 
stance of  the  fats  formed  in  the  organism. 

The  formation  of  the  so-called  corpse- wax,  adipoceee,  which 

'  Vircliow's  Arch.,  Bd.  43. 

«  Pfiuger's  Arch.,  Bd.  31. 

'  Virchow's  Arch.,  Bd.  95. 

<  Zeitschr.  f.  Biologie,  Bd.  8. 

5  Ibid. ,  Bd.  9. 

«  Virchow's  Arch.,  Bd.  80. 

'  Du  Bois-Reymond's  Arch.,  1883. 


356  TISSUES  OF  TEE  CONNECTIVE  SUBSTANCE. 

consists  of  a  mixture  of  fatty  acids,  ammonia,  and  lime-soaps,  from 
parts  of  the  corpse  ricli  in  proteids,  is  sometimes  given  as  a  proof 
of  the  formation  of  fats  from  proteids.  The  provableness  of  this 
observation  has,  however,  been  disputed,  and  many  other  explana- 
tions of  the  formation  of  this  substance  have  been  offered.  Accord- 
ing to  the  recent  experiments  of  Keatter  ^  and  K.  B.  Lehmann  ^ 
it  seems  as  if  it  were  possible  by  experimental  means  to  convert 
animal  tissue  rich  in  proteids  (muscles)  into  adipocere  by  the  con- 
tinuous action  of  water.  Irrespective  of  this,  Salkowski^  has 
shown  recently  that  in  the  formation  of  adipocere  the  fat  itself 
takes  part  in  that  the  olein  decomposes  with  the  formation  of  solid 
fatty  acids;  still  it  must  be  considered  that  lower  organisms  un- 
doubtedly take  part  in  its  formation.  The  formation  of  adipocere 
as  a  proof  of  the  formation  of  fat  from  proteids  is  disputed  by 
many  investigators  for  this  and  other  reasons. 

Eatty  degeneration  is  another  proof  of  the  formation  of  fat  from 
proteids.  From  the  investigations  of  Bauer  *  on  dogs  and  Leo  ' 
on  frogs  we  must  admit  that  at  least  in  acute  poisoning  by  phos- 
phorus a  fatty  degeneration  with  the  formation  of  fat  from  proteids 
takes  place.  Still  investigators  are  not  unanimous  on  this  point, 
and  Pfluger  '  has  especially  raised  important  objections  to  these 
experiments. 

As  a  more  direct  proof  of  fat-formation  from  proteids  the  inves- 
tigations of  Pettenkoeer  and  Voit  ''  are  often  quoted.  These 
investigators  fed  dogs  with  large  quantities  of  meat  containing  the 
least  possible  proportion  of  fat,  and  found  all  of  the  nitrogen  in  the 
excreta,  but  only  a  part  of  the  carbon.  As  an  explanation  of  these 
conditions  it  has  been  assumed  that  the  proteid  of  the  organism 
splits  into  a  nitrogenized  and  a  non-nitrogenized  part,  the  former 
changing  into  the  nitrogenized  final  product,  urea,  the  other,  on 
the  contrary,  being  retained  in  the  organism  as  fat  (Pettexkofer 
and  Voit). 

Pfluger  *  has  arrived  at  the  following  conclusion  by  an  exhaus- 

1  Zeitsclir.  f.  Biologie,  Bd.  16. 

'  Sitzungsber.  d.  Wilrzb.  pliys.-med.  Gesellscli.,  1888. 
'  Zur  Kenntniss  der  Fettwacbsbildung.  Vircbow's  Festscbrift,  1891. 
4  Zeitscbr.  f.  Biologie,  Bd.  7. 
•>  Zeitscbr.  f.  pbysiol.  Cbem.,  Bd.  9. 

^  Pflliger's  Arcb.,  Bd.  51.     Tbis  contains  also  tbe  most  important  literature 
on  tbe  formation  of  fat  from  proteids. 

'  Liebig's  Annal.,  Suppl.  Bd.  2,  and  Zeitscbr.  f.  Biologie,  Bdd.  5.  6,  and  7. 
s  L.  0. 


FORMATION  OF  FAT.  35T 

tive  criticism  of  Pettexkofer  and  Yoit's  experiments  and  a 
careful  recalculation  of  their  balance-sheet,  namely,  that  tiiese  very 
meritorious  investigations,  which  were  continued  for  a  series  of 
years,  were  subject  to  such  great  defects  that  they  are  not  conclu- 
sive as  to  the  formation  of  fat  from  proteids.  He  especially 
emphasizes  the  fact  that  these  investigators  started  from  a  wrong 
assumption  as  to  the  elementary  composition  of  the  meat,  and  that 
the  quantity  of  nitrogen  assumed  by  them  was  too  low  and  the 
quantity  of  carbon  too  high.  The  relationship  of  nitrogen  to 
carbon  in  meat  poor  in  fat  was  assumed  by  Voit  to  be  as  1  :  3.68, 
while  according  to  Pfluger  it  is  1  :  3.22  for  fat-free  meat  after 
deducting  the  glycogen  and  1  :  3.28  according  to  Eubker  without 
deducting  the  glycogen.  On  recalculating  the  experiments  using 
these  coefficients,  Pfll'Ger  has  arrived  at  the  conclusion  that  the 
assumption  as  to  the  formation  of  fat  from  proteids  finds  no  sup- 
port in  these  experiments. 

Erwix  Yoit  '  on  recalculating  these  older  experiments  finds, 
contrary  to  the  above  objections,  that  at  least  in  a  few  cases  a 
deposit  of  carbon  originating  from  the  proteids  takes  place  in  the 
body.  He  has  also  made  new  experiments,  which  demonstrate, 
according  to  him,  that  the  administration  of  an  excess  of  meat 
causes  a  deposition  of  a  jmrt  of  the  carbon  as  a  non-nitrogenous 
combination  (probably  fat)  in  the  body. 

Another  more  direct  proof  for  the  formation  of  fat  from  pro- 
teids has  been  given  by  Hofmanx.'  He  experimented  with  fly- 
maggots.  A  number  of  these  were  killed  and  the  quantity  of  fat 
determined.  The  remainder  were  allowed  to  develop  in  blood 
whose  proportion  of  fat  had  been  previously  determined,  and  after 
a  certain  time  they  were  killed  and  analyzed.  He  found  in  them 
from  7  to  11  times  as  much  fat  as  in  the  maggots  first  analyzed  and 
the  blood  together  contained.  Pfluger^  has  made  the  objection 
that  a  considerable  number  of  lower  fungi  develop  in  the  blood 
under  these  conditions,  and  these  serve  as  food  for  the  maggots  and 
in  whose  cell-body  they  form  fats  and  carbohydrates  from  the  dif- 
ferent constituents  of  the  blood  and  their  decomposition  products. 

The  views  are  therefore  very  diverse  in  regard  to  the  conclu- 

'  Milnch.  med.  Wochenschr.,  1893,  No.  36.  Cited  from  Maly's  Jahresber., 
Bd.  33. 

«  Zeitschr.  f.  Biologie,  Bd.  8. 
3L.  c. 


358  TISSUES  OF  THE  CONNECTIVE  SUBSTANCE. 

siveness  of  these  experiments  as  to  the  formation  of  fat  from  pro- 
teids.  The  possibility  of  a  formation  of  fat  from  proteids  can 
hardly  be  disputed  by  any  investigator. 

If  we  admit  of  the  possibility  of  the  formation  of  fat  from  pro- 
teids, still  we  must  also  admit  that  we  do  not  know  anything  with 
positiveness  in  regard  to  the  chemical  processes  which  take  place. 
Drechsel,'  mindful  of  the  products  which  are  formed  by  the 
decomposition  of  proteids  with  barium  hydrate,  has  called  attention 
to  the  fact  that  the  proteid  molecule  probably  originally  contains 
no  radical  with  more  than  six  or  nine  carbon  atoms.  If  fat  is 
formed  from  proteid  in  the  animal  body,  then,  according  to 
Drechsel,  such  formation  is.  not  a  splitting  off  of  fat  from  the 
proteids,  but  rather  a  synthesis  from  primarily  formed  splitting 
products  of  proteids  which  are  deficient  in  carbon. 

The  formation  of  fat  from  carbohydrates  in  the  animal  body  was 
first  suggested  by  Liebig.  This  was  combated  for  some  time,  and 
until  lately  it  was  the  general  opinion  that  a  direct  formation  of 
fat  from  carbohydrates  had  not  been  proven,  but  also  that  it  was 
improbable.  The  undoubtedly  great  influence  of  the  carbohydrates 
on  the  formation  of  fat  as  observed  and  proven  by  Liebig  was 
explained  by  the  statement  that  the  carbohydrates  were  consumed 
instead  of  the  absorbed  fat  or  that  derived  from  the  proteids,  hence 
they  have  a  sparing  action  on  the  fat.  By  means  of  a  series  of 
nutrition  experiments  with  foods  especially  rich  in  carbohydrates, 
Lawes  and  Gilbert,^  Soxhlet,'  Tscherv^^inskt,^  Meissl  and 
Stromer'  (on  pigs),  B.  Schultze,'  Chaniewski,' E.  Voit  and 
C.  Lehmank  '  (on  geese),  I,  Mukk'  and  M.  Eubiter  "  (on  dogs) 
apparently  prove  that  a  direct  formation  of  fat  from  carbohydrates, 
does  actually  occur.  The  processes  by  which  this  formation  takes 
place  are  still  unknown.     As  the  carbohydrates  do  not  contain  as 

'  Ladenburg's  Handworterbucli  der  Cliem. ,  Bd.  3,  S.  543. 
«  Phil.  Transactions,  1859,  part  3. 
*  See  Maly's  Jaliresber.,  Bd.  11,  S.  51. 

■*  Landwirthscb.   Versucbsstat. ,  Bd.    29.      Cited  from  Maly's  Jahresber,, 
Bd.  13. 

6  Wien.  Sitzungsber.,  Bd.  88.  Abth.  3. 
6  Maly's  Jahresber.,  Bd.  11.  S.  47. 
'  Zeitschr.  f.  Biologie,  Bd.  20. 

8  See  C.  V.  Voit,  Sitzungsber.  d.  k.  bayer.  Akad.  d.  Wissensch.  1885. 

9  Virchow's  Arcb.,  Bd.  101. 

10  Zeitschr.  f.  Biologie,  Bd.  33. 


FORMATION  OF  FAT.  359 

complicated  carbon  chains  as  the  fats,  the  formation  of  fat  from 
carbohydrates  must  consist  of  a  synthesis,  in  which  the  group 
CHOH  is  converted  into  CH, ;  also  a  redaction  must  take  place. 

When  food  contains  an  excess  of  fat  the  superfluous  amount  is 
stored  up  in  the  fatty  tissue,  and  on  partaking  of  food  deficient  in 
fat  this  accumulation  is  quickly  exhausted.  There  is  perhaps  not 
one  of  the  various  tissues  that  decreases  so  much  in  starvation  a& 
the  fatty  tissue.  Tlae  organism,  then,  possesses  in  this  tissue  a 
depot  where  there  is  stored  during  proper  alimentation  a  nutritive 
substance  of  great  importance  in  the  development  of  heat  and  vital 
force,  which  substance,  on  insufficient  nutrition,  is  given  off  as  may 
be  needed.  On  account  of  their  low  conducting  power  the  fatty 
tissues  become  of  great  importance  in  regulating  the  loss  of  heat 
from  the  body.  They  also  serve  to  fill  cavities  and  as  a  protection 
and  support  to  certain  internal  organs. 


CHAPTER   XI. 

MUSCLE. 

Striated  Muscles. 

In  the  study  of  the  mnscles  the  chief  prohlem  for  physiological 
chemistry  is  to  isolate  their  different  morphological  elements  and  to 
investigate  each  element  separately.  By  reason  of  the  complicated 
structure  of  the  muscles  this  has  been  thus  far  almost  impossible, 
and  we  must  be  satisfied  at  the  present  time  with  a  few  micro- 
chemical  reactions  in  the  investigation  of  the  chemical  composition 
^of  the  muscular  fibres. 

Each  muscle-tube  or  muscle-fibre  consists  of  a  sheath,  the 
SARCOLEMMA,  which  secms  to  consist  of  a  substance  similar  to 
elastin,  and  a  contents  containing  a  large  proportion  of  proteids. 
This  last,  which  in  life  possesses  the  power  of  contractility,  has  in 
the  inactive  muscle  an  alkaline  reaction,  or,  more  correctly 
speaking,  an  amphoteric  reaction  with  a  predominating  action  on 
Ted  litmus-paper.  Rohmann  '  has  found  that  the  fresh,  inactive 
muscle  shows  an  alkaline  reaction  with  red  lacmoid  and  an 
acid  reaction  with  brown  turmeric.  Erom  the  behavior  of  these 
coloring  matters  with  various  acids  and  salts  he  concludes  that 
the  alkalinity  of  the  fresh  muscle  with  lacmoid  is  due  to  sodium 
l)icarbonate,  diphosphate,  and  probably  also  to  an  alkaline  combina- 
tion of  proteid  bodies,  and  the  acid  reaction  with  turmeric,  on  the 
contrary,  to  monophosphate  chiefly.  The  dead  muscle  has  an  acid 
reaction,  or  more  correctly  the  acidity  with  turmeric  increases  on 
the  decease  of  the  muscle  and  the  alkalinity  with  lacmoid  decreases. 
The  difference  depends  on  the  presence  of  a  larger  quantity  of 

1  The  various  statements  in  regard  to  the  reaction  of  the  muscles  and  the 
cause  thereof  are  disputed.  See  Rohmann,  Pfliiger's  Arch.,  Bdd.  50  and  55; 
HefEter,  Arch,  f .  exp.  Path.  u.  Pharm. ,  Bd.  31. 

360 


PROTEIDS   OF  THE  MUSCLE.  361 

monophosphate  in  the  dead  mnscle,  and  according  to  Rohmann 
free  lactic  acid  is  found  in  neither  the  one  case  nor  the  other. 

If  we  disregard  the  somewhat  disputed  statements  relative  to 
the  finer  structure  of  the  muscles,  we  can  differentiate  in  the 
striated  muscles  between  the  two  chief  components,  the  doubly- 
refracting — anisotropous — and  the  singly  refracting — isotropous — 
substance.  If  the  muscular  fibres  are  treated  with  reagents  which 
dissolve  proteids,  such  as  dilute  hydrochloric  acid,  soda  solution,  or 
gastric  juice,  they  swell  greatly  aud  break  up  into  "  Bowmax's 
disks.''''  By  the  action  of  alcohol,  chromic  acid,  boiling  water,  or 
in  general  such  reagents  as  cause  a  shrinking,  the  fibres  split  longi- 
tudinally into  fibrils;  and  this  behavior  shows  that  several  chemi- 
cally different  substances  of  various  sol  abilities  enter  into  the 
construction  of  the  muscular  fibres. 

The  proteid  myosin  is  generally  considered  as  the  chief  constit- 
uent of  the  diagonal  disks,  while  the  isotropous  substance  contains 
the  chief  mass  of  the  other  proteids  of  the  muscles  as  well  as  the 
chief  portion  of  the  extractives.  According  to  the  observations  of 
Danilewsky,'  and  recently  confirmed  by  J.  Holmgrex,'  myosin 
may  be  completely  extracted  from  the  muscle  without  changing  its 
structure,  by  means  of  a  5^  solution  of  ammonium  chloride. 
Danilewskt  claims  that  another  proteid-like  substance,  insoluble 
in  ammonium  chloride  aud  only  swelling  up  therein,  enters  essen- 
tially into  the  structure  of  the  muscles.  The  proteids,  which  form 
the  chief  part  of  the  solids  of  the  muscles,  are  of  the  greatest  im- 
jjortance. 

Proteids  of  the  Muscles. 

Like  the  blood  which  contains  a  fluid,  the  blood-plasma,  which 
spontaneously  coagulates,  separating  fibrin  and  yielding  blood- 
serum,  so  also  the  living  muscle  contains,  as  first  shown  by  Kuhxe,, 
a  spontaneously  coagulating  liquid,  the  muscle-plasma,  which 
coagulates  quickly,  separating  a  proteid  body,  myosin,  and  yielding 
also  a  serum.  That  liquid  which  is  obtained  by  pressing  the  living 
muscle  is  called  muscle-plas7na,  while  that  obtained  from  the  dead 
muscle  is  called  muscle-serum.  These  two  fluids  contain  different 
albuminous  bodies. 

Muscle-plasma  was  first  prepared  by  Kuhne  '  from  f rog-mus- 

'  Zeitschr.  f.  physiol.  Cliem.,  Bd.  7. 

»  Upsala  Lakaref.  Forli.,  Bd.  28,  and  Maly's  Jahresber.,  Bd.  23. 

»  Untersucliungeii  iiber  das  Protoplasma.     Leipzig,  1864. 


862  MUSCLE. 

cles,  and  later  by  Halliburton"'  according  to  the  same  method 
from  the  muscles  of  warm-blooded  animals,  especially  rabbits.  The 
principle  of  this  method  is  as  follows :  The  blood  is  removed  from 
the  muscles  immediately  after  the  death  of  the  animal  by  passing 
through  them  a  strongly  cooled  common-salt  solution  of  5-6  p.  m. 
Then  the  quickly  cut  muscles  are  immediately  thoroughly  frozen  so 
that  they  can  be  ground  in  this  state  to  a  fine  mass — "  muscle- 
snow."  This  pulp  is  strongly  pressed  in  the  cold,  and  the  liquid 
which  exudes,  the  muscle-plasma,  is  faintly  yellowish  in  color, 
alkaline,  and  spontaneously  but  slowly  coagulates  at  a  little  above 
0°  0.,  but  very  quickly  at  the  temperature  of  the  body.  In  the 
muscle-plasma  of  the  frog  the  reaction  does  not  change  immediately 
with  the  coagulation,  but  the  alkaline  reaction  is  gradually  changed 
into  an  acid  one.  The  liquid  which  exudes  from  the  clot,  the 
muscle-serum,  is  faintly  acid.  The  proteid  which  forms  the  clot 
has  been  called  myosin.  Besides  this  another  albuminous  body, 
musculin  or  paramyosinogen  (Halliburton),  is  found  in  the  clot. 

Myosin  was  first  discovered  by  Kuhne,  and  constitutes  the 
principal  mass  of  the  proteids  of  the  dead  muscle,  and  according  to 
a  few  investigators  it  forms  the  greatest  part  of  the  contractile 
protoplasm.  The  statements  as  to  the  occurrence  of  myosin  in 
other  organs  besides  the  muscles  require  further  proof.  The 
quantity  of  myosin  in  the  muscles  of  different  animals  varies, 
according  to  Danilewskt,"  between  30  and  110  p.  m. 

Myosin  is  a  globulin  whose  elementary  composition,  according 
to  Chittenden  and  Cummins,'  is,  on  an  average,  the  following: 
C  52.82,  H  7.11,  N  16.17,  S  1.27,  0  22.03^.  If  the  myosin 
separates  as  fibres,  or  if  a  myosin  solution  with  a  minimum  quantity 
of  alkali  is  allowed  to  evaporate  on  a  microscope-slide  to  a  gelat- 
inous mass,  doubly  refracting  myosin  may  be  obtained.  Myosin 
has  the  general  properties  of  the  globulins.  It  is  insoluble  in  water, 
but  soluble  in  dilute  saline  solutions  as  well  as  dilute  acids  or  alka- 
lies. It  is  completely  precipitated  by  saturating  with  NaCl,  also 
by  MgSO^,  in  a  solution  containing  94^  of  the  salt  with  its  water 
of  crystallization  (Halliburton').     Like  fibrinogen  it  coagulates 

*  Journal  of  Physiol.,  Vol.  8. 

*  Zeitscbr.  f.  pliysiol.  Chem.,  Bd.  7. 

*  Studies  from  the  Physiol.  Laboratory  of  Tale  College,  New  Haven,  vol.  3, 
p.  115. 

•»  Journal  of  Physiol.,  Vol.  8. 


MYOSIN  AND  MYOSIN  FERMENT.  363 

at  -\-  56°  C,  in  a  solution  containing  common  salt,  but  differs  from 
it  since  nnder  no  circumstances  can  it  be  converted  into  fibrin. 
The  coagulation  temperature,  according  to  Chittexden  and 
CuMMixs,  not  only  varies  for  myosin  of  different  origin,  but  also 
for  the  same  myosin  in  different  salt  solutions. 

Myosin  may  be  prepared  in  tlie  following  way,  as  suggested  by 
Hallibuktox:  The  muscle  is  first  extracted  by  a  6%  magnesium, 
sulphate  solution.  The  filtered  extract  is  then  treated  with  mag- 
nesium sulphate  in  substance  until  100  c.  c.  of  the  liquid  contains 
about  50  grms.  of  the  salt.  The  so-called  paramyosinogen  or 
musculin  separates.  The  filtered  liquid  is  then  treated  with  mag- 
nesium sulphate  until  each  100  c.  c.  of  the  liquid  holds  94  grms.  of 
the  salt  in  solution.  The  myosin  which  now  separates  is  filtered 
off,  dissolved  in  water  by  aid  of  the  retained  salt,  precipitated  by 
diluting  with  water,  and,  when  necessary,  purified  by  redissolving 
in  dilute-salt  solution  and  precipitating  wnth  water. 

The  older  and  perhaps  the  usual  method  of  preparation  consists, 
according  to  Danilewsky,'  in  extracting  the  muscle  with  a  5-10^ 
ammonium-chloride  solution,  precipitating  the  myosin  from  the 
filtrate  by  strongly  diluting  with  water,  redissolving  the  precipitate 
in  ammonium-chloride  solution,  and  the  myosin  obtained  from  this 
solution  is  either  reprecipitated  by  dilating  with  water  or  by 
removing  the  salt  by  dialysis. 

As  the  coagulation  of  the  blood-plasma  is  considered  by  most 
investigators  as  an  enzymotic  process,  so  certain  observations  seem 
to  show  that  the  coagulation  of  the  muscle-plasma  is  an  analogous 
process.  From  muscles  which  had  been  kept  for  a  long  time  in 
alcohol  Halliburton  obtained,  by  extracting  the  mass  with  water, 
a  soluble  substance  contaminated  with  albumose  which,  although 
not  identical  with  fibrin-ferment,  had  the  property  of  accelerating 
the  coagulation  of  the  muscle-plasma.  This  substance  he  called 
^^  myosin- ferment.''''  It  has  been  shown  by  the  investigations  of 
Cavazzani,''  that  the  lime-salts  are  of  importance  in  the  coagula- 
tion of  the  muscle-plasma  as  well  as  in  that  of  the  blood. 

As  in  the  blood-plasma  we  have  a  mother-substance  of  fibrin, 
fibrinogen,  so  also  it  is  considered  that  in  the  muscle-plasma  we 
have  a  mother-substance  of  myosin,  myosinogen.  This  body  has 
not  thus  far  been  isolated  with  certainty.  Halliburton  found 
that  a  solution  of  purified  myosin  in  dilute-salt  solution  [5% 
MgSOJ,   and  sufficiently    diluted  with  water,   coagulates   after  a 

'  Zeitscbr.  f.  pliysiol.  Cliem.,  Bd.  5,  S.  158. 
>  Maly's  Jahresber.,  Bd.  23,  S.  333. 


:3Gi  MUSCLE. 

certain  time,  and  at  the  same  time  becomes  acid  and  a  typical 
myosin-clot  separates.  This  coagulation,  which  is  accelerated  by 
warming  or  by  the  addition  of  myosin-ferment,  is,  according  to 
HALLiBURTOisr,  a  process  analogous  to  the  coagulation  of  the 
muscle-plasma.  According  to  this  same  investigator,  myosin  when 
dissolved  in  water  by  the  aid  of  a  neutral  salt  is  reconverted  into 
myosinogen,  while  after  diluting  with  water  myosin  is  again  pro- 
duced from  the  myosinogen.  These  observations  may,  however,  be 
■explained  in  other  ways.  In  these  cases  the  separation  of  the 
myosin  is  evidently  closely  connected  with  the  liquid  becoming  acid, 
while  the  separation  of  myosin  from  the  muscle-plasma,  at  least 
from  the  muscle-plasma  of  the  frog,  is  independent  of  this  acidity, 
for  it  may  take  place  before  the  liquid  becomes  acid.  The  mother- 
substance  of  myosin  and  the  chemical  processes  of  the  myosin 
coagulation  are  questions  which  mnst  not  be  considered  as  settled. 

Musculin,  called  PARAMYOSi]sroGE]sr  by  HALLiBURTOiir,  is  a 
globulin  which  is  characterized  by  its  low  coagulation  temperature, 
about  +  47°  C,  which  may  vary  in  different  species  of  animals 
|_^  45°  in  frogs,  +  51°  C.  in  birds).  It  is  more  easily  dissolved 
than  myosin  by  NaCl  or  MgSO,  (salt  containing  50^  water  of 
crystallization).  Musculin  is  separated  simultaneously  with  myosin 
in  the  coagulation  of  the  muscle-plasma,  and  it  is  therefore  found 
in  the  clot.  A  solution  which  contains  musculin  and  no  myosin 
does  not  coagulate  on  the  addition  of  the  myosin-ferment  (Halli- 
burton). If  the  dead  muscle  is  extracted  with  water,  the  musculin 
passes  in  part  into  solution.  The  musculin  may  be  isolated  by 
fractional  precipitation  with  magnesium  sulphate  (50  grms.  to  each 
100  c.  c.  liquid),  and  may  be  identified  by  its  low  coagulation  tem- 
perature. 

MyoglohuUn.  After  the  separation  of  the  musculin  and  the 
myosin  from  the  salt  extract  of  the  muscle  by  means  of  MgSO^  the 
myoglobulin  may  be  precipitated  by  saturating  the  filtrate  with 
the  salt.  It  is  similar  to  serglobulin,  but  coagulates  at  +  63°  C. 
(Halliburton).  Myodlhumin  or  muscle-albumin,  seems  to  be 
identical  with  seralbumin  (seralbumin  a,  according  to  Hallibur- 
ton), and  is  prepared  according  to  the  same  method.  Myoalhumose 
(a  deuteroalbumose)  is  found  in  small  quantities  in  the  muscles,  and 
may  be  obtained  by  extracting  with  water  the  finely  divided  mass 
of  muscle  which  has  previously  been  coagulated  by  keeping  in 
alcohol  for  a  long  time  (Halliburton). 


MUSCLE  PIGMENTS.  365 

After  the  complete  removal  from  the  muscle  of  all  proteid  bodies 
which  are  soluble  in  water  and  ammonium  chloride,  Dais'ILEWSKY  ' 
claims  that  an  insoluble  proteid  remains  which  only  swells  in 
ammonium-chloride  solution  and  which  forms  with  the  other  insolu- 
ble constituents  of  the  muscular  fibre  the  ^'  mnsde-stroma.''* 
According  to  Danilewskt,  the  amount  of  such  stroma  substance 
is  connected  with  the  muscle  activity.  He  maintains  that  the 
muscles  contain  a  greater  amount  of  this  substance,  compared  with 
the  myosin  present,  when  the  muscles  are  quickly  contracted  and 
relaxed. 

According  to  J.  Holmgren  '  this  stroma  substance  does  not 
belong  to  either  the  nucleoalbnmin  or  the  nucleoproteid  group.  It 
is  not  a  glycoproteid,  as  it  does  not  yield  a  reducing  substance 
when  boiled  with  dilute  mineral  acids.  It  is  very  similar  to  coagu- 
lated proteids  and  dissolves  in  dilute  alkalies,  forming  an  albuminate. 
The  elementary  composition  of  this  substance  is  nearly  the  same 
as  that  of  myosin. 

Muscle-syntonin,  which  may  be  obtained  by  extracting  the 
muscles  with  hydrochloric  acid  of  1  p.  m.,  and  which,  according  to 
K.  MoRNER,  is  less  soluble  and  has  a  greater  aptitude  to  precipitate 
than  other  acid  albumins,  seems  not  to  occur  preformed  in  the 
muscles. 

Muscle-pigments.  There  is  no  question  that  the  red  color  of 
the  muscles  even  when  completely  freed  from  blood  depends  in  part 
on  haemoglobin,  though  it  is  contested  by  many.  MacMuxn  * 
claims  that  the  muscles  contain  also  another  coloring  substance 
wiiicli  is  closely  allied  to  the  blood-pigments  and  whose  spectrum  is 
very  similar  to  that  of  haemochromogen.  This  coloring  matter  has 
been  called  myohcBmatin.  According  to  Levy  ^  this  myohsematin 
is  nothing  but  haemochromogen,  which  is  produced  from  oxyhaemo- 
globin  by  decomposition  and  reduction.  Nevertheless  MacMuxx  * 
still  adheres  to  his  view  that  myohaematin  is  an  independent  color- 
ing substance,  and  in  support  of  his  opinion  he  adduces  the  fact  that 
myohfematin  is  found  also  in  the  muscles  of  insects  in  which  no 
haemoglobin  occurs. 

'  Zeitschr.  f.  Physiol.,  Bd.  7. 

»Upsala  Lakaref.  Fork.,  Bd.  38,  and  Maly's  Jaliresber.,  Bd.  23. 

3  Phil.  Trans,  of  the  R07.  Soc,  1886,  Part  1,  and  Journal  of  Physiol., 
Vol.  8. 

*  Zeitschr.  f.  physiol.  Chem.,  Bd.  13. 

^  Ihid.,  Bd.  13.  S.  497. 


366  MUSCLE. 

The  reddish-yellow  coloring  matter  of  the  muscles  of  the  salmon  has  been 
little  studied.  Traces  of  enzymes,  such  as  pepsin  and  diastatic  enzymes,  have 
been  found  in  them.  The  so-called  "  mj^osin-ferment,"  and  probably  an 
enzyme  producing  lactic-acid  fermentation,  are  also  found  in  these  muscles. 

Extractive  Bodies  of  the  Muscles. 

The  nitrogenous  extractives  consist  chiefly  of  creatin,   on  an 

average  of  2-4  p.  m.,  in  the  fresh  muscles  containing  water,  also 

the  xanthin  bases,  Tiypoxantliin  and  xantliin.,  besides  guanin  and 

carnin.     The   average    quantities    of    hypoxanthin,    xanthin,   and 

guanin  in  1000  parts  of  the  dried  substance  of  the  muscles  of  oxen 

are,  according  to  Kossel,'  respectively  2.30,  0.53,  and  0.20  grms., 

and  in  the  embryonic  ox-muscles  respectively  3.59,  1.11,  and  4.12 

grms. 

Besides  these  we  must  also  consider  as  an  extractive  body  the  syrupy  inosinic 
acirf  (C10H14N4O1]),  of  which  only  traces  are  found  in  the  muscles  of  certain 
animals  This  acid  was  first  prepared  by  Liebig,^  but  not  closely  studied. 
LiMPRiCHT^  has  found  another  in  the  flesh  of  certain  cyprindea,  namely,  the 
nitrogenized  protic  acid,  and  !;iegpkied^  has  recently  found  another  acid, 
carnic  acid,  which  will  be  treated  of  below.  Uric  acid,  urea,  taurin,  and 
leucin  are  found  as  traces  in  the  muscles. in  certain  cases  only,  of  a  few  species 
of  animals.  In  regard  to  the  amount  of  these  different  extractives  in  the 
muscles,  Krukenbekg  and  Wagner  ^  have  shown  that  it  varies  greatly  in 
different  animals.  A  large  quantity  of  urea  is  found  in  the  muscles  of  the 
shark  and  ray  ;  uric  acid  is  found  in  alligators  ;  taurin  in  cephalopoda  ;  glyco- 
coll  in  mollusks,  pecten  irradians  ;  and  creatinin  in  luvarus  imperialis,  etc., 
etc.  The  statements  are  very  contradictory  in  regard  to  the  occurrence  of  urea 
in  the  muscles  of  higher  animals.  According  to  the  recent  investigations  of 
Kaufmann  *  urea  is  a  regular  constituent  of  the  muscles,  the  quantity  in 
fresh  muscles  containing  water  being  0.27-0  7  p.  m. 

The  xanthin  bases,  with  the  exception  of  carnin,  have  been 
treated  on  pages  102-108,  and  therefore  among  the  extractive 
bodies  we  will  first  consider  the  creatin. 

Creatin,  C^HgNgO^  +  H^O  or  methylguanidin" -acetic  acid, 
NH:C(NHJ.N(CH3).CH,.C00H  +  H,0,  occurs  in  the  muscles 
of  vertebrate  animals  in  variable  amounts  in  different  species;  the 
largest  quantity  is  found  in  birds.  It  is  also  found  in  the  brain, 
blood,  transudations,  and  the  amniotic  fluid.  Creatin  may  be  pre- 
pared synthetically  from  cyanamid  and  sarcosin  (metbylglycocoll). 
On  boiling  with  baryta-water  it  decomposes,  with  the  addition  of 
water,    and   yields   urea,    sarcosin,    and    certain    other  products. 

'  Zeitschr.  f.  physiol.  Chem.  Bd.  8,  S.  408. 

*  Annal.  d.  Chem.  u.  Pharm.,  Bd.  62  (1847). 
^  Ibid..  Bd.  \Z1. 

*  Ber,  d.  k.  sac-hs.  Gesellsch.  d.  Wiss.,  Math.-phys.  Klasse,  1893. 
5  Zeitschr.  f.  Biologie,  Bd.  21. 

'  Arch,  de  Physiol.,  (5)  Tome  6. 


CREATIN  AND   CARNIN.  367 

Because  of  this  behavior  several  investigators  consider  creatin  as  a 
step  in  the  formation  of  urea  in  the  organism.  On  boiling  with 
acids  creatin  is  easily  converted,  with  the  elimination  of  water,  into 
creatinin,  C^H^lSTgO,  which  occurs  in  urine,  and  which  has  also  been 
found  in  the  muscles  of  the  dog  by  Monari  '  (see  Chapter  XV). 

According  to  St.  Johnson  ^  no  creatin  occurs  in  the  fresh  flesh  of  oxen,  but 
a  creatinin,  differing  from  that  found  in  urine.  Muscle-creatin  is  produced 
therefrom  by  bacterial  action. 

Creatin  crystallizes  in  hard,  colorless,  monoclinic  prisms  which 
lose  their  water  of  crystallization  at  100°  C.  It  dissolves  in  74 
parts  of  water  at  the  ordinary  temperature  and  9410  parts  absolute 
alcohol.  It  dissolves  more  easily  with  the  aid  of  heat.  Its  watery 
solution  has  a  neutral  reaction.  Creatin  is  not  dissolved  by  ether. 
If  a  creatin  solution  is  boiled  with  precipitated  mercuric  oxide,  this 
is  reduced,  especially  in  the  presence  of  alkali,  to  mercury  and 
oxalic  acid,  and  the  disgusting-smelling  methyl uramin  (methyl- 
guanidin)  is  developed.  A  solution  of  creatin  in  water  is  not  pre- 
cipitated by  basic  lead  acetate,  but  gives  a  white,  flaky  precipitate 
with  mercurous  nitrate  if  the  acid  reaction  is  neutralized.  When 
boiled  for  an  hour  with  dilute  hydrochloric  acid  creatin  is  converted 
into  creatinin,  and  may  be  identified  by  its  reactions. 

The  preparation  and  detection  of  creatin  is  best  performed  by 
the  following  method  of  JSTeubauer,'  which  was  first  used  in  the 
preparation  of  creatin  from  muscles:  Mnely  cut  flesh  is  extracted 
with  an  equal  weight  of  water  at  +  55°  to  60°  C.  for  10-15 
minutes,  pressed  and  extracted  again  with  water.  The  proteids  are 
removed  from  the  united  extracts  as  far  as  possible  by  coagulation 
at  boiling  heat,  the  filtrate  precipitated  by  the  careful  addition  of 
basic  lead  acetate,  the  lead  removed  from  this  filtrate  by  H  S  and 
carefully  concentrated  to  a  small  volume.  The  creatin,  which 
crysrallizes  in  a  few  days,  is  collected  on  a  filter,  washed  with  alcoliol 
of  88^  and  purified,  when  necessary,  by  recrystallization.  The 
quantitative  estimation  of  creatin  is  performed  according  to  the 
same  method. 

Carnin,  C,H^N,03  +  H,0,  is  one  of  the  substances  found  by 
Weidel  *  in  American  meat  extract.  It  has  also  been  found  by 
Krukenbeeg  and  Wagner  '  in  frog-muscles  and  in  the  flesh  of 

'  Maly's  Jahresber.,  Bd.  19,  S.  296. 

*  Proc.  Roy.  Soc.     Cited  from  Maly's  Jahresber.,  Bd.  22. 
3  Zeitschr.  f.  anal.  Chem.,  Bdd.  2  and  6. 

^Annal.  d.  Chem.  u.  Pharm.,  BJ.  158. 

*  Sitzungsber.  d.  WUrz.  phys.-med.  Gesellsch.,  1883. 


368  MUSCLE. 

fishes,  and  by  Potjchet  '  in  the  urine.     Carnin  may  be  transformed 
into  hypoxanthin  by  oxidation. 

Carnin  has  been  obtained  as  a  white  crystalline  mass.  It  dis- 
solves with  difficulty  in  cold  water,  but  dissolves  easily  in  warm. 
It  is  insoluble  in  alcohol  and  ether.  It  dissolves  in  warm  hydro- 
chloric acid  and  yields  a  salt,  crystallizing  in  shining  needles,  which 
gives  a  double  combination  with  platinum  chloride.  Its  watery 
solution  is  precipitated  by  silver  nitrate,  but  this  precipitate  is 
neither  dissolved  by  ammonia  nor  by  warm  nitric  acid.  Carnin 
does  not  give  the  so-called  Weidel's  xanthin  reaction.  Its  watery 
solution  is  precipitated  by  basic  lead  acetate;  still  the  lead  combi- 
nations may  be  dissolved  on  boiling. 

Carnin  is  prepared  by  the  following  method:  The  meat  extract 
diluted  with  water  is  completely  precipitated  by  baryta- water.  The 
filtrate  is  precipitated  by  basic  lead  acetate,  the  lead  precipitate 
boiled  with  water,  filtered  while  hot,  and  sulpharetted  hydrogen 
passed  through  the  filtrate.  Eemove  the  lead  sulphide  from  the 
filtrate  and  concentrate  strongly.  The  concentrated  solution  is  now 
completely  precipitated  with  silver  nitrate,  the  precipitate  washed 
free  from  silver  chloride  by  ammonia,  and  the  carnin  silver  oxide 
suspended  in  water  and  treated  with  sulphuretted  hydrogen. 

Carnic  Acid  is  the  name  given  by  Siegfried  '  to  tlie  acid  isolated  by  him 
from  meat  extract  and  from  the  watery  extract  of  the  muscles.  It  has  the 
formula  C10H15N3O5.  It  is  readily  soluble  in  water,  and  its  warm  alcoholic 
solution  deposits  undefined  crystalline  surfaces  on  cooling.  It  gives  several 
crystalline  salts,  amongst  which  the  silver  salt,  with  42.6^  silver,  is  of  the 
greatest  importance.  Carnic  acid  gives  the  biuret  test,  but  not  Millon's  reac- 
tion, and  it  is  so  very  similar  to  antipeptone  (from  which  it  differs  by  not  hav- 
ing sulphur  in  the  molecule)  that  Siegfried  considers  it  identical  therewith. 
Sulphuretted  hydrogen  is  oxidized  by  carnic  acid  in  the  presence  of  air  into 
thiosulphuric  acid  ;  with  hydrochloric  acid  it  yields,  by  addition,  a  very  solid 
combination,  and  with  phosphoric  acid  it  forms  an  acid,  phosphocarnic  acid. 
This  last-mentioned  acid  forms  soluble  salts  with  calcium  and  magnesium,  and 
Siegfried  considers  carnic  acid  as  a  substance  which  simultaneously  transports 
phosphoric  acid,  lime,  magnesia,  and  also  iron  in  the  organism.  Phosphocar- 
nic acid  gives  also  a  combination  with  iron,  which  is  soluble  in  alkalies  and 
alkali  carbonates.  Siegfried  calls  such  a  combination  carniferrin.  Carnic 
acid  occurs  in  muscle  extracts  as  phosphocarnic  acid  ;  but  as  no  true  peptone 
has  been  heretofore  detected  in  fresh  muscles,  it  is  a  question  whether  car- 
nic acid  is  a  physiological  constituent  of  muscles  or  only  a  laboration  product. 
According  to  Siegfried^  phosphocarnic  acid  yields  carnic  acid  (antipeptone), 

'  Cited  from  Neubauer-Hlippert,  Analyse  des  Harns,  10.  Aufl.,  S.  335 
'  Du  Bois-Eeymond's  Arch.,  Physiol.  Abth.,  1894. 
*  Ber.  d.  deutsch.  chem.  Gesellsch. ,  Bd.  28. 


INOSIT.  369 

phosphoric  acid,  and  a  carbohydrate  as  cleavage  products.  It  therefore  stands 
iu  close  relationship  to  the  uucleins,  and  Siegfried  suggests  the  n&me  paranu- 
cleon,  to  show  that  on  cleavage  they  yield  a  peptone  substance,  and  not  proteid 
like  the  paranucleins. 

Carnic  acid  is  best  prepared  by  precipitating  the  extract,  which  has  been 
freed  from  proteid,  by  baryta- water  at  the  ordinary  temperature,  being  careful 
not  to  add  an  excess.  The  filtrate  contains  the  barium  salt  of  the  phosphocar- 
nic  acid,  which  is  precipitated  as  carniferrin  by  ferric  chloride  at  the  boiling 
temperature.  This  carniferrin  is  decomposed  by  barium  hydrate  at  50°  C. 
The  excess  of  barium  is  removed  from  the  filtrate  by  sulphuric  acid,  filtered, 
concentrated,  and  the  carnic  acid  precipitated  by  alcohol.  The  acid  is  purified 
by  repeated  precipitation  with  alcohol. 

We  must  also  include  among  the  nitrogenous  extractives  those 
bodies  which  were  first  discovered  by  Gautier'  and  which  occur 
only  in  very  small  quantities,  namely,  the  leucomaines,  xantho- 
creatinin,  C^H^^N^O,  crnsocreatmin^  O^H^N^O,  amphicreatinin,. 
0^11,^^,0^,  and  psendoxa7ithin,  C/H^N^O. 

In  the  analysis  of  meat  and  for  the  detection  and  separation  of 
the  various  extractive  bodies  of  the  same  we  make  use  of  the  syste- 
matic method  as  suggested  by  Gautier,"  for  details  of  which  we 
mast  refer  the  reader  to  the  original  article. 

The  non-nitrogenous  extractive  bodies  of  the  muscles  are  inosit, 

glycogeri,  dextrose,  and  lactic  acid. 

Inosit,  C,H,^0„  +  H^O.  This  body,  discovered  by  Scherer, 
is  not  a  carbohydrate,  but  belongs  to  the  aromatic  series  and  seems 
to  be  hexahydroxybenzol  (Maquenne').  With  hydriodic  acid  it 
yields  benzol  and  tri-iodophenol.  Inosit  is  found  in  the  muscles, 
liver,  spleen,  kidneys,  suprarenal  cavity,  lungs,  brain,  testicles, 
and  in  the  urine  in  pathological  cases,  and  as  traces  in  normal 
urine.  It  is  found  very  widely  distributed  in  the  vegetable  king- 
dom, especially  in  unripe  fruits  and  in  green  beans  {phaseolus  vtil- 
garis),  and  therefore  it  is  also  called  phaseomannit. 

Iiiosit  crystallizes  in  large,  colorless,  rhombic  crystals  of  the 
monoclinic  system,  or,  if  not  pure  and  if  only  a  small  quantity 
crystallizes,  it  forms  groups  of  fine  crystals  similar  to  cauliflower. 
It  loses  its  water  of  crystallization  at  110°  C,  also  if  exposed  to  the 
air  for  a  long  time.  Such  exposed  crystals  are  non-transparent  and 
milk-white.     The  crystals  melt  at  217°  C.     Inosit  dissolves  in  7.5 

>  Maly's  Jahresber.,  Bd.  16,  S.  523. 

■^  lUd.,  Bd.  32,  S.335. 

3  Bull,  de  la  Soc.  chim.  (2),  Tome  47  and  48  ;  Comp.  rend..  Tome  104. 


370  MUSCLE. 

parts  of  water  at  ordinary  temperature,  and  the  solution  has  a 
sweetish  taste.  It  is  insoluble  in  strong  alcohol  and  in  ether.  It 
dissolves  copper  oxyhydrate  in  alkaline  solutions,  but  does  not 
reduce  on  boiling.  It  gives  negative  results  with  Moore's  test  and 
with  Bottger-Almen's  bismuth  test.  It  does  not  ferment  with 
beer-yeast,  but  may  undergo  lactic-  and  butyric-acid  fermentation. 
The  lactic  acid  formed  thereby  is  sarcolactic  acid  according  to 
HiLGER,'  and  fermentation  lactic  acid  according  to  Vohl.'^  Inosit 
is  oxidized  into  rhodizonic  acid  by  an  excess  of  nitric  acid,  and  the 
following  reactions  depend  upon  this  behavior : 

If  inosit  is  evaporated  to  dryness  on  platinum-foil  with  nitric 
acid  and  the  residue  treated  with  ammonia  and  a  drop  of  calcium- 
chloride  solution,  and  carefully  re-evaporated  to  dryness,  a  beautiful 
rose-red  residue  is  obtained  (Scherer's  inosit  test).  If  we  evapo- 
rate an  inosit  solution  to  incipient  dryness  and  moisten  the  residue 
with  a  little  mercuric-nitrate  solution,  we  obtain  a  yellowish  residue 
on  drying,  which  becomes  a  beautiful  red  on  strongly  heating. 
The  coloration  disappears  on  cooling,  but  it  reappears  on  gently 
warming  (GtALLOIs's  inosit  test). 

To  prepare  inosit  from  a  liquid  or  from  a  watery  extract  of  a 
tissue,  the  proteids  are  first  removed  by  coagulating  at  boiling  heat. 
T^e  filtrate  is  precipitated  by  sugar  of  lead,  this  filtrate  boiled  with 
basic  lead  acetate  and  allowed  to  stand  24-48  hours.  The  precipi- 
tate thus  obtained,  which  contains  all  the  inosit,  is  decomposed  in 
water  by  H^S.  The  filtrate  is  strongly  concentrated,  treated  with 
2-4  vols,  hot  alcohol,  and  the  liquid  removed  as  soon  as  possible 
from  the  tough  or  flaky  masses  which  ordinarily  separate.  If  no 
crystals  separate  from  the  liquid  within  24  hours,  then  treat  with 
ether  until  the  liquid  has  a  milky  appearance  and  allow  it  to  stand. 
In  the  presence  of  a  sufficient  quantity  of  ether,  crystals  of  inosit 
separate  within  24  hours.  The  crystals  thus  obtained,  as  also  those 
which  are  obtained  from  the  alcoholic  solution  directly,  are  recrys- 
tallized  by  redissolving  in  very  little  boiling  water  and  the  addition 
of  3-4  vols,  alcohol. 

Glycogen  is  a  constant  constituent  of  the  living  muscle,  while 
it  may  be  absent  in  the  dead  muscle.  The  quantity  of  glycogen 
varies  in  the  different  muscles  of  the  same  animal.  Bohm  '  found 
10  p.  m.  glycogen  in  the  muscles  of  cats,  and  moreover  he  found  a 
greater  amount  in  the  muscles  of  the  extremities  than  in  those  of 

»  Annal.  d.  Chem.  u.  Pharm.,  Bd.  160. 
*  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  9. 
3  Pfluger's  Arch.,  Bd.  23,  S.  44. 


LACTIC  ACIDS.  371 

the  ramp.  The  food  also  has  a  great  influence.  Bonn  foand 
1-4  p,  m,  glycogen  iu  the  muscles  of  fasting  animals  and  7-10 
p.  m.  after  partaking  of  food.  Luchsingek  maintains  an  opinion, 
formerly  generally  accepted,  that  in  starvation,  or  if  there  is  a  lack 
of  carbohydrates  in  the  food,  glycogen  disappears  more  quickly 
from  the  muscles  than  from  the  liver;  but  according  to  Aldehoff 
exactly  the  reverse  takes  place.  The  glycogen  disappears  more 
quickly  in  starvation  from  the  liver  than  from  the  muscles,  not 
only  in  hens,  as  observed  by  Weiss,  but  also  in  other  animals,  such 
as  the  pigeon,  rabbit,  cat,  and  horse.' 

Muscle-sugar,  of  which  traces  only  occur  in  the  living  muscle 
and  which  is  probably  formed  after  the  death  of  the  muscle  from 
the  muscle-glycogen,  is,  according  to  the  investigations  of  Panor- 
MOFF,'  probably  dextrose.  As  an  intermediate  step  in  this  sugar- 
formation  we  must  mention  dextrin,  which  is  sometimes  found  in 
the  muscles.  Perhaps  this  dextrin  has  been  confounded  with 
glycogen. 

Lactic  Acids.  Of  the  oxypropionic  acids  with  the  formula 
C.H.O,  there  is  one,  hydracrylic  acid,  CH,(OH).CH,.COOH, 
which  is  not  found  in  the  animal  body  and  therefore  has  no  physio- 
logical chemical  interest.  Indeed  only  ar-oxypropionic  acid  or 
ethylidene  lactic  acid,  CH3.CH(0H).C00H,  of  which  we  have 
three  physical  isomers,  is  of  importance.  These  three  ethylidene 
lactic  acids  are  the  ordinary,  optically  inactive  fermentation  lac- 
tic ACID,  the  dextrorotatory  paralactic  or  sarcolactic  acid, 
and  the  l^volactic  acid  obtained  by  Schardinger  '  by  the  fer- 
mentation of  cane-sugar  by  means  of  a  special  bacillus.  This  Isevo- 
lactic  acid  has  also  been  detected  by  Blachstein  *  in  the  culture 
of  Gaffkt's  typhoid  bacillns  in  a  solution  of  sugar  and  peptone. 

ThQ  fermentation  lactic  acid,  which  is  formed  from  milk-sugar 
by  allowing  milk  to  sour  and  by  the  acid  fermentation  of  other 
carbohydrates,  is  considered  to  exist  in  small  quantities  in  the 
muscles  (Heixtz  '),  in  the  gray  matter  of  the  brain  (Gscheidlen  '), 
and  in  diabetic  urine.     During  digestion  this  acid  is  also  found  in 

'  See  Chapter  VIII,  p.  211,  and  references  to  the  literature  of  Glycogen  in 
the  above  chapter. 

'  Zeitschr.  f.  physiol.  Chem.,  Bd.  17. 
»  Monatshefte  f.  Chem.,  Bd.   11. 

*  Arch,  des  sciences  biol.  de  St.  Petersbourg,  Tome  1,  p.  199. 

*  Annal.  d.  Chem.  u.  Pharm  ,  Bd.  157. 

*  Pfliiger's  Arch.,  Bd.  8,  S.  171. 


372  MUSGLE. 

the  contents  of  the  stomach  and  intestine,  and  as  alkali  lactate  in 
the  chyle.  The  paralactic  acid  is,  at  all  events,  the  trae  acid  of 
meat  extracts,  and  this  alone  has  been  found  with  certainty  in  dead 
mnscle.  The  lactic  acid  which  is  found  in  the  spleen,  lymphatic 
glands,  thymus,  thyroid  gland,  blood,  bile,  pathological  transuda- 
tions, osteomalacious  bones,  in  perspiration  in  puerperal  fever,  and 
in  the  urine  after  fatiguing  marches,  in  acute  yellow  atrophy  of  the 
liver,  in  poisoning  by  phosphorus,  especially  after  extirpation  of  the 
liver  (in  geese  according  to  Minkowski,'  in  frogs  according  to 
Marcuse''  and  Werther'),  seems  to  be  paralactic  acid. 

The  origin  of  paralactic  acid  in  the  animal  organism  has  been 
sought  by  several  investigators,  who  took  for  basis  the  researches 
of  Gaglio,^  Minkowski,^  and  Araki,'  in  a  decomposition  of 
proteid  in  the  tissues.  Gaglio  claims  a  lactic-acid  formation  by 
passing  blood  through  the  kidneys  and  lungs.  He  also  found 
0.3-0.5  p.  m.  lactic  acid  in  the  blood  of  a  dog  after  proteid  food 
and  only  0.17-0.21  p.  m.  after  fasting  for  48  hours.  According  to 
Minkowski  the  quantity  of  lactic  acid  eliminated  by  the  urine  in 
animals  with  extirpated  livers  is  increased  with  proteid  food,  while 
the  administration  of  carbohydrates  has  no  effect.  Araki  has  also 
shown  that  if  we  produce  a  scarcity  of  oxygen  in  animals  (dogs, 
rabbits,  and  hens)  by  poisoning  with  carbon  monoxide,  by  the 
inhalation  of  air  deficient  in  oxygen,  or  by  any  other  means,  a 
considerable  elimination  of  lactic  acid  (besides  dextrose  and  also 
often  albumin)  takes  place  by  the  urine.  As  a  scarcity  of  oxygen, 
according  to  the  ordinary  statements,  produces  an  increase  of  the 
proteid  katabolism  in  the  body,  the  increased  elimination  of 
lactic  acid  in  these  cases  must  be  due  in  part  to  an  increased  pro- 
teid destruction  and  in  part  to  a  diminished  oxidation. 

Araki  has  not  drawn  such  a  conclusion  from  his  experiments, 
but  he  considers  the  abundant  formation  of  lactic  acid  to  be  due  to 
a  cleavage  of  the  sugar  formed  from  the  glycogen.  He  found  that 
in  all  cases  where  lactic  acid  and  sugar  appeared  in  the  urine 
the  quantity  of   glycogen  in  the   liver   and  muscles  was  always 

1  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  31,  S.  41. 

'■  Pflilger's  Arch.,  Bd.  39. 

3 /Sid.,  Bd.  46. 

•*  Du  Bois-Reymond's  Arch, ,  1886. 

s  Arch.  f.  esp.  Path.  u.  Pharm.,  Bd.  21. 

«  Zeitschr.  f.  physiol.  Chem.,  Bdd.  15,  16,  17,  and  19. 


LACTIC  ACIDS.  373 

diminished.  He  also  calls  attention  to  the  fact  that  dextrolactic 
acid  may  be  formed  from  glycogen,  as  directly  observed  by 
Ekunina,'  and  also  to  the  numerous  observations  on  the  formation 
of  lactic  acid  and  the  consumption  of  glycogen  in  muscular  activity. 
Witliout  denying  the  possibility  of  a  formation  of  lactic  acid  from 
proteid,  he  states  that  with  lack  of  oxygen  we  have  to  deal  with  an 
incomplete  combustion  of  the  lactic  acid  derived  by  a  cleavage  of 
the  sugar.  Hoppe-Seyler''  also  positively  defends  the  view  as  to 
the  formation  of  lactic  acid  from  carbohydrates.  He  is  of  the  view 
that  lactic  acid  is  produced rfrom  the  carbohydrates  by  the  cleavage 
of  the  sugar  only  with  lack  of  oxygen,  while  with  sufficient  oxygen 
the  sugar  is  burnt  into  carbon  dioxide  and  water.  The  formation 
of  lactic  acid  in  the  absence  of  free  oxygen  and  in  the  presence  of 
glycogen  or  dextrose  is,  according  to  Hoppe-Seyler,  very  probably 
a  function  of  all  living  j^rotoplasm.  We  have  good  ground  for  the 
assumption  as  to  the  formation  of  lactic  acid  from  proteid  as  well 
as  from  carbohydrates. 

The  lactic  acids  are  amorphous.  They  have  the  appearance  of 
colorless  or  faintly  yellowish,  acid-reacting  syrups  which  mix  in  all 
proportions  with  water,  alcohol,  or  ether.  The  salts  are  soluble  in 
water,  and  most  of  them  also  in  alcohol.  The  two  acids  are 
differentiated  from  each  other  by  their  different  optical  properties 
— paralactic  acid  being  dextrogyrate,  while  fermentation  lactic 
acid  is  optically  inactive — also  by  their  different  solubilities  and  the 
different  amounts  of  water  of  crystallization  of  the  calcium  and  zinc 
salts.  The  zinc  salt  of  fermentation  lactic  acid  dissolves  in  58-63 
parts  of  water  at  14-15°  C.  and  contains  18.18^  water  of  crystal- 
lization, corresponding  to  the  formula  Zxi{Q,^fi^)^  -f-  3H,0.  The 
zinc  salt  of  paralactic  acid  dissolves  in  17.5  parts  of  water  at  the 
above  temperature  and  contains  ordinarily  12.9^  water,  correspond- 
ing to  the  formula  ZufC^H^O,),  +  3H^0.  The  calcium  salt  of 
fermentation  lactic  acid  dissolves  in  9.5  parts  water  and  contains 
29.22^  (=  5  mol.)  water  of  crystallization,  while  calcium  para- 
lactate  dissolves  in  12.4  parts  water  and  contains  24.83  or  26.21^ 
(=4:  or  4^  mol.)  water  of  crystallization.  Both  calcium  salts 
crystallize,  not  unlike  tyrosin,  in  spheres  or  tufts  of  very  fine  micro- 
scopic needles. 

'  Journal  f.  prakt.  Chem.  (N.  F.),  Bd.  20. 

'  Virchow's  Festschrift,  also  Ber.   d.  deutsch.    chem.    Gesellsch.,   Bd.  25. 
Keferatb.,  S.  685. 


374  MUSCLE. 

Hoppe-Setlee  and  Araki,'  who  have  closely  studied  the 
optical  properties  of  the  lactic  acids  and  lactates,  consider  the 
lithium  salt  as  best  suited  for  the  preparatiou  and  quantitative 
estimation  of  the  lactic  acids.  The  lithium  salt  contains  7.29^  Li. 
They  are  readily  soluble  in  water  and  crystallize  pure  and  anhydrous 
very  easily  from  boiling  alcohol. 

Lactic  acids  may  be  detected  in  organs  and  tissues  in  the  fol- 
lowing manner:  After  complete  extraction  with  water  the  proteid 
is  removed  by  coagulation  at  boiling  temperature  and  the  addition 
of  a  small  quantity  of  sulphuric  acid.  The  liquid  is  then  exactly 
neutralized  while  boiling  with  caustic  baryta,  and  then  evaporated 
to  a  syrup  after  filtration.  The  residue  is  precipitated  with  absolute 
alcohol,  and  the  precipitate  completely  extracted  with  alcohol.  The 
alcohol  is  entirely  distilled  from  the  united  alcoholic  extracts,  and 
the  neutral  residue  is  shaken  with  ether  to  remove  the  fat.  The 
residue  is  dissolved  in  water  and  phosphoric  acid  added,  and 
repeatedly  shaken  with  fresh  quantities  of  ether,  which  dissolves 
the  ] actio  acid.  The  ether  is  now  distilled  from  the  several  ethereal 
extracts,  the  residue  dissolved  in  water,  and  this  solution  carefully 
warmed  on  the  water-bath  to  remove  the  last  traces  of  ether  and 
volatile  acids.  A  solution  of  zinc  lactate  is  prepared  from  this 
filtered  solution  by  boiling  with  zinc  carbonate,  and  this  is  evap- 
orated until  crystallization  commences  and  then  allowed  to  stand 
over  sulphuric  acid.  An  analysis  of  the  salts  is  necessary  in  careful 
work. 

Fat  is  never  absent  in  the  muscles.  Some  fat  is  always  found 
in  the  intermuscular  connective  tissue;  but  the  muscle-fibres  them- 
selves also  contain  fat.  The  quantity  of  fat  in  the  real  muscle 
substance  is  always  small,  usually  amounting  to  about  10  p.  m.  or 
somewhat  more.  A  considerable  quantity  of  fat  in  the  muscle- 
fibres  is  only  found  in  fatty  degeneration.  Lecithin  is  also 
habitually  found  in  the  muscles. 

The  Mineral  Bodies  of  the  Muscles.  We  have  no  complete 
analyses  of  the  mineral  substances  of  the  pure,  blood-free  muscle 
substance.  The  ash  remaining  after  burning  the  muscle,  which 
amounts  to  about  10-15  p.  m.,  calculated  on  the  moist  muscle,  is- 
acid  in  reaction.  The  largest  constituents  are  potassium  and  phos- 
phoric acid.  Next  in  amount  we  have  sodium  and  magnesium,  and 
lastly  calcium,  chlorine,  and  iron  oxide.  Sulphates  only  exist  as 
traces  in  the  muscles,  but  are  formed  by  the  burning  of  the  proteids 
of  the  muscles,  and  therefore  occur  in  abundant  quantities  in  the 
ash.  The  muscles  contain  such  a  large  quantity  of  potassium  and 
'  Zeitschr.  f.  physiol.  Chem..  Bd.  20. 


RIO  OR  MORTIS.  375 

phosphoric  acid  that  potassium  phosphate  seems  to  be  unquestion- 
ably the  predominating  salt.  Chlorine  is  found  in  such  insignifi- 
cant quantities  that  it  is  perhaps  derived  from  a  contamination  with 
blood  or  lymph.  The  quantity  of  magnesium  is  about  double  that 
of  calcium.  These  two  bodies,  as  well  as  iron,  occur  only  in  very 
small  amounts. 

The  gases  of  the  muscles  consist  of  large  quantities  of  carbon 
dioxide,  besides  traces  of  nitrogen. 

Rigger  Mortis  of  the  Muscles.  If  the  influence  of  the  circulating 
oxygenated  blood  is  removed  from  the  m^^scles,  as  after  death  of 
the  animal  or  by  ligature  of  the  aorta  or  the  muscle-arteries 
(Stensok's  test),  rigor  mortis  sooner  or  later  takes  place.  The 
ordinary  rigor  appearing  under  these  circumstances  is  called  the 
spontaneous  or  the  fermentive  rigor,  because  it  seems  to  depend  in 
part  on  the  action  of  an  enzyme.  A  muscle  may  also  become  stiff 
for  other  reasons.  The  muscles  may  become  momentarily  stiff  by 
warming,  in  the  case  of  frogs  to  40°,  in  mammalia  to  48-50°,  and 
in  birds  to  53°  C.  (heat-rigor).  Distilled  water  may  also  produce 
a  rigor  in  the  muscles  (water-rigor).  Acids  even  when  very  weak, 
such  as  carbon  dioxide,  may  quickly  produce  a  rigor  (acid-rigor), 
or  hasten  its  appearance.  A  number  of  chemically  different  sub- 
stances, such  as  chloroform,  ether,  alcohol,  ethereal  oils,  caffein, 
and  many  alkaloids,  produce  a  similar  effect.  The  rigor  which  is 
produced  by  means  of  acids  or  other  agents  which,  like  alcohol, 
coagulate  proteids  must  be  considered  as  produced  by  entirely 
different  processes  from  those  causing  spontaneous  rigor. 

The  time  within  which  the  spontaneous  rigor  occurs  depends 
upon  the  temperature ;  a  low  temperature  retarding  and  a  high  tem- 
perature hastening  its  appearance.  Muscular  activity  also  exercises 
an  appreciable  influence  on  the  rigor  of  the  muscles,  for  a  previous 
active  contraction  accelerates  the  rigor  of  the  muscles ;  the  mechan- 
ical abuse  of  the  muscles  of  various  kinds  operates  in  the  same 
way.  The  appearance  of  spontaneous  rigor  is  under  the  influence 
of  the  central  nervous  system,  and  a  muscle  whose  nerve  has  been 
severed  stiffens  more  slowly  than  one  whose  continuity  with  the 
central  nervous  system  has  not  been  destroyed  (Hermank  and  his 
pupils   Y.   EiSELBERG,'   V.    Gendre,''  and   Bierfreund ').     The 

'  Pfliiger's  Arcli.,  Bd.  24. 
=  Ihid.,  Bd.  35,  S.  45. 
^  Ihid.,  Bd.  43. 


376  MUSCLE. 

nervous  system  seems  also  to  have  a  similar  influence  on  the  post- 
morteiii  acidification  of  the  muscles  (Gross  ').  Hermann  and  his 
pupils  ^  consider  the  rigor  mortis  as  a  final  slowly  proceeding  muscle- 
oontraction  identical  with  the  ordinary  contraction.  Gotschlich  ^ 
has  indeed  made  the  statement  that  rest,  activity,  and  rigor  of  the 
muscles  are  identical  processes  in  principle.  This  cannot  at  present 
be  positively  proven  from  a  chemical  standpoint. 

Wlien  the  muscle  passes  into  ingor  mortis  it  becomes  shorter  and 
thicker,  harder  and  non-transparent,  less  ductile.  The  acid  part 
of  the  amphoteric  reaction  becomes  stronger,  which  is  explained  by 
most  investigators  by  a  formation  of  lactic  acid.  There  is  hardly 
any  doubt  that  this  increase  in  acidity  may  at  least  in  part  be  due 
to  a  transformation  of  a  part  of  the  diphosphate  into  monophosphate 
by  the  lactic  acid.  The  statements  in  regard  to  the  occurrence  also 
.of  free  lactic  acid  or  not  in  the  rigor  mortis  muscle  are  coutradic- 
rtory.''  The  chemical  processes  which  take  place  in  rigor  of  the 
.muscles,  besides  the  formation  of  acid,  are  the  following :  By  the 
coagulation  of  the  plasma  a  myosin-clot  is  produced  which  is  the 
■cause  of  the  hardening  and  of  the  diminished  transparency  of  the 
muscle.  The  appearance  of  this  clot  may  be  hastened  by  the 
simultaneous  occurrence  of  lactic  acid.  Carbon  dioxide  is  also 
formed,  which  does  not  seem  to  be  a  direct  oxidation  product,  but  a 
product  of  the  cleavage  processes.  Hermann  ^  claims  that  carbon 
dioxide  is  produced  in  the  removed  muscle,  even  in  the  absence  of 
-oxygen,  when  it  passes  into  rigor  mortis. 

As  many  investigators  admit  of  an  increased  formation  of  lactic 
acid  on  the  appearance  of  rigor  mortis,  the  question  arises,  from 
what  constituents  of  the  muscle  is  this  acid  derived  ?  The  most 
probable  explanation  is  that  the  lactic  acid  is  produced  from  the 
glycogen,  as  certain  investigators,  such  as  Nasse*^  and  Werther,' 
have  observed  a  decrease  in  the  quantity  of  glycogen  in  rigor  of  the 

1  Centralbl.  f.  Physiol.,  Bd.  2,  S.  91. 
^  See  Bierfreund,  1.  c. 
s  Pfluger's  Arch.,  Bd.  56. 

*  It  is  impossible  to  enter  into  details  of  the  disputed  statements  as  to  the 
reaction  of  the  muscles,  etc.  We  will  only  refer  to  the  works  of  Rohmann, 
Pfliiger's  Arch.,  Bdd.  50  and  55,  and  Hefter,  Arch.  f.  exp.  Path.  u.  Pharm., 
Bd.  31. 

^  Untersachungen  liber  den  StofEwechsel  der  Muskeln,  etc.     Berlin,  1867. 

*  Beitr.  z.  Physiol,  der  Kontraktil.  Substanz,  Pfliiger's  Arch.,  Bd.  3. 
•^  Pfluger's  Arch.,  Bd.  46. 


METABOLISM  IN  THE  MUSCLE.  377 

muscle.  On  the  otlier  side,  Bohm  '  has  obsei'ved  cases  in  which  no 
consumption  of  glycogen  took  place  in  rigor  of  the  muscle,  and  he 
has  also  found  that  the  quantity  of  lactic  acid  produced  is  not  pro- 
portional to  the  quantity  of  glycogen.  It  is  therefore  possible  that 
the  consumjjtion  of  glycogen  and  the  formation  of  lactic  acid  in  the 
muscles  are  two  processes  independent  of  each  other,  and,  as  above 
stated  in  regard  to  the  formation  of  paralactic  acid,  the  lactic  acid 
of  the  muscle  may  be  considered  as  a  decomposition  product  of 
proteid.  The  origin  of  the  carbon  dioxide  is  also  not  to  be  sought 
for  in  the  decomposition  of  the  glycogen  or  dextrose.  Pflugbr 
and  Stintzing  "  have  found  that  in  the  muscle  a  substance  occurs 
which  evolves  large  quantities  of  carbon  dioxide  on  boiling  with 
water,  and  it  is  probably  this  substance  which  is  decomposed  with 
the  formation  of  carbon  dioxide  in  tetanus  as  well  as  in  rigor. 
TissoT "  has  observed  a  true  respiration  in  removed  muscle,  which 
is  independent  of  the  putrefactive  processes,  and  by  which  oxygen 
is  absorbed  and  carbon  dioxide  eliminated,  this  being  contrary  to 
Heemann's  assertion.  The  carbon  dioxide  eliminated  originates 
from  two  sources.  A  part  is  preformed  in  the  muscle  and  is  only 
physically  evolved  carbon  dioxide,  and  another  part  is  formed  in  the 
removed  muscle. 

After  the  muscles  have  been  rigid  for  some  time  they  relax  again 
and  the  muscles  become  softer.  This  is  in  part  produced  by  the 
strong  acid  dissolving  the  myosin  clot  and  in  part,  and  in  all  prob- 
ability mainly,  upon  the  commencement  of  jiut refaction. 

Metabolism  in  the  Inactive  and  Active  Muscles.  It  is  admitted 
by  a  number  of  prominent  investigators,  Pfluger  and  Colas anti,* 
ZuNTZ  and  Rohrig,*  and  others,  that  the  exchange  of  material  in 
the  muscles  is  regulated  by  the  nervous  system.  When  at  rest, 
when  there  is  no  mechanical  exertion,  we  have  a  condition  which 
ZuxTZ  and  Rohrig  have  designated  ^^  chemical  totms.''''  This 
tonus  seems  to  be  a  reflex  tonus,  for  it  may  be  reduced  by  discon- 
tinuing the  connection  between  the  muscles  and  the  central  organ 
of  the  nervous  system  by  cutting  through  the  spinal  cord  or  the 

»  Pflllger's  Arch.,  Bdd.  33  and  46. 
^  Ibid.,  Bd.  18. 

^  Arch,  de  Physiol.,  Ser.  5,  Tome  7. 

•*  See  the  works  of  Pfluger  and  his  pupils  in  Pflllger's  Arch.,  Bdd.   4,  13, 
14,  16,  18. 

^Ibid.,  Bd.  4,  S.  57  ;  also  Zuntz.,  ibid.,  Bd.  18,  S.  523. 


378  MUSCLE. 

muscle-nerves,  or  by  paralyzing  the  same  by  means  of  cnrara  poison. 
It  may  also  be  reduced  or  checked  by  adjusting  the  temperature 
between  the  skin  and  the  surrounding  medium;  or  it  may  be 
increased  by  the  reverse,  by  irritating  the  nerves  of  the  skin  by 
cooling.  The  possibility  of  reducing  the  chemical  tonus  of  the 
muscles  by  any  of  the  above-mentioned  means,  but  especially  by  the 
action  of  curara,  offers  an  important  means  of  deciding  the  extent 
and  kind  of  chemical  processes  going  on  in  the  muscles  when  at 
rest.  In  comparative  chemical  investigation  of  the  processes  in  the 
active  and  the  inactive  muscles  several  methods  of  procedure 
have  been  adopted.  The  removed  homologous,  active  and  inactive 
muscles  have  been  compared,  also  the  arterial  and  venous  muscle- 
blood  in  rest  and  activity,  and  lastly  the  total  exchange  of  material, 
the  receipts  and  expenditures  of  the  organism,  have  been  investi- 
gated under  these  two  conditions. 

By  investigations  according  to  these  several  methods  it  has 
been  found  that  the  active  muscle  takes  up  oxygen  from  the  blood 
and  returns  to  it  carbon  dioxide,  and  also  that  the  quantity  of 
oxygen  taken  up  is  greater  than  the  oxygen  contained  in  the  carbon 
dioxide  eliminated  at  the  same  time.  The  muscle,  therefore,  holds 
in  some  form  of  combination  a  part  of  the  oxygen  taken  up  while  at 
rest.  During  activity  the  exchange  of  material  in  the  muscle,  and 
therewith  the  exchange  of  gas,  is  increased.  The  animal  organism 
takes  up  considerably  more  oxygen  in  activity  than  when  at  rest, 
and  eliminates  also  considerably  more  carbon  dioxide.  The  quan- 
tity of  oxygen  which  leaves  the  body  as  carbon  dioxide  during 
activity  is  considerably  larger  than  the  quantity  of  oxygen  taken  up 
at  the  same  time ;  and  the  venous  muscle-blood  is  poorer  in  oxygen 
and  richer  in  carbon  dioxide  during  activity  than  during  rest. 
The  exchange  of  gases  in  the  muscles  during  activity  is  the  reverse 
of  that  at  rest,  for  the  active  muscle  gives  up  a  quantity  of  carbon 
dioxide  which  does  not  correspond  to  the  quantity  of  oxygen  taken 
up,  but  is  considerably  greater.  It  follows  from  this  that  in 
muscular  activity  not  only  does  oxidation  take  place,  but  also  split- 
ting processes  occur.  This  follows  also  from  the  fact  that  removed 
blood-free  muscles  when  placed  in  an  atmosphere  devoid  of  oxygen 
can  labor  for  some  time  and  also  yield  carbon  dioxide  (Hermann  '). 

During  muscular  inactivity,  in  the  ordinary  sense,  a  consump- 
tion of  glycogen  takes  place.    This  is  inferred  from  the  observations 

'  L.  c. 


CONSUMPTION  OF  GLYCOGEN  IN  THE  MUSCLE.        379 

of  several  investigators  that  the  quantity  of  glycogen  is  increased 
and  its  corresponding  consumption  reduced  in  those  muscles  whose 
chemical  tonus  is  reduced  either  by  cutting  through  the  nerve  or 
for  other  reasons  (Bernard,'  CKANDELO]sr,'  Wat/  and  others). 
In  activity  this  consumption  of  glycogen  is  increased,  and  it  has 
been  positively  proved  by  the  researches  of   several  investigators 
(Nasse,*    Weiss,'    Kulz,'    Marcuse,'    Manche,'   Morat    and 
DuFOUR°)    that   the   quantity   of    glycogen    in    the    muscles   in 
activity  decreases  quickly  and  freely.     By  investigating  with  the 
muscles  in   situ,  especially  on  the   levator  lahii  superioris   of  a 
horse,  Chauveau  and  Kaufmanst  '"  have  not  only  confirmed  the 
above   facts   in  regard   to   the   exchange  of   gas   during  rest  and 
activity,  but  they  also  found  that  the  muscles  remove  sugar  from 
the   blood,   and    indeed    considerably    more   during   activity  than 
when   at   rest.     They   found    (calculating   the   amount  found    in 
1  gramme  of  muscle  per  minute  to  1  kilo  per  hour)  that  1  kilo 
of  muscle  removes  2.186  grms.   sugar  from   the    blood   per  hour 
during  rest,  while  it  removes  8.416  grms.   per  hour  in  activity. 
Strong  objections  to  the  conclusions   drawn   from   these   experi- 
ments have  been  made  by  Seegen'';    although  these  experiments 
may   not   be    quite  conclusive,  still  it   cannot  be  denied  that  an 
increased  consumption  of  sugar  takes  place  during  activity.      Other 
investigators,  such  as  Quinquaud,"  Morat  and  Dufour,   have 
observed  a  consumption  of  the  sugar  derived  from  the  blood  during 
work,  and  finally  in  this  connection  we  must  recall  that  Seegeis"  '* 
and  still  earlier  Chauveau  have  come  to  a  similar  conclusion  by 
special  investigations.     According  to  Seegen  the  blood-sugar  is  on 
the  whole  the  source  of  heat  and  work.     Seegejst  '*  has  determined 
'  Compt.  rend.,  Tome  48,  p.  673. 
»  Pfluger's  Arch. ,  Bd.  13. 
3  Arch.  f.  exp.  Patli.  u.  Pharm.,  Bd.  34. 

*  Pfluger's  Arch.,  Bd.  2. 

*  Wien.  Sitzungsber. ,  Bd.  64,  Abtli.  1. 

*  See  Killz  in  Ludwig's  Festschrift.     Marburg,  1891. 
'Pfluger's  Arch.,  Bd.  39. 

«  Zeitschr.  f.  Biologie,  Bd.  25. 
9  Arch,  de  Physiol.  (5)  Bd.  4. 
JO  Compt.  rend.,  Tome  103.  104,  and  105. 
"  Centralbl.  f.  Physiol.,  Bd.  8,  S.  417. 
"  Maly's  Jahresber.,  Bd.  16,  S.  321. 

"  Die  Zuckerbildung  im  Thierkorper  (Berlin,  1890),  and  Pflliger's  Arch.,. 
Bd.  50. 

'^  Centralbl.  f.  Physiol.,  Bd.  8,  and Du  Bois-Reymond's  Arch.,  1895. 


380  MUSCLE. 

the  quantity  of  sugar  in  the  arterial  and  venous  blood  of  the  muscle 
during  rest  and  when  directly  or  indirectly  irritated,  but  obtained 
no  constant  results.  He  found,  on  the  contrary,  generally  a  very 
considerable  consumption  of  the  glycogen  in  the  active  muscles. 
Seegek  calculates  that  in  his  experiments,  with  the  assumption 
that  the  glycogen  was  completely  oxidized,  the  glycogen  in  great- 
est part  served  as  heat-former  and  only  to  a  small  extent,  in  most 
cases  5-10^  of  its  store  of  energy,  as  mechanical  work.  The  entire 
quantity  of  glycogen  in  the  animal  body  is,  according  to  Seegekt, 
only  sufficient  to  supply  a  small  fraction  of  the  mechanical  work  of 
the  body,  and  the  most  important  source  of  mechanical  work  and 
of  heat  lies,  according  to  him,  in  the  blood-sugar. 

The  amphoteric  reaction  of  the  inactive  muscles  is  changed 
during  activity  to  an  acid  reaction  (DuBois-Eetmont)  and  others), 
and  the  acid  reaction  increases  to  a  certain  point  with  the  work. 
The  quickly  contracting  pale  muscles  produce,  according  to 
CrLEiss,'  more  acid  during  activity  than  the  more  slowly  contract- 
ing red  muscles.  The  acid  reaction  appearing  during  activity  was 
formerly  considered  due  to  the  formation  of  lactic  acid,  a  view 
which  has  been  contradicted  by  Astaschewsky,''  Ppluger  and 
Waeren",'  who  found  less  lactic  acid  in  the  tetanized  muscle  than 
when  at  rest.  Mon'ARI  ^  also  found  a  decrease  in  the  quantity  of 
lactic  acid  during  activity,  and  according  to  Hefter  ^  the  quantity 
of  lactic  acid  in  the  muscle  is  diminished  in  tetanus  produced  by 
poison.  Contrary  to  these  investigations  M arouse  °  and  Werther  ' 
have  been  able  to  prove  the  formation  of  lactic  acid  during  activity; 
still  the  statements  are  very  contradictory.  Other  observations 
speak  for  a  formation  of  lactic  acid  during  activity.  Thus 
Spiro  *  found  an  increase  in  the  quantity  of  lactic  acid  in  the 
blood  during  work.  Colasaistti  and  Moscatelli'  found  small 
quantities  of  lactic  acid  in  human  urine  after  strenuous  marches, 
and  Werther  observed  abundance  of  lactic  acid  in  the  urine  of 

'  PflUger's  Arcli.,  Bd.  41. 

^  Zeitschr.  f.  pliysiol.  Cliem.,  Bd.  4. 

»  Pfliiger's  Arch.,  Bd.  34. 

*  Maly's  Jahresber. ,  Bd.  19,  S.  303. 

^  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  31. 

«  L.  c. 

'  Pfliiger's  Arch.,  Bd.  46. 

*  Zeitschr.  f.  pliysiol.  Chem.,  Bd.  1. 
9  Maly's  Jahresber.,  Bd.  17,  S.  212. 


REACTION  OF  THE  MUSCLE.  '6>il 

frogs  after  tetanization.  According  to  Hoppe-Seyler,'  on  tlie 
contrary,  in  agreement  with  his  view  in  regard  to  the  formation  of 
lactic  acid,  a  formation  of  lactic  acid  does  not  take  place  regularly 
during  work,  but  only  when  insufficient  oxygen  is  supplied.  Zille- 
SEsr "  has  also  found  that  on  artificially  cutting  off  the  oxygen  from 
the  muscles  during  life  more  lactic  acid  was  formed  than  under 
normal  conditions. 

It  is  evident  that  the  experiments  with  the  muscles  in  situ,  in 
other  words  with  muscles  through  which  blood  is  passing,  cannot 
yield  any  conclusion  to  the  above  question,  as  the  lactic  acid 
formed  during  work  may  perhaps  be  removed  by  the  blood.  The 
following  objections  can  be  made  against  those  experiments  in 
which  lactic  acid  has  been  found  after  moderate  work  in  the  blood 
or  the  urine,  as  also  especially  against  the  experiments  with  re- 
moved active  muscles,  namely,  that  in  these  cases  the  supply  of 
oxygen  to  the  muscles  was  not  sufficient,  and  that  the  lactic  acid 
formed  thereby  is  not,  corresponding  to  the  views  of  Hoppe-Seyler, 
a  perfectly  normal  process.  The  question  as  to  the  formation  of 
lactic  acid  in  the  active  muscle  under  perfectly  jihysiological  con- 
ditions is  still  an  open  one. 

According  to  Weyl  and  Zeitler,'  the  active  muscle  contains 
more  phosphoric  acid  (in  part  formed  by  the  decomposition  of 
lecithin)  than  the  inactive  muscle.  As  in  the  dead  muscle,  so  in 
the  active  muscle,  the  somewhat  stronger  acid  reaction  is  in  part 
due  to  a  greater  quantity  of  monophosphate. 

The  amount  of  proteids  in  the  removed  muscles  is,  according 
to  the  older  investigators,  decreased  by  work.  The  correctness  of 
this  statement  is,  however,  disputed  by  other  investigators.  Also 
the  older  statements  in  regard  to  the  nitrogenous  extractive  bodies 
of  the  muscle  in  rest  and  in  activity  are  uncertain.  According  to 
the  recent  researches  of  Moxari,*  the  total  quantity  of  creatin  and 
creatinin  is  increased  by  work;  and  indeed  the  amount  of  creatinin 
IS  especially  augmented  by  an  excess  of  muscular  activity.  The 
creatinin  is  formed  essentially  from  the  creatin.  In  excessive 
activity  Moxari  also  found  xantho-creatinin  in  the  muscle,  and 
the  quantity  was  one  tenth  of  that  of  the  creatinin.     The  quantity 

1  L.  c.  and  Zeitschr.  f.  pliysiol  Chem.,  Bd.  19,  S.  476. 
»  Zeitschr.  f.  physiol.  Chem.,  Bd.  15. 
'  Zeitschr.  f.  physiol.  Chem.,  Bd    6,  S.  557. 
^Maly's  Jahresber.,  Bd.  19,  S.  296. 


382  MUSCLE. 

of  xanthin  bodies  is,  according  to  Monari,  decreased  under  the 
influence  of  work.  It  seems  to  have  been  positively  shown  that  the 
active  muscle  contains  a  smaller  quantity  of  bodies  soluble  in  water 
and  a  larger  quantity  of  bodies  soluble  in  alcohol  than  the  resting 
muscle  (Helmholtz).' 

An  attempt  has  been  made  to  solve  the  question  relative  to  the 
behavior  of  the  nitrogenized  constituents  of  the  muscle  at  rest  and 
during  activity  by  determining  the  total  quantity  of  nitrogen 
eliminated  under  these  different  conditions  of  the  body.  While 
formerly  it  was  held  with  Liebig  that  the  elimination  of  nitrogen 
by  the  urine  was  increased  by  muscular  work,  the  researches  of 
several  experimenters,  especially  those  of  Yoit'  on  dogs  and 
Pettenkofee  and  Voit^  on  men,  have  led  to  quite  different 
results.  They  have  shown,  as  has  also  lately  been  confirmed  by 
other  investigators,  especially  Hieschfeld,^  that  during  work  no 
increase  or  only  a  very  insignificant  increase  in  the  elimination  of 
nitrogen  takes  place.  We  should  not  omit  to  mention  the  fact 
that  a  series  of  experiments  has  been  made  showing  a  significant 
increase  in  the  metabolism  of  proteids  during  or  after  work. 
We  have  as  example  the  observations  of  Flint  ^  and  Pavt  '  on  a 
pedestrian,  v.  Wolff,  v.  Funke,  Keeuzhage  and  Kellnee  '  on 
a  horse,  and  lately  those  of  Argutinsky  '  and  Krummachee  '  on 
themselves,  which  show  an  undoubted  increase  in  the  elimination 
of  nitrogen  during  or  after  work. 

The  elimination  of  nitrogen  is  mainly  dependent  upon  causes 
which  will  be  spoken  of  later  (Chapter  XVIII),  such  as  the  quantity 
and  composition  of  the  food,  the  condition  of  the  adipose  tissue, 
the  action  of  work  on  the  respiratory  mechanism,  etc.,  etc.,  all  of 
which  can  hardly  have  received  sufficient  consideration  in  the  last- 

1  Arch.  f.  Anat.  u.  Physiol.,  1845. 

*  Untersucbungen  tlber  den  Einfluss  des  Kochsalzes,  des  KafEees  und  der 
Muskelbewegungen  auf  den  Stoffwechsel  (Miinchen,  1860),  and  Zeitschr.  f. 
Biologie,  Bd.  2. 

3  Zeitschr.  f.  Biologie,  Bd.  2. 

4  Virchow's  Arch.,  Bd.  121. 

^  Journal  of  Anat.  and  Physiol.,  Vols.  11  and  12. 

«  The  Lancet,  1876  and  1877. 

'  Cited  by  Voit  in  Hermann's  Handbuch,  Bd.  6,  S.  197. 

8  Pflilger's  Arch..  Bd.  46. 

9i6id.,Bd.  47. 


ELIMINATION  OF  NITROGEN.  383 

mentioned  experiments. '  The  strong  proof  which  the  very  careful 
experiments  of  Voit,  of  Pettenkofer  and  Voit,  and  of  Hirsch- 
FELD  furnish  in  sui3port  of  this  theory  is  hardly  affected  by  these 
investigations,  though  we  must  admit  that  this  question  is  still  some- 
what unsettled.  Even  if  we  consider  the  question  that  muscular 
work  does  not  cause  any  increase  in  the  elimination  of  nitrogen  as 
quite  positively  proved,  still  we  do  not  exclude  the  possibility  of  an 
increased  metabolism  of  proteids  in  the  muscle.  It  is  possible  on 
account  of  the  functional  exchange  action  of  the  organs,  of  which 
Eanke  '  has  made  a  special  study,  that  an  increased  metabolism  of 
proteid  in  the  muscles  may  be  compensated  by  a  simultaneous 
decreased  metabolism  of  proteid  in  other  organs.  But  however  this 
may  be,  the  modern  view  is,  notwithstanding,  that  the  metabolism 
of  proteid  in  the  muscle  is  not  increased  by  activity. 

The  quantity  of  metabolic  products  containing  sulphur  may 
also  be  a  measure  of  the  extent  of  the  metabolism  of  proteids, 
and  this  quantity  may  be  determined  by  estimating  the  suphur  in 
the  urine.  An  increase  in  the  elimination  of  sulphur  after  work 
has  been  observed  for  a  long  time  by  Engelmann,'  and  also  by 
Flint  and  Pavy.  As  sulphuric  acid  and  also  non-oxidized  sul- 
phur are  eliminated  by  the  urine,  it  is  necessary  to  determine  the 
total  sulphur  eliminated  during  work  and  after  work.  Beck  and 
Benedikt*  have  made  investigations  of  this  kind,  and  they  find 
that  the  elimination  of  sulphur  is  increased  by  work  and  diminished 
after  work,  which  speaks  for  an  increased  proteid  metabolism 
during  work.  I.  Mujstk  ^  by  observations  on  resting  and  working 
persons  has  given  further  proof  that  the  elimination  of  nitrogen 
and  sulphur  (also  phosphoric  acid  and  potash)  runs  parallel  with 
the  metabolism  of  proteid.  The  increased  elimination  of  sulphur 
was  not  in  the  neutral  sulphur,  but  nearly  entirely  in  the  oxidized 
sulphur. 

The  investigations  on  the  amount  of  fat  in  removed  muscles 
during  activity  and  at  rest  have  not  led  to  any  definite  results. 
The  metabolic  experiments  of  Voit  on  a  starving  dog,  and  those  of 

'  See  Voit  in  Hermann's  Handbuch,  Bd.  6,  Kap.  3,  Abschn.,  9;  I.  Munk, 
Du  Bois-Reymond's  Arch.,  1890;  and  Hirscbfeld,  1.  c. 

'^  Die  Blutvertheilung  und  der  Thatigkeitawechsel  der  Organe.  Leipzig, 
1871. 

'  Du  Bois-Reymond's  Arch. ,  1871. 

*  Pfliiger's  Arch.,  Bd,  54. 

*  Verhandl.  d.  physiol.  Qesellsch.  zu  Berlin,  1894-95. 


384  MUSCLE. 

Pettenkopee  and  Voit  on  a  man,  offer  strong  proofs  to  show  that 

an  increased  decomposition  of  the  fat  takes  place  during  activity. 

If  the  results  of  the  investigations  thus  far  made  of  the  chemical 

processes  going  on  in  the  active  and  inactive  muscle  were  collected 

together,  we  would  find  the  following  characteristics  for  the  active 

muscle.     The  active  muscle  takes  up  more  oxygen  and  gives  off 

more  carbon  dioxide  than  the  inactive  muscle ;  still  the  elimination 

of  carbon  dioxide  is  increased  considerably  more  than  the  absorption 

CO, 
of  oxygen.     The  respiratory  quotient,  -pp'  is  found  to  be  regularly 

raised  during  work  ;  still  this  rise,  which  will  be  explained  in  detail 
in  a  following  chapter  on  metabolism,  can  hardily  be  conditioned  on 
the  kind  of  processes  going  on  in  the  muscle  during  activity  with  a 
sufficient  supply  of  oxygen.  In  work  a  consumption  of  carbohy- 
drates, glycogen,  and  sugar  takes  place.  A  consumption  of  sugar 
seems  only  to  have  been  shown  in  muscle  with  blood  circulation, 
while  a  consumption  of  glycogen  also  has  been  observed  in  removed 
muscle.  The  acid  reaction  of  the  muscle  becomes  greater  with  work. 
In  regard  to  the  extent  of  a  re-formation  of  lactic  acid  opinion  is 
divided.  Respecting  the  behavior  of  fats  in  removed  muscles 
nothing  is  known  with  certainty,  though  an  increase  in  the  con- 
sumption of  fat  in  the  organism  has  been  observed  in  certain  cases 
during  activity.  An  increase  in  the  nitrogenous  extractive  bodies 
of  the  creatin  group  seems  also  to  occur.  In  regard  to  the  proteid 
bodies  the  views  are  contradictory  ;  but  an  increased  elimination 
of  nitrogen  as  a  direct  consequence  of  muscular  exertion  has  thus 
far  not  been  positively  proved. 

In  close  connection  with  the  above-mentioned  facts  we  have  the 
question  as  to  the  origin  of  muscular  activity  so  far  as  it  has  its 
origin  in  chemical  processes.  In  the  past  the  generally  accepted 
opinion  was  that  of  Liebig,  that  the  source  of  muscular  action  con- 
sisted of  a  metabolism  of  the  proteid  bodies;  to-day  another  gener- 
ally accepted  view  prevails.  Tick  and  Wislicenus  '  climbed  the 
Faulhorn  and  calculated  the  amount  of  mechanical  force  expended 
in  the  attempt.  With  this  they  compared  the  mechanical  equiva- 
lent transformed  in  the  same  time  from  the  proteids,  calculated 
from  the  nitrogen  eliminated  with  the  urine,  and  found  that  the 
work  really  performed  was  not  by  any  means  compensated  by  the 

'■  Vierteljalarschr.  d.  Ziiricli.  naturf.  Gesellscli.,  Bd.  10.  Cited  from  Cen- 
tralbl.  f.  d.  med.  Wiss.,  1866,   S.  309. 


SOURCE  OF  MUSCULAR  FORCE.  385 

consumption  of  proteid.  It  was  therefore  proved  by  this  that  pro- 
teids  alone  cannot  be  the  source  of  muscular  activity,  and  that  this 
depends  in  great  measure  on  the  metabolism  of  non-nitrogenous 
substances.  Many  other  observations  have  led  to  the  same  result, 
especially  the  experiments  of  VoiT,  of  Pettenkofer  and  Voit,  and 
of  other  investigators,  whose  experiments  show  that  while  the  elim- 
ination of  nitrogen  remains  unchanged,  the  elimination  of  carbon 
dioxide  during  work  is  very  considerably  increased.  It  is  alsO' 
generally  considered  as  positively  proved  that  muscular  work  is 
jjroduced,  at  least  the  greatest  part,  by  the  metabolism  of  non- 
nitrogenous  substances.  Nevertheless  we  are  not  warranted  in 
the  statement  that  muscular  activity  is  produced  entirely  at  the 
cost  of  the  non-nitrogenous  substances,  and  that  the  proteid  bodies 
are  without  importance  as  a  source  of  force. 

The  recent  investigations  of  Pfluger  '  are  of  great  interest  in 
this  connection.  He  fed  a  bulldog  for  more  than  7  months  with 
meat  which  alone  did  not  contain  sufficient  fat  and  carbohydrates 
for  the  production  of  heart  activity,  and  then  let  him  work  very 
hard  for  periods  of  14,  35,  and  41  days.  The  positive  results  ob- 
tained by  these  series  of  experiments  was  that  "complete  muscular 
activity  may  be  effected  to  the  greatest  extent  in  the  absence  of  fat 
and  carbohydrates,"  and  the  ability  of  proteids  to  serve  as  a  source 
of  muscular  energy  cannot  be  denied. 

Among  the  non-nitrogenous  bodies  we  must  accord  to  carbohy- 
drates, glycogen,  and  sugar  the  first  place  as  sources  of  force. 
That  the  fats  are  also  to  be  considered  as  a  source  for  force  is  very 
probable,  and  the  researches  of  Voit  ^  on  starving  and  working  dogs 
give  support  to  this  theory.  The  view,  as  accepted  by  several  in- 
vestigators, that  all  three  chief  groups  of  organic  food  or  muscle 
constituents  may  serve  as  source  of  force  seems  to  be  true.  A  few 
investigators  are  of  the  opinion,  as  formulated  by  Bunge,'  that  the 
muscles  first  consvime  the  supply  of  non-nitrogenous  nutritive  bodies, 
and  that  the  proteids  are  only  secondarily  attacked.  Pfluger  is, 
on  the  contrary,  of  the  opposite  opinion.  According  to  him  no 
muscular  work  takes  place  without  a  decomposition  of  proteid,  and 
the  living  cell  substance  prefers  always  the  proteid  and  rejects  the 
fat  and  sugar,  contenting  itself  with  these  only  when  proteids  are 
absent. 

'  Pflllger's  Arch.,  Bd.  50. 

"^  Ueber  den  Einflnss  des  Kocbsalzes,  etc.,  1.  c. 

'  Lelirbuch  d.  pbysiol.  u.  pathol.  Chem.,  1.  Auli.,  S.  345. 


386  MUSCLE. 

ZuiSTTz/  in  collaboration  with  Feektzel  and  Loeb,  has  made 
^experiments  in  dogs  from  which  he  concludes,  that  at  least  in  these 
experiments  (part  in  starvation  and  part  with  such  an  abundant  food 
that  a  deposition  of  nitrogen  took  place  even  after  hard  work)  the 
animals  preferred  the  non-nitrogenous  bodies  which  were  offered  as 
food  to  defray  the  work  done.  Zuntz  has  also  shown  that  the 
foods  may  supply  work  approximately  in  proportion  as  they  con- 
•^ume  oxygen  and  according  to  their  heat  of  combustion. 

Quantitative  Composition  of  the  Muscle.  A  large  number  of 
analyses  have  been  made  of  the  flesh  of  various  animals  for  purely 
practical  purposes,  in  order  to  determine  the  nutritive  value  of 
different  varieties  of  meat;  but  we  have  no  exact  scientific  analyses 
with  sufficient  regard  to  the  quantity  of  different  albuminous  bodies 
and  the  remaining  muscle-constituents,  or  these  analyses  are  in- 
(Complete  or  of  little  value. 

To  give  the  reader  some  idea  of  the  variable  composition  of 
muscle-substance  we  give  the  following  summary,  chiefly  obtained 
from  K.  B.  Hofmann's'  book.     The  figures  are  parts  per  1000. 

Muscles  of 
Muscles  of  Muscles  of         Cold-blooded 

Mammalia.  Biids.  Animals. 

Solids 217-255  227-282  200 

Water 745-783  717-773  800 

Organic  bodies 208-245  217-263  180-190 

Inorganic  bodies 9-10  10-19  10-20 

Myosin 35-106  29.8-111  29.7-87 

Stroma  substance  (Danilewskt) 78-161  88.0-184  70.0-121 

Alkali  albuminate .  .  29  30  —                      — 

Creatin 2  3.4                     2.3 

Xanthin  bases 0.4-0.7  0.7-0  3                  — 

Inosi  nic  acid  (barium  salt) 0. 1  0. 1-0.3                  — 

Protic  acid —  —                      7.0 

Taurin 0.7  (horse)  —                      1.1 

Inosit 0.03  —                      — 

Glycogen 4-5  —                      3-5 

Lactic  acid 0.4-0.7  —                      — 

Pliospboric  acid 3.4-4  8 

Potash 3  0-4.0 

Soda 0.4 

Lime 0  2 

Mag-nesia 0  4 

Sodium  chloride 0.04-0  1 

Iron  oxide 0.03-0.1 

In  this  table,  which  has  little  value  because  of  the  variation 
in  the  composition  of  tlie  muscles,  we  have  no  results  as  to  the 

'  Du  Bois-Reymond's  Arch.,  1894. 

«  Lehrbuch  d.  Zoochem.  Wien,  1876,  S.  104. 


COMPOSITION  OF  THE  MUSCLE.  387 

estimates  of  fat.  Owing  to  the  variable  quantity  of  fat  iu  meat 
it  is  hardly  possible  to  quote  a  positive  average  for  this  body.  After 
most  careful  efforts  to  remove  the  fat  from  the  muscles  without 
chemical  means,  it  has  been  found  that  a  variable  amount  of  inter- 
muscular fat,  which  does  not  really  belong  to  the  muscular  tissue, 
always  remains.  The  smallest  quantity  of  fat  in  the  muscles  from 
lean  oxen  is,  according  to  Gkouven,  6.1  p.  m.,  and  according  to 
Peteksek  7.6  p.  m.  This  last  observer  also  found  regularly  a 
smaller  amount  of  fat,  7.6-8.6  p.  m.,  in  the  fore  quarter  of  oxen, 
and  a  greater  amount,  30.1-34.6  p.  m.,  in  the  hind  quarter  of  the 
animal.  A  low  amount  of  fat  has  also  been  found  in  the  muscles 
of  wild  animals.  B.  Konig  and  Farwick  found  10.7  p.  m.  fat  in 
the  muscles  of  the  extremities  of  the  hare,  and  14.3  p.  m.  in  the 
muscles  of  the  partridge.  The  muscles  of  pigs  and  fattened  ani- 
mals are,  when  all  the  adherent  fat  is  removed,  very  rich  in  fat, 
amounting  to  40-90  p.  m.  The  muscles  of  certain  fishes  also  con- 
tain a  large  amount  of  fat.  According  to  ALMEiiT,  the  flesh  of  the 
salmon,  mackerel,  and  eel  contains  respectively  100,  164,  and  339 
p.  m.  fat.' 

The  quantity  of  water  in  the  muscle  is  liable  to  considerable 
variation.  The  amount  of  fat  has  a  special  influence  on  the  quan- 
tity of  water,  and  we  find,  as  a  rule,  that  the  flesh  which  is  deficient 
in  water  is  correspondingly  rich  in  fat.  The  quantity  of  water  does 
not  depend  alone  upon  the  amount  of  fat,  but  upon  many  other 
circumstances,  among  which  we  must  mention  the  age  of  the  ani- 
mal. In  young  animals  the  organs  in  general,  and  therefore  also 
the  muscles,  are  poorer  in  solids  and  richer  in  water.  In  man  the 
amount  of  water  decreases  until  mature  age,  but  increases  again 
towards  old  age.  Work  and  rest  also  influence  the  amount  of  water, 
for  the  active  muscle  contains  more  water  than  tlie  inactive.  The 
uninterruptedly  active  heart  should  therefore  be  the  muscle  richest 
in  water.  That  the  amount  of  water  may  vary  independently  of  the 
amount  of  fat  is  strikingly  shown  by  comparing  the  muscles  of  dif- 
ferent species  of  animals.  In  cold-blooded  animals  the  muscles 
generally  have  a  greater  amount  of  water,  iu  birds  a  lower.  The 
comparison  of  the  flesh  of  cattle  and  fish  shows  very  strikingly  the 
different  amounts  of  water  (independent  of  the  amount  of  fat)  in 

'  In  regard  to  tlie  literature  and  complete  statements  on  the  composition  of 
flesh  of  various  animals,  see  Konig,  Chemie  der  menschlichen  Nahrungs-  and 
Genussmittel,  3.  Aufl. 


388  MUSCLE. 

the  flesh  of  different  animals.  According  to  the  analysis  of  Almen/ 
the  muscles  of  lean  oxen  contain  15  p.  m.  fat  and  767  p.  m.  water; 
the  flesh  of  the  pike  contains  only  1.5  fat  and  839  p.  m.  water. 
For  certain  purposes,  as,  for  example,  in  experiments  on  meta- 
bolism, it  is  important  to  know  the  elementary  composition  of 
flesh.  In  regard  to  the  quantity  of  nitrogen  we  generally  accept 
Voit's  "^  figure,  namely,  3.4^,  as  an  average  for  fresh  lean  meat. 
According  to  ISTowak  '  and  Huppert  '  this  quantity  may  vary 
about  0.6^,  and  in  more  exact  investigations  it  is  therefore  neces- 
sary to  specially  determine  the  nitrogen.  According  to  Salkow- 
SKi,"  of  the  total  nitrogen  of  beef  77.4^  was  insoluble  proteids, 
10.08^  soluble  proteids,  and  12.52^  other  soluble  bodies.  Complete 
elementary  analyses  of  flesh  have  recently  been  made  with  great  care 
by  ARGUTiisrsKY.^  The  average  for  ox-flesh  dried  in  vacuo  and  free 
from  fat  and  with  the  glycogen  deducted  was  as  follows:  C  49.6; 
H  6.9;  N  15.3;  0  -f  S  23.0;  and  ash  5.2^.  The  relationship  of  the 
carbon  to  nitrogen,  which  Argutinsky  calls  the  ''flesh  quoti- 
ent," is  on  an  average  3.24: 1. 

Non-striated  Muscles. 

The  smooth  muscles  have  a  neutral  or  alkaline  reaction  (Du- 
Bois-Eeymond)'  when  at  rest.  During  activity  they  are  acid, 
which  is  inferred  from  the  observations  of  Bernstein,'  who  found 
that  the  nearly  continually  contracting  sphincter  muscle  of  the 
Anodonta  is  acid  during  life.  The  smooth  muscles  may  also,  ac- 
cording to  Heidenhain  *  and  Kuhne,'"  pass  into  rigor  mortis  and 
thereby  become  acid.  Because  of  this  behavior  it  is  believed  that 
among  the  proteid  bodies  of  the  smooth  muscles  there  is  also  a 
myosin-forming  substance.  A  spontaneously  coagulating  plasma 
has  not  thus  far  been  obtained,  but  it  may  be  considered  as  the 

-  Nova   Act.   reg.   Soc.  Scient.   Upsal.,  Vol.  extr.  ord.,  1877;  also     Maly's 
Jahresber.,  Bd.  7,  S.  307. 

«  Zeitscbr.  f.  Biologie,  Bd.  1. 

3  Wien.  Sitzungsber.,  Bd.  64,  Abth.  2. 

*  Zeitscbr.  f.  Biologie,  Bd.  7. 

5  Centralbl.  f.  d.  med.  Wissensch.,  1894. 

*  Pflilger's  Arcb.,  Bd.  55. 

'  Cited  by  Nasse  in  Hermann's  Handb.,  Bd.  1,  S.  339. 
» Ibid. 

9  Ibid.,  S.  840. 
10  Lehrbuch.  d.  pbysiol.  Cbem.,  S.  331. 


NON- STRIATED  MUSCLE.  389 

juice  obtained  by  pressing  the  muscles  of  the  Anodonta  and  which 
coagulates  immediately  at  +  45°  C.  or  within  24  hours  at  the  ordi- 
nary temperature.  Myosin  has  not  been  found  in  the  smooth 
muscles.  Heidenhain  and  Hellwig'  have  obtained  from  the 
smooth  muscles  of  a  dog  an  albuminous  body  which  coagulates  at 
-)-45°to49°  C.  and  which  is  analogous  to  musculin.  The  smooth 
muscles  contain  large  amounts  of  alkali  albuminates  besides  an  al- 
bumin coagulating  at  -|-  75°  C. 

Hcemoglohin  occurs  in  the  smooth  muscles  of  certain  animals, 
but  is  absent  in  others.  Creatin  has  been  found  by  Lehmann.^ 
According  to  Fkemt  and  VALEN"CiEN]srEs/  the  muscles  of  the 
Ceplialopods  contain  ^a?<rm  besides  creatinin  {creatin?).  Of  the 
non-nitrogenous  substances,  glycogen  and  lactic  acid  have  been 
found  without  doubt.  The  mineral  constituents  show  the  remark- 
able fact  that  the  sodium  combinations  exceed  the  potassium  com- 
binations.* 

>  Nasse,  1.  c,  S.  339. 

« Ibid. 

»  Cited  from  Kuhne's  Lehrbuch,  S.  333. 


CHAPTEE  XII. 

-BRAIN  AND  NERVES. 

On  account  of  the  difficulty  of  making  a  mechanical  separation 
and  isolation  of  the  different  tissue-elements  of  the  nervous  central 
organ  and  the  nerves,  we  must  resort  to  a  few  microchemical  re- 
actions, chiefly  to  qualitative  and  quantitative  investigations  of  the 
different  parts  of  the  brain,  in  order  to  study  the  different  chemical 
composition  of  the  cells  and  the  nerve-tubes.  The  chemical  investi- 
gation of  this  part  is  accompanied  with  the  greatest  difficulty ;  and 
although  our  knowledge  of  the  chemical  composition  of  the  brain 
and  nerves  has  been  somewhat  extended  by  the  investigations  of 
modern  times,  still  we  must  admit  that  this  chapter  is  as  yet  one 
of  the  most  obscure  and  complicated  in  physiological  chemistry. 

Proteids  of  different  kinds  have  been  shown  to  be  chemical  con- 
stituents of  the  brain  and  nerves.  A  part  of  these  are  insoluble  in 
water  and  dilute  neutral-salt  solutions,  and  part  are  soluble  therein. 
Among  the  latter  we  find  albumin  and  globulin.  Nucleoalbumin, 
which  is  often  considered  as  an  alkali  albuminate,  also  occurs. 
Hallibueton  '  found  two  globulins  in  the  brain,  one  of  which 
coagulates  at  47-50°  C.  and  the  other  at  70°  C.  He  found  in  the^ 
gray  matter  a  nucleoalbumin  which  coagulated  at  55-60°  0.  and 
contained  0.5^  phosphorus.  It  seems  unquestionable  that  the 
albuminous  bodies  belong  chiefly  to  the  gray  substance  of  the 
brain  and  to  the  axis-cylinders.  The  same  remarks  apply  to 
nuclein,  which  v.  Jacksch  "  found  in  large  quantities  in  the  gray 
substance.  Neuroheratin  see  page  49),  which  was  first  detected  by 
KuHNE,  and  which   partly  forms  the  neuroglia,  and  which  as  a 

'  On  the  Chemical  Physiolog}^  of  the  Animal  Cell.    King's  College,  London, 
Physiological  Laboratory.     Collected  Papers,  No.  1,  1893. 
»Pfliiger's  Arch.,  Bd.  13. 

390 


THE  BRAIN.  391 

double  sheath  envelops  the  outside  of  the  nerve  medulla  under 
Schwann's  sheath  and  the  inner  axis-cylinders,  chiefly  occurs 
in  the  white  substance  (Kuhne  and  Chittenden/  Baumstark).' 

The  phosphorized  substance  protagon  must  be  considered  as  one 
of  the  chief  constituents,  perhaps  the  only  constituent  (Baum- 
stark),  of  the  white  substance.  This  last-mentioned  substance,  if 
we  keep  for  the  present  to  the  most  carefully  studied  j^rotagon 
— because  there  are  perhaps  several  different  protagons — yields  as 
decomposition  products  lecithin,  fatty  acids,  and  a  nitrogenous 
substance,  cerehrin  ;  this  last  probably  does  not  occur  preformed  in 
the  brain,  but  is  more  likely  a  product  of  transformation.  That 
lecithin  also  is  pre-existent  in  the  brain  and  nerves  can  hardly  be 
doubted.  The  investigations  thus  far  made  have  not  shown 
decidedly  whether  it  is  more  abundant  in  the  gray  or  the  white 
substance.  Fatty  acids  and  neutral  fats  may  be  prepared  from  the 
brain  and  nerves;  but  as  these  may  be  readily  derived  from  a  decom- 
position of  lecithin  and  protagon,  which  exist  in  the  fatty  tissue 
between  the  nerve- tubes,  it  is  difficult  to  decide  what  part  the  fatty 
acids  and  neutral  fats  play  as  constituents  of  the  real  nerve-substance. 
Cholesterin  is  also  found  in  the  brain  and  nerves,  a  part  free  and  a 
part  in  chemical  combination  of  which  we  know  nothing  about 
(Baumstark).  Cholesterin  seems  to  occur  in  greater  abundance 
in  the  white  substance.  Besides  these  substances  the  nerve  tissue, 
especially  the  white  substance,  contains  doubtless  a  number  of  other- 
constituents  not  well  known,  and  among  which  are  several  containing 
phosphorus.  Thudichum  asserted  that  he  had  isolated  a  number 
of  phosphorized  substances  from  the  brain  which  he  divided  into 
three  principal  groups  :  Tcepalines,  myelines,  and  lecitkmes.  But 
thus  far  this  assertion  has  not  been  confirmed  by  other  in- 
vestigators. 

By  allowing  water  to  act  on  the  contents  of  the  medulla,  round 
or  oblong  double-contoured  drops  or  fibres,  not  unlike  double-con- 
toured nerves,  are  formed.  This  remarkable  formation,  which  can. 
also  be  seen  in  the  medulla  of  the  dead  nerve,  has  been  called 
"myeline  forms,"  and  they  were  formerly  considered  as  produced 
from  a  special  body,  "myeline."  Myeline  forms  may,  however,  b& 
obtained  from  other  bodies,  such  as  impure  protagon,  lecithin,  fat, 
and  impure  cholesterin,  and  they  depend  on  a  decomposition  of  the 

»  Zeitschr.  f .  Biologic,  Bd.  26. 

*  Zeitschr.  f.  pliysiol.  Chem.,  Bd.  9. 


31)2  BRAIN  AND  NERVES. 

constituents  of  the  medulla.  According  to  Gad  and  Hetmaxs  ' 
myeline  is  lecithin  in  a  free  condition  or  in  loose  chemical  com- 
bination. 

The  extractive  bodies  seem  to  be  almost  the  same  as  in  the  mus- 
cles. We  find  creatifi,  which  may,  however,  be  absent  (Baum- 
stark),  xanthin  bases,  inosit,  lactic  acid  (also  fermentation  lactic 
acid),  uric  acid,  jecorin  (according  to  Baldi,^  in  the  human  brain), 
and  neuridin,  C^Hj^N^,  discovered  by  Briegee'  and  which  is 
most  interesting  because  of  its  appearance  in  the  putrefaction  of 
animal  tissues  or  in  cultures  of  the  typhoid  bacillus.  Under  patho- 
logical conditions  leucin  and  urea  have  been  found  in  the  brain. 
Urea  is  also  a  physiological  constituent  of  the  brain  of  cartilaginous 
fishes. 

Of  the  above-mentioned  constituents  of  the  nerve-substance 
protagon  and  its  decomposition  products,  the  cerebrins  or  cerebro- 
sides,  must  be  specially  described. 

Protagon.  This  body,  which  was  discovered  by  Liebeeich,  is 
a  nitrogenized  and  phosphorized  substance  whose  elementary  com- 
position, according  to  Gamgee  and  Blai^kexhoex,*  is  C  66.39, 
H  10.69,  N  2.39,  and  P  1.068  percent.  Baumstaek  '  andEuppEL" 
obtained  the  same  figures,  while  Liebeeich  '  found  an  average  of 
2.80^  N  and  1.23^  P.  Kossel  and  Feeytag,^  who  obtained  still 
higher  figures  for  the  nitrogen,  namely,  3.25^,  and  somewhat  lower 
figures  for  the  phosphorus,  0.97^,  found  some  sulphur,  an  average 
of  0.51^,  regularly  in  the  protagon.  Euppel  also  found  some  sul- 
phur, but  in  such  small  quantity  that  he  considered  it  as  a  contami- 
nation. On  boiling  with  baryta-water  protagon  yields  the  decompo- 
sition products  of  lecithin,  namely,  fatty  acids,  glycerophosphoric 
acid,  and  cholin  (neurin  ?),  and  besides  this  also  cerebrin.  Kossel 
and  Urettag  found  that  protagon  not  only  yielded  cerebrin  in  its 
decomposition,  but  two  and  perhaps  indeed  three  cerebrosides  (see 
below),  namely  ceeebein,  keeasix  (homocerebrin),  and  encepha- 
lic.    Because  of  this  behavior,  and  also  because  of  the  varying 

'  Du  Bois-Reymond's  Arch.,  1890. 
^  Ibid.,  1887,  Supplbd. 

'  Brieger,  Ueber  Ptomaine.     Berlin,  1885  and  1886. 
*  Zeitschr.  f.  physiol.  Chem.,  Bd.  3. 
^  Ibid.,  Bd.  9. 

«  Zeitsclir.  f.  Biologie,  Bd.  31. 
'  Annal.  d.  Chem.  u.  Pharm.,  Bd.  134. 
.  8  Zeitschr.  f.  physiol.  Chem.,  Bd.  17. 


PROTAGON.  393 

elementary  composition  although  the  greatest  care  was  taken  in  the 
preparation,  Fkettag  considers  it  very  probable  that  there  are 
more  than  one  protagon. 

On  boiling  with  dilute  mineral  acids,  protagon  yields  among 
other  substances  a  reducing  carbohydrate.  On  oxidation  with 
nitric  acid  protagon  yields  higher  fatty  acids. 

Protagon  appears,  when  dry,  as  a  loose  white  powder.  It  dis- 
solves in  alcohol  of  85  vols,  per  cent  at  +  45°  C,  but  separates  on 
cooling  as  a  snow-white,  flaky  precipitate,  consisting  of  balls  or 
groups  of  fine  crystalline  needles.  It  decomposes  on  heating  even 
below  100°  C.  It  is  hardly  soluble  in  cold  alcohol  or  ether,  but 
dissolves  on  warming.  It  swells  in  little  water,  decomposes  partly. 
With  more  water  it  swells  to  a  gelatinous  or  pasty  mass,  which  with 
much  water  yields  an  opalescent  liquid.  On  fusing  with  saltpetre 
and  soda,  alkali  phosphates  are  obtained. 

Protagon  is  prepared  in  the  following  way  :  An  ox-brain  as 
fresh  as  possible,  with  the  blood  and  membranes  carefully  removed, 
is  ground  fine  and  then  extracted  for  several  hours  with  alcohol  of 
85  vols,  per  cent  at  +  45°  C,  filtered  at  the  same  temperature, 
and  the  residue  extracted  with  warm  alcohol  until  the  filtrate  does 
not  yield  a  precipitate  at  0°  C.  The  several  alcoholic  extracts  are 
cooled  to  0°  C.  and  the  precipitates  united  and  completely  extracted 
with  cold  ether,  which  dissolves  the  cholesterin  and  lecithin-like 
bodies.  The  residue  is  now  strongly  pressed  between  filter-paper 
and  allowed  to  dry  over  sulphuric  acid  or  phosphoric  anhydride. 
It  is  now  pulverized,  digested  with  alcohol  at  -f-  45°  C,  filtered  and 
slowly  cooled  to  0°  C.  The  crystals  which  separate  may  be  purified 
when  necessary  by  recrystallization. 

The  same  steps  are  taken  when  we  wish  to  detect  the  presence 
of  protagon. 

On  decomposing  protagon  or  the  protagons  by  the  gentle  action 
of  alkalies  we  obtain  as  cleavage  products,  as  above  stated,  one  or 
more  bodies,  which  Thudichum'  has  embraced  under  the  name 
cerehrosides.  The  cerebrosides  are  nitrogenous  substances  free  from 
phosphorus,  which  yield  a  reducing  variety  of  sugar  (galactose)  on 
boiling  with  dilute  mineral  acids.  On  fusing  with  potash  or  by 
oxidation  with  nitric  acid  they  yield  higher  fatty  acids,  palmitic  or 
stearic  acids.  The  cerebrosides  isolated  from  the  brain  are  cerebri n, 
kerasin,  and  encephalin.  The  bodies  isolated  by  Kossel  and  Frey- 
TAG  from  pus,  pyosin  and  pyogcnin,  also  belong  to  the  cerebrosides. 

'  Thudichum,  Grundziige  der  anatomisclien  und  klinischen  Chemie,  Berlin, 
1886. 


394  BRAIN  AND  NERVES. 

Cerebrin.  Under  this  name  W.  Muller  '  first  described  a  nitrog- 
enous substance,  free  from  phosphorus,  which  he  obtained  by  ex- 
tracting a  brain-mass,  which  had  been  previously  boiled  with  baryta- 
water,  with  boiling  alcohol.  Following  a  method  essentially  the 
same,  but  differing  somewhat,  Geoghegan^  prepared  from  the 
brain  a  cerebrin  with  the  same  properties  as  Muller's,  but  con- 
taining less  nitrogen.  According  to  Parous  '  the  cerebrin  isolated 
by  Geoghegan  as  well  as  by  Muller  consists  of  a  mixture  of 
three  bodies,  "cerebrin,^'  '' homocerebrin,"  and  "  encephalin." 
KossEL  and  Freytag  *  isolated  two  cerebrosides  from  protagon 
which  were  identical  with  the  cerebrin  and  homocerebrin  of  Par- 
ous. According  to  these  investigators  the  two  bodies  phrenosin 
and  kerasin  as  described  by  Thudiohum  seem  to  be  identical  with 
cerebrin  and  homocerebrin. 

Cerebrin,  according  to  Parous,  has  the  following  composition  : 
C  69.08,  H  11.47,  N  2.13,  0  17. 33^  which  corresponds  with  the 
analyses  made  by  Kossel  and  Frettag.  No  formula  has  been  given 
to  this  body.  In  the  dry  state  it  forms  a  pure  white,  odorless,  and 
tasteless  powder.  On  heating  it  melts,  decomposes  gradually,  smells 
like  burnt  fat,  and  burns  with  a  luminous  flame.  It  is  insoluble  in 
water,  dilute  alkalies,  or  baryta-water.  It  is  also  insoluble  in  cold 
alcohol  and  in  cold  or  hot  ether.  On  the  contrary,  it  is  soluble 
in  boiling  alcohol  and  separates  as  a  flaky  precipitate  on  cooling, 
and  this  is  found  to  consist  of  a  mass  of  balls  or  grains  on  micro- 
scopical examination.  Cerebrin  forms  an  insoluble  compound  with 
baryta  which  decomposes  by  the  action  of  carbon  dioxide.  Cere- 
brin dissolves  in  concentrated  sulphuric  acid,  and  on  warming  the 
solution  it  becomes  blood-red.  The  variety  of  sugar  split  off  on 
boiling  with  mineral  acids — the  so-called  brain-sugar — is,  according 
to  Thierfelder,^  galactose. 

Kerasin  (according  to  Thudiohum)  or  homocerebrin  (accord- 
ing to  Parous)  has  the  following  composition:  C  70.06,  H  11.60, 
N  2.23,  and  0  16.11^.  Enceplialin  has  the  composition  C  68.40, 
H  11.60,  N  3.09,  and  0  16.91^.  Both  bodies  remain  in  the 
mother  liquor  after  the  impure  cerebrin  has  precipitated  from  the 

>  Annial.  d.  Cliem.  u.  Pharm. ,  Bd.  105. 
'  Zeitschr.  f.  pliysiol.  Chem.,  Bd.  3. 

5  Ueber  einige  reue  Gehirnstoffe,  Inaug.-Diss.,  Leipzig,  1881. 
*  L.  c. 

6  Zeitschr.  f.  physiol.  Chem.,  Bd.  14. 


CEREBRINS  AND  NEURIDIN.  395 

warm  alcohol.  These  bodies  have  the  tendency  of  separating  as 
gelatinous  masses.  Kerasin  is  homologous  to  cerebrin,  but  dissolves 
more  easily  in  warm  alcohol  and  also  in  warm  ether.  It  may  be 
obtained  as  extremely  fine  needles.  Encephalin  is,  according  to 
Pakcus,  a  transformation  product  of  cerebrin.  In  perfectly  pure 
state  it  crystallizes  in  small  lamellaB.  It  swells  into  a  pasty  mass  in 
warm  water.  Like  cerebrin  and  kerasin,  it  yields  a  reducing  sub- 
stance (probably  galactose)  on  boiling  with  dilute  acid. 

The  cerebrins  are  generally  prepared  according  to  Muller's 
method.  The  brain  is  first  stirred  with  baryta-water  until  it  ap- 
pears like  thin  milk  and  then  it  is  boiled.  The  insoluble  parts  are 
removed,  pressed,  and  repeatedly  boiled  with  alcohol,  which  is  fil- 
tered while  boiling  hot.  The  impure  cerebrin  which  separates  on 
cooling  is  freed  from  cholesterin  and  fat  by  means  of  ether,  and 
then  purified  by  repeated  solution  in  warm  alcohol.  According  to 
Parous  this  repeated  solution  in  alcohol  is  continued  until  no 
gelatinous  separation  of  homocerebrin  or  encephalin  takes  place. 

According  to  Geoghegan's  method  the  brain  is  first  extracted 
with  cold  alcohol  and  ether  and  then  boiled  with  alcohol.  The  pre- 
cipitate which  separates  on  the  cooling  of  the  alcoholic  filtrate  is 
treated  with  ether  and  then  boiled  with  baryta-water.  The  insolu- 
ble residue  is  purified  by  repeated  solution  in  boiling  alcohol. 

The  cerebrin  may  also  be  obtained  from  other  organs  by  employ- 
ing the  above  methods.  The  quantitative  estimation,  when  such  is 
desired,  may  be  performed  in  the  same  way. 

KossEL  and  Freytag  prepare  cerebrin  from  protagon  by  sa- 
ponifying it  in  a  solution  in  methyl  alcohol  with  a  hot  solution 
of  caustic  baryta  in  methyl  alcohol.  The  precipitate  is  filtered  off 
and  decomposed  in  water  by  carbon  dioxide,  and  the  cerebrin  or 
cerebroside  extracted  from  the  insoluble  residue  by  hot  alcohol. 

Neuridin,  CsHiiISTj,  is  a  uon-poisonous  diamin  discovered  by  Brieger,  and 
which  was  obtained  by  him  in  the  putrefaction  of  meat  and  gelatine,  and  from 
cultures  of  the  typhoid  bacillus.  It  also  occurs  under  physiological  conditions 
in  the  brain,  and  as  traces  in  the  yolk  of  the  egg. 

Neuridin  dissolves  in  water,  and  yields  on  boiling  with  alkalies  a  mixture 
of  dimethylamin  and  trimethylamin.  It  dissolves  with  difficulty  in  amyl-alco- 
hol.  It  is  insoluble  in  ether  or  absolute  alcohol.  In  the  free  state  neuridin 
has  a  peculiar  odor,  suggesting  semen.  With  hydrochloric  acid  it  gives  a 
combination  crystallizing  in  long  needles.  With  platinic  chloride  or  gold 
chloride  it  gives  crystallizable  double  combinations  which  are  valuable  in  its 
preparation  and  detection. 

The  so-called  CORPUSCULA  amtlacea,  which  occur  on  the  upper  surface 
of  the  brain  and  in  the  pituitary  gland,  are  colored  more  or  less  pure  violet  by 
iodine  and  more  blue  by  sulphuric  acid  and  iodine.  They  consist,  perhaps,  of 
the  same  substance  as  certain  prostatic  calculi,  but  they  have  not  been  closely 
investigated. 


596  BRAIN  AND  NERVES. 

Quantitative  Composition  of  the  Brain.  The  quantity  of  water 
is  greater  in  the  gray  than  in  the  white  substance,  and  greater  in 
new-born  or  young  individuals  than  in  grown  ones.  The  brain  of 
the  fcetus  contains  879-936  p.  m.  water.  According  to  the  obser- 
vations of  Weisbach  '  the  amount  of  water  in  the  several  parts  of 
the  brain  (and  in  the  medulla)  varies  at  different  ages.  The  fol- 
lowing j&gures  are  in  1000  parts — A  for  men  and  B  for  women : 

20-30  Years.  30-50  Years.  50-70  Years.  70 -94  Years. 

1.  B.  ^.B^  A.  B?  X"  B. 

White  substance  of 

the  brain 695.6  682.9  683.1  703.1  701.9  689.6  726.1  722  0 

>Gray  ditto. 833.6  826.2  836.1  830.6  838.0  838.4  847.8  839.5 

Gyri 784.7  792.0  795  9  772.9  796.1  796.9  802.3  801,7 

Cerebellum 788.3  794.9  778.7  789.0  787.9  784.5  803.4  797.9 

Pons  varoli 734.6  740.3  725  5  722.0  720.1  714.0  727.4  724.4 

Medulla  oblongata.  744.3  740.7  732.5  729.8  722.4  730.6  736.2  733.7 

Quantitative  analyses  of  the  brain  have  also  been  made  by 
Peteowsky  ^  on  an  ox-brain  and  by  Baumstark  '  on  the  brain  of  a 
liorse.  In  the  analysis  of  Peteowsky  the  protagon  has  not  been 
considered,  and  all  organic,  phosphorized  substances  were  calcu- 
lated as  lecithin.  On  these  grounds  these  analyses  are  not  of  much 
value  from  a  certain  standpoint.  In  Baumstark's  analyses  the 
gray  and  the  white  substance  could  not  be  sufficiently  separated, 
and  these  analyses,  on  this  account,  show  partly  an  excess  of  white 
and  partly  an  excess  of  gray  substance;  nearly  one  half  of  the 
•organic  bodies,  chiefly  consisting  of  bodies  soluble  in  ether,  could 
not  be  exactly  analyzed.  Neither  of  these  analyses  gives  sufficient 
explanation  of  the  quantitative  composition  of  the  brain. 

The  analyses  made  up  to  the  present  time  give,  as  above  stated, 
.an  unequal  division  of  the  organic  constituents  in  the  gray  and 
white  substance.  In  the  analyses  of  Petrowsky  the  quantity  of 
proteids  and  gelatin-forming  substances  in  the  gray  matter  was 
somewhat  more  than  one  half,  and  in  the  white  about  one  quarter, 
of  the  solid  organic  substances.  The  quantity  of  cholesterin  in 
the  white  was  about  one  half,  and  in  the  gray  substance  about  one 
fifth,  of  the  solid  bodies.  A  greater  quantity  of  soluble  salts  and 
extractive  bodies  was  found  in  the  gray  substance  than  in  the  white 
(Baumstark).  The  following  analyses  of  Baumstark  give  the 
most  important  known  constituents  of  the  brain  calculated  in  1000 

1  Cited  from  K.  B.  Hofmann's  Lebrb.  d.  Zoocbemie  (Wien,  1876),  S.  131. 

"  Pflilger's  Arch  ,  Bd.  7. 

3  Zeitschr.  f.  physiol.  Cbem.,  Bd.  9. 


COMPOSITION  OF  THE  BRAIX.  397 

parts  of  the  fresh,  moist  brain.    A  represents  chiefly  the  white,  and 
B  chiefly  tlie  gray,  substance. 

A.  B. 

Water 695.35  769.97 

Solids 304.65  230. Oii 

Protagon 25.11  10.80 

Insoluble  proteid  and  connective  tissue 50.02  60.7& 

Cholesterin,  free 18. 19  6.30 

combined 26.96  17.51 

Nuclein 2.94  1.99 

Neurokeratin 18.93  10.43 

Mineral  bodies 5.23  5.63 

The  remainder  of  the  solids  probably  consists  chiefly  of  lecithin 
and  other  jjhosphorized  bodies.  Of  the  total  amount  of  phosphorus 
15-20  p.  m.  belongs  to  the  nuclein,  50-60  p.  m.  to  the  protagon, 
150-160  p.  m,  to  the  ash,  and  770  p.  m.  to  the  lecithin  and  the 
other  phosphorized  organic  substances. 

The  quantity  of  neurokeratin  in  the  nerves  and  in  the  different 
parts  of  the  brain  has  been  carefully  determined  by  Kuhne  and 
Chittenden.'  They  found  3.16  p.  m.  in  the  plexus  brachialis, 
3.12  p.  m.  in  the  edge  of  the  cerebellum,  23.434  p.  m.  in  the  white 
substance  of  the  cerebrum,  25.72-29.02  p.  m.  in  the  white  sub- 
stance of  the  corpus  callosum,  and  3.27  p.  m.  in  the  gray  substance 
of  the  edge  of  the  cerebrum  (when  free  as  possible  from  white  sub- 
stance). The  white  is  very  considerably  richer  in  neurokeratin 
than  the  peripheric  nerves  or  the  gray  substance.  According  to 
Griffiths  '^  neurochitin  replaces  neurokeratin  in  insects  and 
Crustacea,  the  quantity  of  the  first  being  10.6-12  p.  m. 

The  quantity  of  mineral  constituents  in  the  brain  amounts  to 
2.95-7.08  p,  m.  according  to  Geoghegan.'  He  found  in  1000 
parts  of  the  fresh,  moist  brain  0.43-1.32  CI,  0.956-2.016  PO^, 
0.244-0.796  CO,,  0.102-0.220  SO,,  0.01-0.098  re,(POJ„  0.005- 
0.022  Ca,  0.016-0.072  Mg,  0.58-1.778  K,  0.450-1.114  Na.  The 
gray  substance  yields  an  alkaline  ash,  the  white  an  acid  ash. 

Appendix. 

The  Tissue  and  Fluids  of  the  Eye. 

The  retina  contains  in  all  865-899.9  p.  m.  water,  57.1-84.5 
p.  m.  proteid  bodies — myosin,  albumin,  and  mucin  (?),  9.5-28.9 
p.    m.   lecithin,    and  8.2-11.2   p.    m.  salts    (Hoppe-Seyler   and 

'  Zeitscbr.  f.  Biologie,  Bd.  26. 

*  Compt.  rend..  Tome  115. 

^  Zeitscbr.  f.  pbvsiol.  Cbem.,  Bd.  3. 


398  BRAIN  ANB  NEBVES. 

Cahn').  The  mineral  bodies  consist  of  422  p.  m.  Na,HPO^  and 
352  p.  m.  NaCl. 

Those  bodies  which  form  the  different  segments  of  the  rods  and 
cones  have  not  been  closely  studied,  and  the  greatest  interest  is 
therefore  connected  with  the  coloring  matters  of  the  retina. 

Visual  purple,  also  called  rliodopsm,  erythr opsin ^  or  visual 
EED,  is  the  pigment  of  the  rods.  Boll  *  observed  in  1876  that  the 
layer  of  rods  in  the  retina  during  life  had  a  purplish-red  color 
which  was  bleached  by  the  action  of  light.  Kuhn'b  ^  showed  later 
that  this  red  color  might  remain  for  a  long  time  after  the  death  of 
the  animal  if  the  eye  was  protected  from  daylight  or  investigated 
by  a  sodium  light.  Under  these  conditions  it  was  also  possible  to 
Isolate  and  closely  study  this  substance. 

Visual  red  (Boll)  or  visual  purple  (Kuhne)  has  become  known 
mainly  by  the  investigations  of  Kuhn"E.  The  pigment  occurs 
chiefly  in  the  rods  and  only  in  their  outer  parts.  In  animals  whose 
retina  has  no  rods  the  visual  purple  is  absent,  and  is  also  neces- 
sarily absent  in  the  macula  lutea.  In  a  variety  of  bat  [rhinolopJius 
Jiipposideros),  in  hens,  pigeons,  and  new-born  rabbits,  no  visual 
purple  has  been  found  in  the  rods. 

A  solution  of  visual  purple  in  water  which  contains  2-5^ 
crystallized  bile,  which  is  the  best  solvent  for  it,  is  purple-red  in 
color,  quite  clear,  and  not  fluorescent.  On  evaporating  this  solu- 
tion in  vacuo  we  obtain  a  residue  similar  to  ammonium  carminate 
which  contains  violet  or  black  grains.  If  the  above  solution  is 
dialyzed  with  water,  the  bile  diffuses  and  the  visual  purple  separates 
as  a  violet  mass.  Under  all  circumstances,  even  when  still  in  the 
retina,  the  visual  purple  is  quickly  bleached  by  direct  sunlight, 
and  with  diffused  light  with  a  rapidity  corresponding  to  the  in- 
tensity of  the  light.  It  passes  from  red  and  orange  to  yellow. 
Eed  light  bleaches  the  visual  purple  slowly  ;  the  ultra-red  light 
does  not  bleach  it  at  all.  A  solution  of  visual  purple  shows  no 
special  absorption-bands,  but  only  a  general  absorption  which 
extends  from  the  red  side,  beginning  at  D,  to  the  line  G.  The 
strongest  absorption  is  found  at  E. 

Visual  purple  when  heated  to  52°-53°  C.  is  destroyed  after  several 

'  Zeitschr    f.  Physiol.  Chein. ,  Bd.  5. 

2  Monatsschr.  d.  Berl.  Akad.,  12  Nov.  1876. 

^  The  investigations  of  Kuhne  and  his  pupils  Ewald  and  Ayres  on  the  vis- 
ual purple  will  be  found  in  Untersuchungen  aus  dem  physiol.  Institut  der 
Universitat  Heidelberg,  Bdd.  1  und  2. 


VISUAL   PURPLE.  390 

hours,  and  almost  instantly  when  heated  to  +  76°  C.  It  is  also 
destroyed  by  alkalies,  acids,  alcohol,  ether,  and  chloroform.  On  the 
contrary,  it  resists  the  action  of  ammonia  or  alum  solution. 

As  the  visual  purple  is  easily  destroyed  by  light,  it  must  there- 
fore also  be  regenerated  during  life.  Kuhne  has  also  found  that 
the  retina  of  the  eye  of  the  frog  becomes  bleached  when  exposed  for 
a  long  time  to  strong  sunlight,  and  that  its  color  gradually  returns 
when  the  animal  is  placed  in  the  dark.  This  regeneration  of  the 
visual  purple  is  a  function  of  the  living  cells  in  the  layer  of  the 
pigment-epithelium  of  the  retina.  This  may  be  inferred  from  the 
fact  that  a  detached  piece  of  the  retina  which  has  been  bleached 
by  light  may  have  its  visual  purple  restored  if  the  detached  piece 
of  the  retina  be  carefully  laid  on  the  chorioidea  having  layers  of 
the  pigment-epithelium  attached.  Tlie  regeneration  has,  it  seems, 
nothing  to  do  with  the  dark  pigment,  the  melanin  or  fuscin,  in  the 
epithelium-cells.  A  partial  regeneration  seems,  according  to 
KtJHXE,  to  be  possible  in  the  completely  removed  retina.  On  ac- 
count of  this  property  of  the  visual  purple  of  being  bleached  by 
light  during  life  we  may,  as  Kuhne  has  shown,  under  special  con- 
ditions and  by  observing  special  precautions,  obtain  after  death  by 
the  action  of  intense  light  or  more  continuous  light  the  picture  of 
bright  objects,  such  as  windows  and  the  like — so-called  optograms. 

The  physiological  importance  of  visual  purple  is  unknown.  It 
follows  that  the  visual  purple  is  not  essential  to  sight,  since  it  is 
absent  in  certain  animals  and  also  in  the  cones. 

Visual  purple  must  always  be  prepared  exclusively  in  a  sodium 
light.  It  is  extracted  from  the  net  membrane  by  means  of  a  watery 
solution  of  crystallized  bile.  The  filtered  solution  is  evaporated  in 
vacuo  or  dialyzed  until  the  visual  purple  is  separated. 

To  prepare  a  visual-purple  solution",  perfectly  free  from  haemo- 
globin, KuHNE '  suggests  to  precipitate  it  from  it  solution  in 
bile  by  Mg  SO^  in  substance,  or  to  treat  the  retina,  which  has 
been  previously  hardened  by  alum  and  then  lixiviated  with  water 
and  10^  NaCl  solution,  with  bile. 

The  pigments  of  the  cones.  In  the  inner  segments  of  the  cones  of  birds, 
reptiles,  and  fishes  a  small  fat-globule  of  varying  color  is  found.  KtiHNE'''  has 
isolated  from  this  fat  a  green,  a  yellow,  and  a  red  pigment  called  respectively 
cMrn'ophan,  xanthophan,  and  rhodophan. 

1  Zeitschr.  f.  Biologic,  Bd.  32. 

'  Kiihne,  Die  nichtbestandigen  Farben  der  Netzhaut.  Untersuch.  aus  dem 
physiol.  Institut  Heidelberg,  Bd.  1,  S.  341. 


400  BRAIN  AND  NERVES. 

The  dark  pigment  of  the  epithelium-cells  of  the  net  membrane,  which  was 
formerly  called  melanin,  but  since  named  fuscin  by  KtJhne  and  May,'  dis- 
solves in  concentrated  caustic  alkalies  or  concentrated  sulphuric  acid  on  warm- 
ing, but,  like  melanins  in  general  (see  Chapter  XVI),  has  been  little  studied. 
The  pigment  occurring  in  the  pigment-cells  of  the  chorioidea  seems  to  be  iden- 
tical with  the  fuscin  of  the  retina. 

The  vitreous  humor  is  often  considered  as  a  variety  of  gelatinous 
tissue.  The  membrane  consists,  according  to  C.  Morner/  of  a 
gelatine-forming  substance.  The  fluid  contains  a  little  proteid  and 
a  mucoid,  Jiyalomucoid,  which  was  first  shown  by  Morker,  and 
which  is  not  precipitated  by  acetic  acid.  This  contains  12.27^  jST 
and  1.19^  S.  Among  the  extractives  we  find  a  little  urea  accord- 
ing to  Picard"  5  p.m.,  according  to  Rahlmaistn^  0.64  p.  m. 
Pautz  ^  found  besides  some  urea  also  paralactic  acid,  and,  in  con- 
firmation of  the  statements  of  Chabbas,  Jesfer,  and  Kuhn",  also 
glucose  in  the  vitreous  humor  of  oxen.  The  reaction  of  the  vitreous 
humor  is  alkaline,  and  the  quantity  of  solids  amounts  to  about 
11  p.  m.  The  quantity  of  mineral  bodies  is  about  9  p.  m.,  and 
the  albuminous  bodies  0.7  jo.  m.  In  regard  to  the  aqueous  humor 
see  page  195. 

The  crystalline  lens.  That  substance  which  forms  the  capsule 
of  the  lens  ;  has  been  recently  investigated  by  C.  Morner.  It 
belongs,  according  to  him,  to  a  special  group  of  protein,  which  are 
called  me7niramns.  The  membranin  bodies  are  insoluble  at  the 
ordinary  temperature  in  water,  salt  solutions,  dilute  acids  and 
alkalies,  and,  like  the  mucins,  yield  a  reducing  substance  on  boiling 
with  dilute  mineral  acids.  They  contain  sulphur,  which  blackens 
lead.  The  membranins  are  colored  a  very  beautiful  red  by  MiL- 
lon's  reagent,  but  give  no  characteristic  reaction  with  concen- 
trated hydrochloric  acid  or  Adamkiewicz's  reagent.  They  are 
dissolved  with  great  difficulty  by  pepsin-hydrochloric  acid  or  trypsin 
solution.  They  are  dissolved  by  dilute  acids  and  alkalies  in  the 
warmth.  Membranin  of  the  capsule  of  the  lens  contains  14.10^ 
N  and  0.83^  S,  and  is  a  little  less  soluble  than  that  from  Des- 
oemets  membrane. 

The  chief  mass  of  the  solids  of  the  crystalline  lens  consists  of 

'  Kuhne,  ibid.,  Bd.  2,  S.  324. 
«  Zeitschr.  f.  physiol.  Chem.,  Bd.  18. 
2  Gamgee's  Physiol.  Chem.,  p.  454. 
*  Maly's  Jahresber.,  Bd.  6,  S.  219. 
s  Zeitschr.  f.  Biologie,  Bd.  31. 


PROTEIDS  OF  THE  CRYSTALLINE  LENS.  401 

proteids,  whose  nature  has  been  investigated  by  C.  Morner.  '  Some 
of  these  proteids  are  insoluble  in  dilute  salt  solution,  and  others 
soluble  therein. 

The  Insoluble  Proteid.  The  lens-fibres  consist  of  a  proteid  sub- 
stance which  is  insoluble  in  water  and  salt  solution  to  which 
MoRNER  has  given  the  name  albumoid.  It  dissolves  readily  in 
very  dilute  acids  or  alkalies.  Its  solution  in  caustic  potash  of  0.1^ 
is  very  similar  to  an  alkali-albuminate  solution,  but  coagulates  at 
about  50°  C.  on  nearly  complete  neutralization  and  addition  of  8^ 
NaCl.  Albumoid  has  the  following  composition:  C  53.12,  H  6.8, 
N  16.62,  and  S  0.79^.  The  lens-fibres  themselves  contain  16.61^  N 
and  0.77^  S.  The  inner  parts  of  the  lens  are  considerably  richer  in 
albumoid  than  the  outer.  The  quantity  of  albumoid  in  the  entire 
lens  amounts  on  an  average  to  about  48^  of  the  total  weight  of 
proteids  of  the  lens. 

The  Soluble  Proteid  consists,  exclusive  of  a  very  small  quantity 
of  ALBUMIN,  of  two  globulius,  a-  and  /J-crystallin.  These  two 
globulins  differ  from  each  other  in  this  manner :  <a'-crystallin  con- 
tains 16.68^  N  and  0.56^  S;  /5-crystallin,  on  the  contrary,  17.04^  N 
and  1.27^  S.  The  first  coagulates  at  about  72°  C.  and  the  other  at 
63°  C.  Besides  this,  /5-crystallin  is  precipitated  from  salt-free 
solution  with  greater  difficulty  by  acetic  acid  or  carbon  dioxide. 
These  globulins  are  not  precipitated  by  an  excess  of  NaCl  at  either 
the  ordinary  temperature  or  30°  C.  Magnesium  or  sodium  sul- 
phate in  substance  precipitates  both  globulins,  on  the  contrary,  at 
30°  C.  These  two  globulins  are  not  equally  divided  in  the  mass  of 
the  lens.  The  quantity  of  a-crystallin  diminishes  in  the  lens  from 
without  inwards,  /^-crystallin,  on  the  contrary,  from  within  out- 
wards. 

ABbchamp'  distiuguisLes  the  two  following  albuminous  bodies  in  the 
watery  extiact  of  the  crystalline  lens  :  phacozymase,  which  coagulates  at 
4"  55°  C. ,  and  contains  a  diastatic  enzyme,  and  has  a  specific  rotatory  power  of 
{^(X)j  —  —  41°,  and  the  crystalbamin.  with  a  specific  rotatory  power  of 
{c^j  =  —  80 -.3.  From  the  residue  of  the  lens,  which  was  insoluble  in  water, 
Bechamp  extracted,  by  means  of  hydrochloric  acid,  an  albuminous  body  having 
a  specific  rotatory  power  of  {a)j  ==  —  80°. 2  which  he  called  crystaljibrin. 

The  lens  does  not  seem  to  contain  any  proteid  bodies  which 

coagulate  spontaneously  like   fibrinogen.     That  cloudiness  which 

appears  after  death  depends,  according  to  Kunhe,'  upon  the  un- 

'  Zeitschr.  f.  physiol.  Chem.,  Bd.  18.  This  contains  also  the  pertinent  lit- 
erature. 

»Compt.  rend.,  Bd.  90. 

'  Lehrbuch  d.  physiol.  Chem.,  S.  405. 


402  BRAIN  AND  NERVES. 

equal  changing  of  the  concentration  of  the  contents  of  the  lens- 
tubes.  This  change  is  produced  by  the  altered  ratio  of  diffusion. 
A  cloudiness  of  the  lens  may  also  be  produced  in  life  by  a  rapid 
removal  of  water,  as,  for  example,  when  a  frog  is  plunged  into  a 
salt  or  sugar  solution  (Kunde  ').  The  appearance  of  cloudiness  in 
diabetes  has  been  attributed  by  some  to  the  removal  of  water.  The 
views  on  this  subject  are,  however,  contradictory. 

The  average  results  of  four  analyses  made  by  Laptschiksky  "  of 
the  lens  of  oxen  are  here  given,  calculated  in  parts  per  1000 : 

Proteids 349.3 

Lecithin • 2.3 

Cholesterin 2.2 

Fat 2.9 

Soluble  salts 5.3 

Insoluble  salts 2.3 

In  cataract  the  amount  of  proteid  is  diminished  and  the  amount 
of  cholesterin  increased. 

The  quantity  of  the  different  proteids  in  the  fresh  moist  lens  of 

oxen  is  as  follows,  according  to  Mornee*  : 

Albumoid  (lens-fibres) 170  p.  m. 

/J-crystallin 110     " 

a-ciystallin 68     " 

Albumin 2     " 

The  corneal  tissue  has  been  previously  treated  of  (page  348). 
The  sclerotic  has  not  been  closely  investigated,  and  the  choroid  coat 
is  chiefly  of  interest  because  of  the  coloring  matter,  melanin,  it  con- 
tains (see  Chap.  XVI). 

Tears  consist  of  a  water-clear,  alkaline  fluid  of  a  saltish  taste. 
According  to  the  analyses  of  Leech  '  they  contain  983  p.  m.  water, 
18  p.  m.  solids,  with  5  p.  m.  albumin  and  13  p.  m.  NaCl. 

The  Fluids  of  the  Inner  Ear. 

The  perilymph  and  endolymph  are  alkaline  fluids  which,  besides 
salts,  contain — in  the  same  amounts  as  in  transudations — traces  of 
albumin,  and  in  certain  animals  (codfish)  also  mucin.  The  quantity 
of  mucin  is  greater  in  the  perilymph  than  in  the  endolymph. 

Otoliths  contain  745-795  p.  m.  inorganic  substance,  which  con- 
sists chiefly  of  crystallized  calcium  carbonate.  The  organic  sub- 
stance is  very  like  mucin. 

'  Cited  from  Kiibne,  1.  c. 

«  Pfluger's  Arch.,  Bd.  13. 

»L.  c. 

^  Cited  from  Gorup-Besanez,  Lebrb.  d.  pbysiol  Chem.,  4.  Aufl.,  S.  401. 


CHAPTER  XIII. 

ORGANS   OF   GENERATION. 

(a)  Male  Generative  Secretions. 

The  testis  liave  been  little  investigated  chemically.  We  find 
in  the  testis  of  animals  proteid  bodies  of  different  kinds,  seralbu- 
min, alkali  alhuminate  (?),  and  an  albuminous  body  related  to 
RoviDAS'  hyaline  suhstance,  also  leucin,  tyrosi7i,  creatin,  xantliin 
bases,  cliolesterin,  lecithin^  inosit,  and/a/f.  In  regard  to  the  occur- 
rence of  glycogen  the  statements  are  somewhat  contradictory. 
Daeeste'  found  in  the  testis  of  birds  starch-like  granules,  which 
were  colored  blue  with  difficulty  by  iodine. 

The  semen  as  ejected  is  a  white  or  whitish-yellow,  viscous, 
sticky  fluid  of  a  milky  appearance,  with  whitish,  non-transparent 
lumps.  The  milky  appearance  is  due  to  spermatozoa.  Semen  is 
heavier  than  water,  contains  albumin,  has  a  neutral  or  faintly 
alkaline  reaction  and  a  peculiar  specific  odor.  Soon  after  ejection 
semen  becomes  gelatinous,  as  if  it  were  coagulated,  but  afterwards 
becomes  more  fluid.  When  diluted  with  water  white  flakes  or 
shreds  separate  (Henle's  fibrin).  According  to  the  analyses  of 
Vauquelin''  human  semen  contains  900  p.  m.  water  and  100 
p.  m.  solids,  with  60  p.  m.  organic  and  40  p.  m.  inorganic  sub- 
stance, of  which  30  p.  m.  is  calcium  phosphate.  Among  the 
albuminous  bodies  Posner'  claims  that  propeptone  occurs  even  in 
the  absence  of  the  spermatozoa. 

The  semen  in  the  vas  deferens  differs  chiefly  from  the  ejected 
semen  in  that  it  is  without  the  peculiar  odor.  This  last  depends  on 
the  admixture  with  the  secretion  of  the  prostate.     This  secretion, 

'  Compt.  rend. ,  Tome  74. 

*  Cited  from  Lelimann's  Lehrb.   d.  pbysiol.   Cbem,   (Leipzig,  1853),    Bd.  2, 
S.  303 

8  Berlin,  klin.  Wochenschr. ,  1888,  No.  21,  and   Centralbl.  f.  d.    med.  Wis- 
senscli.,  1890,  S.  497. 

403 


404  ORGANS   OF  GENERATION. 

according  to  Iversen/  Las  a  milky  appearance  and  ordinarily  an 

alkaline  reaction,  yery  rarely  a  neutral  one,  contains  small  amounts 

of  proteids  and  mineral  bodies,  especially  NaCl.     Besides  these  it 

contains  a  crystalline  combination  of  phosphoric  acid  with  a  base, 

CjHj^lSr.     This  combination  has  been  called  Bottcher's  spermine 

crystals,  and  it  is  claimed  that  the  specific  odor  of  the  semen  is  due 

to  a  partial  decomposition  of  these  crystals. 

The  crystals  which  appear  on  slowly  evaporating  the  semen,. 

and  which   are  also  observed  in  anatomical  preparations  kept  in 

alcohol  and  in  desiccated  egg-albumin,  are  identical,  according  to 

ScHEEiiirEE,  with  Charcot's  crystals  found  in  the  blood,  and  in 

the    lymphatic    glands    in    leucaemia.     They    are,    according    to 

SoHREiNER,^  a  combination  of  phosphoric  acid  with  a  base,  sjjer- 

min,  CjH.N,  which  he  discovered. 

Spermin.  The  views  in  regard  to  the  nature  of  this  base  are  not  unanimous. 
According  to  the  investigations  of  Ladenbukg  and  Abel  '  it  is  not  improba- 
ble that  spermin  is  identical  with  ethylenimin,  but  this  identity  is  disputed  by 
Majert  and  A.  Schmfdt,*  andalso  by  Poehl.*  The  compound  of  spermin 
with  phosphoric  acid — Bottcher's  spermine  crystals — is  insoluble  in  alcohol, 
ether,  and  chloroform,  soluble  with  diiEculty  in  cold  water  but  more  readily  in 
hot  water,  and  easily  soluljle  in  dilute  acids  or  alkalies,  also  alkali  carbonates 
and  ammonia.  The  base  is  precipitated  by  tannic  acid,  mercuric  chloride, 
gold  chloride,  platinic  chloride,  potassium-bismuthic  iodide,  and  phospho- 
tungstic  acid.  Spermin  has  a  tonic  action,  and  according  to  Poehl*  it  has  a 
marked  action  on  the  oxidation  processes  of  the  animal  body. 

The  spermatozoa  show  a  great  resistance  to  chemical  reagents 
in  general.  They  do  not  dissolve  completely  in  concentrated  sul- 
phuric acid,  nitric  acid,  acetic  acid,  nor  in  boiling-hot  soda  solu- 
tions. They  are  soluble  in  a  boiling-hot  caustic-potash  solution. 
They  resist  putrefaction,  and  after  drying  they  may  be  obtained 
again  in  their  original  form  by  moistening  them  with  a  1^  com- 
mon-salt solution.  By  careful  heating  and  burning  to  an  ash  the 
shape  of  the  spermatozoa  may  be  seen  in  the  ash.  The  quantity  of 
ash  is  about  50  p.  m.  and  consists  mainly  (f )  of  potassium  phos- 
phate. 

The  spermatozoa  show  well-known  movements,  but  the  cause 
of  this  is  not  known.  This  movement  may  continue  for  a  very  long 
time,  as  under  some  conditions  it  may  be  observed  for  several  days 

'  Nord.  med.  Ark.,  Bd.  6;  also  Maly's  Jahresber.,  Bd.  4,  S.  358. 
»  Annal.  d.  Chem.  u.  Pharm.,  Bd.  194. 

*  Ber.  d.  deutsch.  chem.  Qesellsch.,  Bd.  21. 

*  Ibid.,  Bd.  24. 

'  Compt.  rend.,  Tome  115. 

*  Berlin,  klin.  Wochenschr.,  1893,  No.  36. 


SPERMATOZOA.  405 

in  the  body  after  death,  and  in  the  secretion  of  the  uterus  longer 
than  a  week.  Acid  liquids  stop  these  movements  immediately;  they 
are  also  destroyed  by  strong  alkalies,  especially  ammoniacal  liquids, 
also  by  distilled  water,  alcohol,  ether,  etc.  The  movements  con- 
tinue for  a  longer  time  in  faintly  alkaline  liquids,  especially  in 
alkaline  animal  secretions,  and  also  in  properly  diluted  neutral  salt- 
solutions. 

xVccording  to  the  investigations  of  Miescher,'  there  are  lecithin 
and  nuclein,  but  no  cerebrin,  in  the  spermatozoa  of  bulls.  The 
head  of  the  spermatozoa  contains  nuclein,  which  forms  probably 
the  outer  part  of  the  head;  alhumin,  which  forms  the  contents  of 
the  head;  and  lastly  a  substance  rich  in  sulphur  Avhich  has  not 
"been  studied.  The  tail  dissolves  in  gastric  juice  after  continuous 
digestion,  and  seems  to  consist  of  proteids  or  allied  bodies  which 
show  a  variable  resistance  towards  pepsin-hydrochloric  acid. 

The  spermatozoa  of  the  Ehuste  salmon  show,  according  to 
Miescher,  a  great  resistance.  With  caustic-potash  and  soda  solu- 
tions they  give  a  cloudy,  gelatinous  mass  which  is  precipitated  as 
shreds  by  acids;  but  these  shreds  do  not  dissolve  in  an  excess  of  the 
-acid.  They  are  strongly  attacked  by  a  10-15^  solution  of  NaCl  or 
NaNO, ,  and  the  semen  is  converted  by  such  a  solution  into  a  stiff 
gelatin.  The  head  is  attacked,  but  not  the  tail  or  the  middle  part. 
This  last-mentioned  part,  like  the  tail,  contains  albumin,  which  is 
•dissolved  by  hydrochloric  acid  of  1  ]).  m.,  but  not  in  NaCl. 
Miescher  also  found  lecithin,  fat,  cholesterin,  guanin,  and  sarkiti 
in  relatively  large  amounts  in  the  salmon-semen.  The  organic 
constituent  occurring  in  the  largest  amount  in  the  salmon-semen 
is,  according  to  Meischer,  a  combination  of  nuclein  with  the  base 
protamin,  which  is  soluble  in  water  but  insoluble  in  alcohol  or 
ether.  According  to  Kossel,  the  nuclein  of  the  spermatozoa  is 
nucleic  acid  (see  Chapter  V),  and  a  combination  of  nucleic  acid  and 
protamin  is  supposed  to  exist  therein. 

FTOtamin.  This  base  is,  like  its  salts,  hardly  possible  to  obtain  in  perfectly 
characteristic  crystals.  The  platinum  double  salt  has  the  following  composi- 
tion, according  to  Piccard'^  :  PtCU  +  2(HCl.C»H,eN4503).  The  compounds 
with  hydrochloric  or  nitric  acid  dissolve  readily  in  water  and  with  difficulty 
in  alcohol.  They  are  insoluble  in  ether.  The  base  is  precipitated  by  silver 
nitrate,  potassium-mercuric  iodide,  potassium  ferricyanide,  and  phospho- 
molybdic  acid. 

'  Verb.  d.  naturf.  Qesellsch.  in  Basel,  Bd.  6;  also  Maly's  Jahresber.,  Bd.  4, 
S.  337. 

'  Maly's  Jahresber.,  Bd.  4,  S.  355. 


406  ORGANS  OF  GENERATION. 

According  to  Mieschek,  the  spermatozoa  of  salmon  contain 
487  p.  m.  nuclein,  268  p.  m.  protamin,  103  p.  m.  proteid  bodies, 
,75  p.  m.  lecithin,  22  p.  m.  cholesterin,  and  45  p.  m.  fat.  Piccaed 
found  60-80  p.  m.  guanin  and  sarkin  in  ripe  semen.  Kossel  and 
ScHiNDLER '  found  no  guanin,  but  xantMn  and  large  amounts  of 
adenin  and  hypoxanthin,  in  the  semen  of  the  carp. 

Inoko,^  who  investigated  the  semen  of  bulls,  boars,  and  salmon, 
found  the  four  ordinary  nuclein  bases  in  all.  The  xanthin  bases 
occurred  habitually  in  greater  quantity  than  the  sarkin  bases,  and 
the  relationship  between  the  two  was  very  variable. 

Sp  rmatin  is  a  name  whicb.  has  been  given  to  a  constituent  similar  to  alkali 
albuminate,  but  it  has  not  been  closely  studied. 

Prostatic  concrements  are  of  two  kinds.  One  is  very  small,  generally  oval 
iu  shape  with  concentric  layers.  In  young  but  not  in  older  persons  they  are 
colored  blue  by  iodine  (Iveksen).^  The  other  kind  is  larger,  sometimes  the 
size  of  the  head  of  a  pin,  and  consisting  chiefly  of  calcium  phosphate  (about 
700  p.  m.)  with  only  a  very  small  amount,  about  160  p.  m, ,  organic  substance.. 

(b)  Female  Generative  Organs. 

The  stroma  of  the  ovaries  are  of  little  interest  from  a  physio- 
logico-chemical  standpoint,  and  the  most  important  constituent  of 
the  ovaries,  the  Graaflfian /oZ?ic?es  with  the  ovum,  have  thus  far  not 
been  the  subject  of  a  careful  chemical  investigation.  The  fluid  in 
the  follicles  (of  the  cow)  do  not  contain,  as  has  been  stated,  the 
peculiar  bodies,  paralbumin  or  metalbumin,  which  are  found  in 
certain  pathological  ovarial  fluids,  but  seems  to  be  a  serous  liquid. 
The  corpora  lutea  are  colored  yellow  by  an  amorphous  pigment 
called  lutein.  Besides  this,  another  coloring-matter  sometimes 
occurs  which  is  not  soluble  in  alkali ;  it  is  crystalline,  but  not  iden- 
tical with  bilirubin  or  haematoidin ;  but  it  may  be  identified  as  a 
lutein  by  its  spectroscopic  behavior  (Piccolo  and  Lieben,  Kuhne. 
and  Ewald).' 

The  cysts  often  occurring  in  the  ovaries  are  of  special  patholog- 
ical interest,  and  these  may  have  essentially  different  contents,  de- 
pending upon  their  variety  and  origin. 

The  serous  cysts  (Hydrops  folliculorum  Graafii),  which 
are  formed  by  a  dilation  of  the  Graafian  follicles,  contain  a  serous 

'  Zeitschr.  f.  physiol.  Chem.,  Bd. 

2  Ihid. ,  Bd.  18. 

»L.  c. 

*  See  Chapter  VI,  p    145. 


SEIWUS  AND   PROLIFEROUS   CYSTS.  -iOT 

liquid  which  has  a  specific  gravity  of  1.005-1.022.  A  specific 
gravity  of  1.020  is  less  frequent.  Generally  the  specific  gravity  is 
lower,  1.005-1.014.  with  10-40  p.  m.  solids.  As  far  as  is  known, 
the  contents  of  these  cysts  do  not  essentially  differ  from  other  serous 
liquids. 

The  proliferous  cysts  (myxoid  cysts,  colloid  cysts),  w^hich 
are  developed  from  Pfluger's  epithelium-tubes,  may  have  a  con- 
tents of  a  very  variable  composition. 

We  sometimes  find  in  small  cysts  a  semi-solid,  transparent,  or 
somewhat  cloudy  or  opalescent  mass  which  appears  like  solidified 
glue  or  quivering  jelly,  and  which  has  been  called  co/Zojc?  because  of 
its  physical  properties.  In  other  cases  the  cysts  contain  a  thick, 
tough  mass  which  can  be  drawn  out  into  long  threads,  and  as  this 
mass  in  the  different  cysts  is  more  or  less  diluted  with  serous  liquids 
their  contents  may  have  a  variable  consistency.  In  other  cases  the 
small  cysts  may  also  contain  a  thin,  watery  fluid.  The  color  of  the 
contents  is  also  variable.  In  certain  cases  they  are  bluish  white, 
opalescent,  and  in  others  yellow,  yellowish  brown,  or  yellowish  with 
a  sliade  of  green.  They  are  often  colored  more  or  less  chocolate- 
brown  or  red-brown,  due  to  the  decomposed  blood-coloring  matters. 
The  reaction  is  alkaline  or  nearly  neutral.  The  specific  gravity, 
which  may  vary  considerably,  is  generally  1.015-1.030,  but  may  in 
few  cases  be  1.005-1.010  or  1.050-1.055.  The  amount  of  solids  is 
very  variable.  In  rare  cases  they  amount  to  only  10-20  p.  m. ; 
ordinarily  they  vary  between  50-70-100  p.  m.  In  a  few  cases 
150-200  p.  m.  solids  have  been  found. 

As  form-elements  we  find  red  and  white  blood-corpuscles,  gran- 
ular cells,  partly  fat-degenerated  epithelium  and  partly  large  so- 
called  Gluge's  corpuscles,  fine  granular  masses,  epithelium-cells, 
cliolesterin  crystals,  and  colloid  corpuscles — large,  circular,  highly 
refractive  formations. 

Though  the  contents  of  the  proliferous  cyst  may  have  a  variable 
composition,  still  it  may  be  characterized  in  typical  cases  by  its 
slimy  or  ropy  consistency;  by  its  grayish-yellow,  chocolate-brown, 
sometimes  whitish-gray  color;  and  by  its  relatively  high  specific 
gravity,  1.015-1.025.  Such  a  liquid  does  not  ordinarily  show  a 
spontaneous  fibrin-coagulation. 

We  consider  colloid,  metalhumin,  and  paralbumin  as  character- 
istic constituents  of  these  cysts. 

Colloid.     This  name  does  not  designate  any  particular  chemical 


408  ORGANS  OF  GENERATION. 

substance,  but  is  given  to  the  contents  of  tumors  with  certain  phys- 
ical properties  similar  to  gelatin  jelly.  Colloid  is  found  as  a  diseased 
product  in  several  organs. 

Colloid  is  a  gelatinous  mass,  insoluble  in  water  and  acetic  acid; 
it  is  dissolved  by  alkalies  and  gives  a  liquid  which  is  not  precipitated 
lay  acetic  acid  or  by  acetic  acid  and  potassium  ferrocyanide.  Ac- 
cording to  Pfannenstiel  '  such  a  colloid  is  designated  yS-pseu- 
•domucin. 

Sometimes  a  colloid  is  found  which,  when  treated  with  a  very 
dilute  alkali,  gives  a  solution  similar  to  a  mucin  solution.  On 
"boiling  with  acids  colloid  gives  a  reducing  substance.  It  is  related 
to  mucin,  and  it  is  considered  by  certain  investigators  as  a  trans- 
formed mucin.  A  colloid  found  by  Wuktz  '•'  in  the  lungs  contains 
C  48.09,  H  7.47,  N  7.00,  and  0  37.44  </o.  Colloids  of  different  origin 
seem  to  have  an  unequal  composition. 

Metalbumin.  This  name  Scherer'  gave  to  a  protein  substance 
found  by  him  in  an  ovarial  fluid.  The  metalbumin  was  considered 
by  ScHERER  to  be  an  albuminous  body,  but  it  belongs  to  the  mucin 
group,  and  it  is  for  this  reason  calledi  pseudomucin  by  the  author." 

Pseudomucin.  This  body,  which,  like  mucin,  gives  a  reducing 
substance  when  boiled  with  acids,  is  a  mucoid  of  the  following 
composition:  C 49.75,  H  6.98,  N  10.28,  S  1.25,  0  31.74^  (author). 
With  water  pseudomucin  gives  a  slimy,  ropy  solution,  and  it  is  this 
substance  which  gives  the  fluid  contents  of  the  ovarial  cysts  their 
typical  ropy  property.  Its  solutions  do  not  coagulate  on  boiling, 
but  only  become  milky-opalescent.  Unlike  mucin  solutions,  pseu- 
domucin solutions  are  not  precipitated  by  acetic  acid.  With  alcohol 
they  give  a  coarse  flocculent  or  thready  precipitate  which  is  soluble 
even  after  having  been  kept  under  water  or  alcohol  for  a  long  time. 
MiTJUKOFF '  has  isolated  and  investigated  a  colloid  from  an  ovarial 
cyst.  It  had  the  following  composition:  C  51.76,  H  7.76,  N.  10.7, 
S  1.09,  and  0  28.69  fo,  and  differed  from  mucin  and  pseudomucin 


1  Arch.  f.  Gynak.,  Bd.  38. 

*  See  Lebert,  Beitr.  zur  Kenntnniss  des  Gallertkrebses,  Vircbow's  Arch., 
Bd.  4. 

•Verb.  d.  pbysik.-med.  Gesellscb.  in  Wiirzburg,  Bd.  2,  and  Sitzungsber. 
der  pbysik.-med.  Gesellscb.  in  Wiirzburg  filr  1864-1865;  Wiirzburg  med. 
Zeitscbr.,  Bd.  7. 

•»  Zeitscbr.  f.  pbysiol.  Cbem.,  Bd.  6. 

'  Ueber  das  paramucin.    Inaug.-Diss.,  Berlin,  1895. 


PSEUDOMUCm.  409 

by  reducing  Fehling's  solution  before  boiling  with  ucid.     He  calls 
it  paramncin. 

Paralbumin  is  another  substance  discovered  by  Scherer,'  and 
which  occurs  in  ovarial  liquids  and  also  in  ascites  fluids  with  the 
simultaneous  presence  of  ovarial  cysts  and  rupture  of  the  same.  It 
is  therefore  only  a  mixture  of  pseudomucin  with  variable  amounts 
of  proteid,  and  the  reactions  of  paralbumin  are  correspondingly 
variable. 

The  detection  of  metalbumin  and  paralbumin  is  naturally  con- 
nected with  the  detection  of  pseudomucin.  A  typical  ovarial  fluid 
containing  pseudomucin  is,  as  a  rule,  sufiicientlj  characterized  by 
its  physical  properties,  and  a  special  chemical  investigation  is  only 
necessary  in  cases  where  a  serous  fluid  contains  very  small  amounts 
of  pseudomucin.  We  proceed  in  the  following  way:  The  proteid 
is  removed  by  heating  to  boiling  with  the  addition  of  acetic  acid; 
the  filtrate  is  strongly  concentrated  and  precipitated  by  alcohol. 
The  precipitate  is  carefully  washed  with  alcohol,  and  then  dissolved 
in  water.  A  part  of  this  solution  is  digested  with  saliva  at  the 
temperature  of  the  body  and  then  tested  for  glucose  (derived  from 
glycogen  or  dextrin).  If  glycogen  is  present,  it  will  be  converted 
into  glucose  by  the  saliva;  precipitate  again  with  alcohol  and  then 
proceed  as  in  the  absence  of  glycogen.  lu  this  last-mentioned 
case,  first  add  acetic  acid  to  the  solution  of  the  alcohol  precipitate 
in  water  so  as  to  precipitate  any  existing  mucin.  The  precipitate 
produced  is  filtered,  the  filtrate  treated  with  '^'fo  HCl,  and  wanjied 
on  the  water-bath  until  the  liquid  is  deep  brown  in  color.  In  the 
presence  of  pseudomucin  this  solution  gives  Trommer's  test. 

The  other  protein  bodies  which  have  been  found  in  cystic  fluids 
are  serglohulin  and  seralbumin,  peptone  (?),  mucin,  and  mucin- 
peptone  (?).  Fibrin  only  occurs  in  exceptional  cases.  The  quantity 
of  mineral  bodies  on  an  average  amounts  to  about  10  p.  m.  The 
amount  of  extractive  bodies  {cholesterin  and  icrea)  and  fat  is  ordi- 
narily 2-4:  p.  m.  The  remaining  solids,  which  constitute  the  chief 
mass,  are  albuminous  bodies  and  pseudomucin. 

The  intraligamentary,  papillary  cysts  contain  a  yellow, 
yellowish-green,  or  brownish-green  liquid  which  contains  either  no 
pseudo-mucin  or  very  little.  The  specific  gravity  is  generally  rather 
high,  1.032-1.036,  with  90-100  p.  m.  solids.  The  principal  con- 
stituents are  the  albuminous  bodies  of  blood-serum. 

The  rare  tubo-ovarial  cysts  contain  as  a  rule  a  watery,  serous 
fluid  containing  no  pseudomucin. 

'  L.  c. 


410  ORGANS  OF  GENERATION. 

The  parovarial  cysts  or  the  cysts  of  the  ligamenta  lata  may 
attain  a  considerable  size.  In  general,  and  when  quite  typical,  the 
contents  are  watery,  mostly  very  pale  yellow-colored,  water-clear  or 
only  slightly  opalescent  liquids.  The  specific  gravity  is  low,  1.002- 
1.009;  and  the  solids  only  amount  to  10-20  p.  m.  Pseudomucin 
does  not  occur  as  a  typical  constituent;  proteid  is  sometimes 
absent,  and  when  it  does  occur  the  quantity  is  very  small.  The 
principal  part  of  the  solids  consists  of  salts  and  extractive  bodies. 
In  exceptional  cases  the  fluid  may  be  rich  in  proteid  and  may 
show  a  higher  specific  gravity. 

In  regard  to  the  quantitative  composition  of  the  fluid  from 
ovarial  cysts  we  refer  the  reader  to  the  work  of  Oeeum.' 

The  Eg^. 

The  small  ova  of  man  and  mammals  cannot,  for  evident  reasons, 
be  the  subject  of  a  searching  chemical  investigation.  Up  to  the 
present  time  the  eggs  of  birds,  amphibians,  and  fishes  have  been 
investigated,  but  above  all  the  hen's  Qgg.  We  will  here  occupy 
ourselves  with  the  constituents  of  this  last. 

The  yolk  of  the  hen's  egg.  In  the  so-called  white  yolk,  which 
forms  the  germ  with  a  process  reaching  to  the  centre  of  the  yolk 
(latebrd),  and  also  a  layer  found  between  the  yolk  and  yolk-mem- 
brane, we  find  proteid,  nuclein,  lecithin,  and  potassium  (Lieber- 
MAN]sr)\  The  occurrence  of  glycogen  is  doubtful.  The  yolk- 
membrane  consists  of  an  albumoid  similar  in  certain  respects  to 
keratin  (Liebermann). 

The  principal  part  of  the  yolk — the  nutritive  yolk  or  yellow — is 
a  viscous,  non-transparent,  pale-yellow  or  orange-yellow  alkaline 
emulsion  of  a  mild  taste.  The  yolk  contains  vitelliti,  lecithin, 
cholesterin,  fat,  coloring  matters,  traces  of  neuridin  (Brieger),^ 
glucose  in  very  small  quantities,  and  mineral  bodies.  The  occur- 
rence of  cerebrin  and  of  granules  similar  to  starch  CDareste)  *  has 
not  been  positively  proved. 

Ovovitellin.  This  body  is  generally  considered  as  a  globulin, 
but  it  resembles  a  nucleoalbumin  more.     The  question  as  to  what 

'  Kemiske  Studier  over  Ovariecystevoedsker,   etc.  Koebenhavn,  1884.     See 
also  Maly's  Jahresber.,  Bd.  14,  S,  459. 
«  Pfliiger's  Arch.,  Bd.  43. 
*  Ueber  Ptomaine.     Berlin,  1885. 
■*  Compt.  rend.,  Tome  72. 


0  T  ^0  VITELLIN.  411 

relationship  other  protein  substances  which,  like  the  aleuron-grains 
of  certain  seeds  and  the  so-called  "  dotterpldttchen  "  of  the  eggs  of 
certain  fishes  and  amphibians,  are  related  to  ovovitellin,  bear  to  this 
substance,  is  a  question  which  requires  further  investigation. 

The  ovovitellin  which  has  been  prepared  from  the  yolk  of  eggs 
is  not  a  pure  albuminous  body,  but  always  contains  lecithin. 
Hoppe-Seyler  found  25^  lecithin  in  vitellin  and  also  some  pseudo- 
nuclein.  The  lecithin  may  be  removed  by  boiling  alcohol,  but  the 
vitellin  is  changed  thereby,  and  it  is  therefore  probable  that  the  leci- 
thin is  chemically  united  with  the  vitellin  (Hoppe-Seyler).' 
BuNGE "  prepared  a  pseudonuclein  by  digesting  the  yolk  with  gas- 
tric juice,  and  this  pseudonuclein,  according  to  him,  is  of  great 
importance  in  the  formation  of  the  blood,  and  on  these  grounds  he 
called  it  h(2matogen.  This  heematogen — whose  composition  is  as 
follows:  C  42.11,  H  6.08,  N  14.73,  S  0.55,  P  5.19,  Fe  0,29,  and 
0  31.05^ — seems  to  be  a  decomposition  product  of  vitellin. 

Vitellin  is  similar  to  the  globulins  in  that  it  is  insoluble  in 
water,  but  on  the  contrary  soluble  in  dilute  neutral-salt  solutions 
(although  the  solution  is  not  quite  transparent).  It  is  also  soluble 
in  hydrochloric  acid  of  1  p.  m.  and  in  very  dilute  solutions  of  alka- 
lies or  alkali  carbonates.  It  is  precipitated  from  its  salt  solution 
by  diluting  with  water,  and  when  allowed  to  stand  some  time  in 
contact  with  water  the  vitellin  is  gradually  changed,  forming  a  sub- 
stance more  like  the  albuminates.  The  coagulation  temperature 
for  the  solution  containing  salt  (NaCl)  lies  between  -f-  70°  and  75°  C. 
or,  when  heated  very  rapidly,  at  about  +  80°  C.  Vitellin  differs 
from  the  globulins  in  yielding  pseudonuclein  by  pepsin  digestion. 
It  is  not  always  or  only  in  part  precipitated  by  NaCl  in  substance. 

The  chief  points  in  the  preparation  of  ovovitellin  are  as  follows: 
The  yolk  is  thoroughly  agitated  with  ether;  the  residue  is  dissolved 
in  a  10,^  common-salt  solution,  filtered,  and  the  vitellin  precipitated 
by  adding  an  abundance  of  water.  The  vitellin  is  now  purified  by 
repeatedly  redissolving  in  dilute  common-salt  solutions  and  pre- 
cipitating by  water. 

Ichthalin,  which  occurs  in  the  eggs  of  the  carp  and  other  fishes,  is,  according 
to  KossEL  and  Walter,  *  an  amorphous  modification  of  the  crystalline  body 
ichthidin,  which  occurs  in  the  eggs  of  the  carp.  Ichthulin  is  precipitated  on 
diluting  with  water.  It  used  to  be  considered  as  a  vitellin.  According  to 
Walter  it  yields  a  pseudonuclein  on  peptic  digestion,  and  this  pseudonuclein 

•  Med.  chem.  Untersuch.,  S.  216. 
'  Zeitschr.  f.  physiol.   Chem.,  Bd.  9. 
» Ibid. ,  Bd.  15. 


412  ORGANS  OF  GENEBATION. 

ffives  a  reducing  carboliydrate  on  boiling  witli  sulphuric  acid.  Iclitliulin  has 
the  following  composition  :  C  53.43  ;  H  7.63  ;  N  15.63  ;  0  22.19;  S  0.41  ; 
P  0.43.     It  also  contains  iron. 

The  yolk  also  contains,  besides  vitellin,  alkali-alhuminate  and 
alMimin. 

The  fat  of  the  yolk  of  the  egg  is,  according  to  Liebermann"/  a 
mixture  of  a  solid  and  a  liquid  fat.  The  solid  fat  consists  chiefly  of 
tripalmitin  with  some  stearin.  On  the  saponification  of  the  egg-oil 
LiEBERMANK  obtained  40^  oleic  acid,  38.04^  palmitic  acid,  and 
15.21^  stearic  acid.  The  fat  of  the  yolk  of  the  Qgg  contains  less 
carbon  than  other  fats,  which  may  depend  on  the  presence  of  mono- 
and  diglycerides  or  on  a  quantity  of  fatty  acid  deficient  in  carbon 
(Liebermann). 

Lutein.  Yellow  or  orange-red  amorphous  coloring  matters 
occur  in  the  yellow  of  the  egg  and  in  several  other  places  in  the 
animal  organism ;  for  instance,  in  the  blood-serum  and  serous  fluids, 
fatty  tissues,  milk-fat,  corpora  lutea,  and  in  the  fat-globules  of  the 
retina.  These  coloring  matters,  which  also  occur  in  the  vegetable 
kingdom  (Thudichum'),  have  been  called  luteines  or  lipochromes. 

The  luteines,  which  among  themselves  show  somewhat  different 

properties,  are  all  soluble  in  alcohol,  ether,  and  chloroform.     They 

differ    from    the    bile-pigment,    bilirubin,    in   that   they   are   not 

separated  from  their  solution  in  chloroform  by  water  containing 

alkali,  and  also  in  that  they  do  not  give  the  characteristic  play  of 

colors  with  nitric  acid  containing  a  little  nitrous  acid,  but  give  a 

transient  blue  color,  and  lastly  they  give  an  absorption-spectrum  of 

ordinarily  two  bands,  of  which  one  covers  the  line  F  and  the  other 

lies  between  the  lines  F  and  G.     The  luteines  withstand  the  action 

of  alkalies  so  that  they  are  not  changed  when  we  remove  the  fats 

present  by  means  of  saponification. 

Lutein  has  not  been  prepared  pure.  Maly'  has  found  two  pigments  free 
from  iron  in  the  eggs  of  a  water-spider  {maja  squinado),  one  a  red,  mtelloru- 
Mn,  and  the  other  a  yellow  pigment,  mtellolutein.  Both  of  these  pigments  are 
colored  blue  by  nitric  acid  containing  nitrous  acid,  and  beautifully  green  by 
concentrated  sulphuric  acid.  The  absorption-bands,  especially  of  the  vitello- 
lutein,  correspond  very  nearly  with  those  of  ovolutein. 

The  mineral  todies  of  the  yolk  of  the  egg  consist,  according  to 
POLECK,-  of  51.2-65,7  parts  soda,  89.3-80.5  potash,  122.1-132.8 

•  L.  c. 

»  Centralbl.  f.  d.  med.  Wissensch.,  1869,  No.  1. 
»  Monatshefte  f.  Chem.,  Bd.   2. 

*  Cited  from  QorupBesanez,  Lehrbuch  d.  physiol.  Chem.,  4.  Aufl.,  S. 
740. 


WHITE  OF  THE  EGG.  4l;J 

lime,  20.7-21.1  magnesia,  14.5-11.90  iron  oxide,  638.1-667.0 
phosphoric  acid,  and  5.5-14.0  parts  silicic  acid  in  1000  parts  of  tlie 
ash.  We  find  phosphoric  acid  and  lime  the  most  abundant,  and 
then  potash,  which  is  somewhat  greater  in  quantity  than  the  soda. 
These  results  are  not,  however,  quite  correct,  first,  because  no 
dissolved  phosphate  occurs  in  the  yolk  (Liebermann),  and  secondly, 
in  burning,  phosphoric  and  sulphuric  acids  are  produced  and  these 
drive  away  the  chlorine,  which  is  not  accounted  for  in  the  preceding 
analyses. 

The  yolk  of  the  hen's  egg  weighs  about  12-18  grms.  The 
quantity  of  water  and  solids  amounts,  according  to  Parkes,"  to 
471.9  p.  m.  and  528,1  p.  m.  respectively.  Among  the  solids  he 
found  156.3  p.  m.  proteid,  3.53  p.  m.  soluble  and  6.12  p.m.  in- 
soluble salts.  The  quantity  of  fat,  according  to  Parkes,  is  228.4 
p.  m.,  the  lecithin,  calculated  from  the  amount  of  jihosphorus  in 
the  organic  substance  in  the  alcohol-ether  extract,  was  107.2  p.  m., 
and  the  cholesterin  17.5  p.m. 

The  white  of  the  egg  is  a  faint-yellowish  albuminous  fluid  en- 
closed in  a  framework  of  thin  membranes;  and  this  fluid  is  in  itself 
very  liquid,  but  seems  viscous  because  of  the  presence  of  these  fine 
membranes.  That  substance  which  forms  the  membranes,  and  of 
which  the  chalaza  consists,  seems  to  be  a  body  nearly  related  to 
horn  substances  (Liebermann'). 

The  white  of  the  Qgg  has  a  specific  gravity  of  1.045  and  always 
has  an  alkaline  reaction.  It  contains  850-880  p.  m.  water,  100-130 
p.  m.  proteid  bodies,  and  7  p.  m.  salts.  Among  the  extractive 
bodies  Lehmann  found  a  fermentable  variety  of  sugar  which 
amounted  to  5  p.  m.  or,  according  to  Meissner,  80  p.  m.  of  the 
solids.'  Besides  these,  we  find  in  the  white  of  the  Qgg  traces  of  fats, 
soaps,  lecithin,  and  cholesterin. 

The  white  of  the  egg  during  incubation  becomes  transparent  on  boiling  and 
acts  in  many  respects  like  alkali-albuminate.  This  albumin  Takchanobp* 
called  "  tatalbumin." 

The  albuminous  bodies  of  the  white  of  the  egg  belong  partly  to 
the  globulin  and  partly  to  the  albumin  group.  Besides  these,  the 
white  of  the  egg  contains  a  mucoid  substance. 

'  Hoppe-Seyler,  Med.  chem.  Untersuch. ,  Heft  2,  S.  209 
»L.  c. 

*  Cited  from  Gorup-Besanez,  Lehrbuch,  4.  Aufl.,  S.  739. 

*  Pfltiger's  Arch.,  Bdd.  31,  33,  and  39. 


414  OEGAJ^S  OF  GENERATION. 

The  ovgldbidin  is,  according  to  Dillner,'  closely  related  to 
serglobulin.  On  diluting  the  white  of  the  Q.g^  with  water  it  partly 
separates.  It  is  also  precipitated  by  magnesium  sulphate.  The 
quantity  of  globulins  in  the  white  of  the  ^gg  is  on  an  average  6.67 
p.  m.,  or  about  67  p.  m.  of  the  total  proteids.  According  to  Coein 
and  Berard/  we  have  two  globulins  in  the  white  of  the  Qgg,  one 
coagulating  at  +  57.5°  C,  and  the  other  at  +  67°  0. 

Ovalbumin,  or  the  albumin  of  the  white  of  the  Qgg.  Ovalbumin 
was  first  obtained  in  a  crystalline  form  by  Hofmeister^  by  allow- 
ing its  solution  in  a  half -saturated  ammonium-sulphate  solution  to 
evaporate  very  slowly.  This  crystalline  ovalbumin  is  later  further 
studied  by  G-abriel/  Bokdztnski  and  Zoja/  and  the  two  last- 
mentioned  investigators  were  able,  by  fractional  crystallization,  to 
show  that  ovalbumin  was  probably  a  mixture  of  several  albumins  of 
about  the  same  elementary  composition  but  with  somewhat  differ- 
ent coagulation-temperature,  solubility,  and  specific  rotation.  In 
the  main  these  results  are  in  accord  with  the  views  of  many  other 
investigators,  such  as  Gautier,'  Bechamp,'  Corin"  and  Berard,' 
on  the  occurrence  of  several  albumins,  but  in  details  they  do  not 
agree  very  well.  According  to  Gautier  and  Bechamp  ovalbumin 
is  a  mixture  of  two  albumins  with  the  coagulation-temperature  of 
60-63°  and  71-74°  0.  respectively,  while  according  to  Corik  and 
Berard  it  is  a  mixture  of  three  albumins  with  the  coagulation- 
temperature  of  67,  72,  and  82°  C,  respectively.  According  to 
BoKDZYNSKi  and  Zoja  the  portion  which  dissolves  with  difficulty 
coagulates  at  64.5°,  while  the  readily  soluble  portion  coagulates  at 
55.5-56°  C.  The  elementary  composition  of  ovalbumin  has  not 
been  positively  established.  Bondzynski  and  Zoja  found  0  52.07- 
52.44,  H  6.95-7.26,  N.  15.11-15.58,  and  S  1.61-1.70^  for  four 
different  fractions,  which  agree  well  with  the  results  of  the  author, 
namely,  C  52.25,  H  6.90,  N  15.25,  S  1.67-1.93^.      noFMEiSTBR,' 

'  Upsala  Lakarefs.  Forh.,  Bd.  30;  also  Maly's  Jaliresber. ,  Bd.  15,  S.  31. 
2  Travaux  du  laboratoire   de  FUniversite   de  LiSge,    Tome  2;  also  Maly's 
Jabresber.,  Bd.  18,  S.  13. 

^  Zeitscbr.  f.  pbysiol.  Chem.,  Bdd.  14  and  16. 

'^  Ihid.,  Bd.  15. 

5  Ihid.,  Bd.  19. 

*  Bull,  de  la  soc.  cbim.,  Tome  14. 

1  lUd.,  Tome  21. 

8  L.  c. 

9  Zeitscbr.  f.  pbysiol.  Cbem.,  Bd,  16. 


OVALBUMIN  AND   OVOMUCOID.  415 

on  the  contrary,  found  higher  figures,  53.28,'^,  for  tlie  carbon  uud 
lower,  15.0  and  1.09^,  for  tlie  nitrogen  and  sulphur  respectively. 
The  specific  rotation  was  determined  by  Starke  '  as  a  (D)=  —  38°. 
BoNDZYNSKi  and  Zoja  found  25.8-26.2°.  29.16°,  34.18°,  and 
42.54°  for  various  fractions.  Ovalbumin  has  the  properties  of  the 
albumins  in  general,  but  differs  from  seralbumin  in  the  following : 
Its  specific  rotation  is  lower.  It  is  quickly  rendered  insoluble  by 
alcohol.  It  is  precij)itated  by  a  suflficient  quantity  of  hydrochloric 
acid,  but  dissolves  with  greater  difficulty  than  seralbumin  in  an 
excess  of  the  acid.  Ovalbumin  in  solution,  when  introduced  into 
the  blood-circulation,  passes  into  the  urine,  which  is  not  the  case 
with  seralbumin. 

Ovalbumin,  or,  more  correctly,  the  mixture  of  albumins,  may 
be  obtained,  according  to  Starke,  by  precipitating  the  globulins 
by  MgSO,  at  20°  C.  and  saturating  the  filtrate  with  Na^SO^  at  the 
same  temperature.  The  ovalbumin  which  separates  is  filtered, 
pressed,  dissolved  in  water,  and  freed  from  salts  by  dialysis.  The 
dialyzed  solution  is  then  evaporated  in  a  vacuum  or  at  40°-50°  C. 
If  precipitated  with  alcohol,  albumin  becomes  quickly  insoluble. 

To  prepare  crystallized  ovalbumin  mix  the  white  of  e^i'g, 
previously  beaten  and  separated  from  the  foam,  with  an  equal  vol- 
ume of  a  saturated  solution  of  ammonium  sulphate,  filter  off  the 
globulin,  and  allow  the  filtrate  to  evaporate  slowly  in  not  too  thin 
layers  at  the  temperature  of  the  room.  The  mass,  which  separates 
after  a  time,  is  dissolved  in  water,  treated  with  ammonium  sulphate 
solution  until  a  cloudiness  commences,  and  then  allowed  to  stand. 
After  repeated  recrystallizations  the  mass  is  treated  either  with 
alcohol,  which  makes  the  crystals  insoluble,  or  they  are  dissolved  in 
water  and  purified  by  dialysis.  The  albumin  does  not  crystallize 
from  this  solution  on  spontaneous  evaporation. 

Ovomucoid.  This  substance,  first  observed  by  Neumeister' 
and  considered  by  him  as  pseudo-peptone  and  then  later  studied  by 
Salkowski,"  is,  according  to  0.  Th.  Morner,'  a  mucoid  with 
12.65^  nitrogen  and  2.20^  sulphur.  On  boiling  with  dilute  min- 
eral acids  it  yields  a  reducing  substance.  Ovomucoid  exists  to  a 
great  extent  in  hens'  eggs,  the  solids  of  which,  in  round  numbers, 
contain  10^. 

A  solution  of  ovomucoid  is  not  precipitated  by  mineral  acids 

•  Upsala  Lakarefs  F5rh.,  Bd.  16;  also  Maly's  Jaliresber.,  Bd.  11,  S.  17. 

*  Zur  Physiologic  der  Eiweissresorption,  etc.  Zeitschr.  f.  Biologie.,  Bd., 
27. 

3  Centrabl.  f.  d.  med.  Wissensch.  1893. 
'  Zeitsclir.  f.  physiol.  Chem.  Bd.  18. 


416  ORGANS  OF  OENERATION. 

nor  by  organic  acids,  with  the  exception  of  phosphotungstic  acid 
and  tannic  acid.  It  is  not  precipitated  by  metallic  salts,  but  basic 
lead  acetate  and  ammonia  give  a  precipitate.  Ovomucoid  is  pre- 
cipitated by  alcohol,  but  sodium  chloride,  sodium  sulphate,  and 
magnesium  sulphate  give  no  precipitates  either  at  the  ordinary 
temperature  nor  when  added  to  saturation  at  30°  C.  Its  solutions 
are  not  precipitated  by  an  equal  volume  of  a  saturated  solution  of 
ammonium  sulphate,  but  are  precipitated  on  adding  more  salt 
thereto.  The  substance  is  not  precipitated  on  boiling,  but  the 
part  which  has  become  insoluble  in  cold  water  and  then  dried  is 
precipitated  when  dissolved  in  boiling  water. 

Ovomucoid  may  be  prepared  by  removing  all  the  proteids  by 
boiling  with  the  addition  of  acetic  acid,  and  then  concentrating 
the  filtrate  and  precipitating  with  alcohol.  The  substance  is  puri- 
fied by  repeated  solution  in  water  and  precipitating  with  alcohol. 

The  mineral  bodies  of  the  white  of  the  Qgg  have  been  analyzed 
by  PoLECK  and  Weber.  '  They  found  in  1000  parts  of  the  ash : 
276.6-284.5  grms.  potash,  235.6-329.3  soda,  17.4-29  lime,  16-31.7 
magnesia,  4.4-5.5  iron  oxide,  238.4-285.6  chlorine,  31.6-48.3 
phosphoric  acid  (P^OJ,  13.2-26.3  sulphuric  acid,  2.8-20.4  silicic 
acid,  and  96.7-116  grms.  carbon  dioxide.  Traces  of  fluorine  have 
also  been  found  (Nickles").  The  ash  of  the  white  of  the  egg  con- 
tains, as  compared  with  the  yolk,  a  greater  amount  of  chlorine  and 
alkalies,  and  a  smaller  amount  of  lime,  phosphoric  acid,  and  iron. 

The  Shell-membrane  and  the  Egg-shell.  The  shell-membrane 
consists,  as  above  stated  (page  49),  of  a  keratin  substance.  The 
shell  contains  very  little  organic  substance,  36-65  p.  m.  The  chief 
mass,  more  than  900  p.  m.,  consists  of  calcium  carbonate;  besides 
this  there  are  very  small  amounts  of  magnesium  carbonate  and 
earthy  phosphates. 

The  different  coloring  of  birds'  eggs  depends  upon  several  different  coloring 
matters.  Among  these  we  find  a  red  or  reddish-brown  pigment  called  "  ooro- 
dein"  ^yj  Sokby,^  which  is  perhaps  identical  with  hsematoporphyrin.  The 
green  or  blue  coloring  matter,  Sorby's  oocyan,  seems,  according  to  Lieber- 
mann/ and  Krukenberg,^  to  be  -p&riXj  hiliverdin  and  partly  a  blue  (Zm«a- 
tive  of  the  bile -pigments. 

»  Cited  from  Hoppe  Seyler's  Physiol.  Chem.,  S.  778. 
^  Comp.  rend.,  Tome  43. 

2  Cited  from  Krukenberg,  Verb.  d.  phys.-chem.  Gesellsch.  in  Wiirzburg, 
Bd.  17. 

^  Ber.  d.  deutsch.  chem.  Ge.sellsch.,  Bd,  11. 
5  L.  c. 


SHELL   MEMBRANE  AND   THE  EGG-SHELL.  417 

The  eggs  of  birds  have  a  space  at  tlieir  blunt  end  filled  with 
gas;  this  gas  contains  on  an  average  18.9-19.9  per  cent  oxygen 
(Hufner).  ' 

The  weight  of  a  hen^s  egg  varies  between  40-60  grammes  and 
may  weigh  sometimes  70  grms.  The  shell  and  shell-membrane 
together,  when  carefully  cleaned,  but  still  in  the  moist  state,  weigh 
5-8  grms.  The  yolk  weighs  12-18  and  the  white  23-34,  or  about 
double. 

The  white  of  the  egg  of  cartilaginous  and  bony  fishes  contains  only  traces 
of  true  albumin,  and  the  cover  of  the  frog's  egg  consists,  according  to  Giacosa,' 
of  mucin.  The  crystalline  formations  (yolk-spherules  or  dotterpldttrJien)  which 
have  been  observed  in  the  egg  of  the  tortoise,  frog,  ray,  shark,  and  other 
fishes,  and  which  are  described  by  Valenciennes  and  Fremy^  under  the 
names  emydin,  ichtldn,  icMhidin,  and  irhthulin,  seem,  as  above  stated  in  con- 
nection with  ichthulin,  to  consist  chiefly  of  phosphoglycoproteids.  The  egg 
of  the  river-crab  and  the  lobster  contain  the  same  pigment  as  the  shell  of 
the  animal.  This  pigment,  called  cyanocrystallin,  becomse  red  on  1  oiling  in 
water. 

In  fos  il  eggs  (of  aptenodytes,  pelecanus,  and  iiall.eus)  in  old  guano 
deposits  a  yellowish-white,  silky,  laminated  combination  has  been  found  which 
is  called  gaanovulit,  (NH4)3S04  +  2KjS04  +  3KHSO4  +  4HaO,  and  which  is 
easily  soluble  in  water,  but  is  insoluble  in  alcohol  and  ether. 

Those  eggs  which  develop  outside  of  the  mother-organism  must 
contain  all  the  elements  necessary  for  the  young  animals.  One 
finds,  therefore,  in  the  yolk  and  white  of  the  egg  an  abundant 
quantity  of  albuminous  bodies  of  different  kinds,  and  especially  a 
phosphorized  proteid  in  the  yolk.  Further,  we  also  find  lecithin 
in  the  yolk,  which  seems  habitually  to  occur  in  the  developing  cell. 
The  occurrence  of  glycogen  is  doubtful,  and  the  carbohydrates  are 
perhaps  represented  by  a  very  small  amount  of  glucose  and  ovomu- 
coids. On  the  contrary,  the  egg  contains  a  large  proportion  of 
fat,  which  doubtless  is  an  important  source  of  nutrition  and  res- 
piration for  the  embryo.  The  cholesterin  and  the  lutein  can  hardly 
have  a  direct  influence  on  the  development  of  the  embryo.  The 
egg  also  seems  to  contain  the  mineral  bodies  necessary  for  the 
development  of  the  young  animal.  The  lack  of  phosphoric  acid  is 
compensated  by  an  abundant  amount  of  phosphorized  organic  sub- 
stance, and  the  nucleoalbumin  containing  iron,  from  which  the 
hgematogen  (see  page  411)  is  formed,  is  doubtless,  as  Bunge  claims^ 
of  great  importance  in  the  formation  of  the  hgemoglobin  containing; 

'  Du  Bois-Reymond's  Arch.,  1893. 

«  Zeitschr.    f.  physiol.  Chem.,  Bd.  7. 

'  Cited  from  Hoppe-Seyler's  Physiol,  Chem.,  S.  77. 


418  ORGANS    OF  GENERATION. 

iron.  The  silicic  acid  necessary  for  tlie  development  of  the  feath- 
ers is  also  found  in  the  egg. 

During  the  period  of  incubation  the  Qgg  loses  weight,  chiefly 
due  to  loss  of  water.  The  quantity  of  solids,  especially  the  fat  and 
the  proteids,  diminishes  and  the  egg  gives  off  not  only  carbon 
dioxide,  but  also,  as  Liebermann  '  has  shown,  nitrogen  or  a  nitrog- 
enous substance.  The  loss  is  compensated  by  the  absorption  of 
oxygen,  and  it  is  found  that  during  incubation  a  respiratory 
exchange  of  gas  takes  place.  While  the  quantity  of  dry  substance 
in  the  egg  during  this  period  always  decreases,  the  quantity  of 
mineral  bodies,  proteid,  and  fat  always  increases  in  the  embryo. 
The  increase  in  the  amount  of  fat  in  the  embryo  depends,  accord- 
ing to  LiEBERMANN,  in  great  part  upon  a  taking  up  of  the  nutri- 
tive yolk  in  the  abdominal  cavity.  The  weight  of  the  shell  and  the 
quantity  of  lime-salts  contained  therein  remains  unchanged  during 
incubation.  The  yolk  and  white  together  contain  the  necessary 
quantity  of  lime  for  development. 

The  most  complete  and  careful  chemical  investigation  on  the 
development  of  the  embryo  of  the  hen  has  been  made  by  Lieber- 
MANN.  From  his  researches  we  may  quote  the  following :  In  the 
earlier  stages  of  the  development,  tissues  very  rich  in  water  are 
formed,  but  on  the  continuation  of  the  development  the  quantity 
of  water  decreases.  The  absolute  quantity  of  bodies  soluble  in  water 
increases  with  the  development,  while  their  relative  quantities,  as 
compared  to  the  other  solids,  continually  decreases.  The  quantity 
of  bodies  soluble  in  alcohol  quickly  increases.  A  specially  impor- 
tant increase  is  noticed  in  the  fat,  whose  quantity  is  not  very  great 
even  on  the  fourteenth  day,  but  after  that  it  becomes  considerable. 
The  quantity  of  albuminous  bodies  and  albuminoids  insoluble  in 
water  grows  continually  and  regularly  in  such  a  way  that  their 
absolute  quantity  increases  while  their  relative  quantity  remains 
nearly  unchangod.  Liebermann  found  no  gelatin  in  the  embryo 
of  the  hen.  The  embryo  does  not  contain  any  gelatin-forming 
substance  until  the  tenth  day,  and  from  the  fourteenth  day  on  it 
contains  a  body  which  when  boiled  with  water  gives  a  substance 
similar  to  chondrin.  A  body  similar  to  mucin  occurs  in  the 
embryo  when  about  six  days  old,  but  then  disappears.  The  quan- 
tity of  hsemoglobin  shows  a  continual  increase  compared  to  the 
weight  of  the  body.  Liebermajstn  found  that  the  relationship  of 
'  Pfluger's  Arch.,  Bd.  43. 


AMNIOTIC  FLUID.  419 

the  haemoglobin   to  the  bodily  weight  was  1 :  728  on   the  eleventh 
day  and  1:421  on  the  twenty-first  day. 

The  tissue  of  the  placenta  bas  not  thus  far  been  the  subject  of  detailed  chena- 
ical  investigation.  In  the  edges  of  the  ph\centa  of  bitches  and  of  cats  a  crys- 
tallizable  orange-colored  pigment  (bilirubin  ?)  bas  been  found,  and  also  agreen 
amorphous  pigment,  Meckel's  luematocJilorin,  which  is  considered  as  biliverdin 
by  Etti.'      Preyer-  questions  the  identity  of  these  pigments  with  biliverdin. 

From  the  cotyledons  of  the  placenta  in  ruminants  a  white  or  faint  rose-col- 
ored creamy  fluid,  the  uterine  mik,  can  be  obtained  by  pressure.  It  is  alkaline 
in  reaction,  but  becomes  acid  quickly.  Its  s]iecific  gravity  is  1.033-1.040.  It 
contains  as  form-elements  fat-globules,  small  granules,  and  epithelium-cells. 
We  have  found  81  2-120.9  p.  m.  solids,  61.2-105.6  p.  m.  proteid,  about  10 
p.  m.  fat.  and  3.7-8  2  ]).  m.  ash  in  tiie  uterine  milk. 

Tiie  fluid  occurring  in  the  so-called  grape-mole  [mola  racemosa)  has  a  low- 
specific  gravity,  1  009-1.012,  and  contains  19.4-26.8  p.  m.  solids  with  9-10  p.  m. 
protein  bodies  and  6-7  p.  m.  ash. 

The  amniotic  fluid  is  in  women  thin,  whitisli,  or  pale  yellow; 
sometimes  it  is  somewhat  yellowish  brown  and  cloudy.  White 
flakes  separate.  The  form-elements  are  muciis-coi'puscUs,  epithe- 
lium-cells, fat-drops,  and  lanugo  hair.  The  odor  is  stale,  the 
reaction  neutral  or  faintly  alkaline.  Tlie  specific  gravity  is  1.002- 
1.028. 

The  amniotic  fluid  contains  the  constituents  of  ordinary  transu- 
dations. The  amount  of  solids  at  birth  is  hardly  20  p.  m.  In  the 
earlier  stages  of  pregnancy  the  fluid  contains  more  solids,  especially 
proteids.  Among  the  albuminous  bodies,  Weyl  ^  found  one  sub- 
stance similar  to  vitellin,  and  with  great  probability  also  ser- 
albumin,  besides  small  quantities  of  mucin.  Glucose  is  regularly 
found  in  the  amniotic  fluid  of  cows,  but  not  in  human  beings.  On 
tlie  contrary,  the  human  amniotic  fluid  contains  some  urea  and 
allantoin.  The  quantity  of  these  may  be  increased  in  hydramnion 
(Prochowxick,*  Harxack),^  which  depends  on  an  increased  secre- 
tion by  tlie  kidneys  and  skin  of  the  foetus.  Creatin  and  lactates 
are  questionable  constituents  of  the  amniotic  fluid.  The  quantity 
of  urea  in  the  amniotic  fluid  is,  according  to  Prochowxick,  0.16 
p.  m.  In  the  fluid  in  hydramnion,  Prochowxick  and  Harxack 
found  respectively  0.34  and  0.48  p.  m.  urea.  The  chief  mass  of 
the  solids  consists  of  salts.  The  quantity  of  chlorides  (NaCl)  is 
5.7-6.6  p.  m. 

'  Maly's  Jabresber.,  Bd.  2,  S.  287. 

'  Die  Blutkrystalle  (Jena,  1871),  S.  189  ;  Du  Bois-Reymond's  and  Reichert's 
Arch.,  1876. 
»  lUd. 

*  Arch.  f.  Gynak.,  Bd.  11;  also  Maly's  Jahresber.,  Bd.  7,  S.  155. 
»  Berlin  klin.  Wochenschr.,  1888,  No.  41. 


CHAPTEE  XrV. 
MILK. 

The  chemical  constituents  of  the  mammary  glands  have  been 
little  studied.  The  protoplasm  of  the  cells  is  rich  in  proteid, 
which  consists  in  great  part  of  casein  or  a  substance  nearly  related. 
If  all  the  milk  is  removed  from  the  mammary  gland  by  thorough 
washing,  the  cells  still  contain  a  large  quantity  of  proteids  which 
swell  up  to  a  slimy,  ropy,  or  fibrous  mass  when  very  dilute  alkali 
(1-2  p.  m.  KOH)  is  added.  These  proteids  consist  mainly  of 
nucleoproteid,  which  is  gradually  changed  by  the  action  of 
the  alkali.  This  nucleoproteid  gives  a  reducing  substance  on. 
boiling  with  dilute  acids.  If  the  mammary  gland  is  boiled  with 
water,  the  protoplasm  of  the  cell  is  decomposed  and  a  nucleo- 
proteid passes  into  solution,  which  may  be  precipitated  by  the 
adc^tion  of  acetic  acid,  and  which  is  characterized  by  its  greater 
insolubility  in  acetic  acid,  compared  with  casein."  This  nucleo- 
proteid, which  may  well  be  considered  as  a  protoplasm-nucleo- 
proteid  changed  by  heat,  also  gives  on  boiling  with  dilute  mineral 
acids  a  reducing  substance  whose  nature  is  not  known.  The 
relation  this  nucleoproteid  bears  to  lactose  or  the  mother-substance 
of  the  same  has  not  been  determined.  According  to  Bert,  '  the 
secreting  glands  contain  a  body  which  on  boiling  with  dilute 
mineral  acids  yields  a  reducing  substance.  Such  a  substance, 
which  acts  as  a  step  towards  the  formation  of  lactose,  has  also  been 
observed  by  Thierfelder.^  Fat  seems  to  be  a  never-failing  con- 
stituent of  the  cell,  at  least  in  the  secreting  gland,  and  this  fat  may 
be  observed  in  the  protoplasm  as  large  or  small  globules  similar  to 
milk-globules.     The  extractive  bodies  of  the  mammary  glands  have 

'  C'ompt.  rend.,  Tome  98. 

'  Pfluger's  Arch.,  Bd.  32,  and  Maly's  Jahresber.,  Bd.  13,  S.  156. 

420 


COW'S  MILK.  421 

been  little  investigated,   but    among    them    we    find    considerable 
amounts  of  xauthin  bases. 

As  human  milk  and  milk  of  animals  are  essentially  of  the  same 
constitution,  it  seems  best  to  speak  first  of  the  one  most  thoroughly 
investigated,  namely,  cow's  milk,  and  then  of  the  essential  proper- 
ties of  the  remaining  important  varieties  of  milk. 

Cow's  Miik. 

Cow's  milk  forms,  as  all  milks  do,  an  emulsion  which  consists 
•of  very  finely  divided  fat  suspended  in  a  solution  consisting  chiefly 
of  proteid  bodies,  milk-sugar,  and  salts.  Milk  is  non-transparent, 
white,  whitisli  yellow,  or  in  thin  layers  somewhat  bluish  white,  of 
a  faint,  insipid  odor  and  mild,  faintly  sweetish  taste.  The  specific 
gravity  is  1.038  to  1.0345  at  +  15°  C. 

The  reaction  of  perfectly  fresh  milk  is  generally  amphoteric. 
The  extent  of  the  acid  and  alkaline  part  of  this  amphoteric  reac- 
tion has  been  determined  by  different  investigators,  especially 
Thornek,'  Sebelin,'  and  Courant.'  The  results  are  different 
on  using  different  indicators,  and  also  the  milk  from  various 
animals,  as  well  as  at  different  times  during  the  lactation  period, 
differs  somewhat.  The  first  and  last  portions  of  the  same  milking 
have  a  different  reaction.     Courant  has  determined  the  alkaline 

N 
part  by  —  sulphuric  acid,  using  blue  lacmoid  as  indicator  and  the 

N 
acid  part  by  —  caustic  soda,   using  phenolphthalein  as  indicator. 

He  found,  as  average  for  the  first  and  last  portions  of  the  milking 

of  twenty  cows,  that  100  cc.  milk  had  the  same  alkaline  reaction 

N 
for  blue  lacmoid  as  41  cc.  —  caustic  soda,  and  the  same  acid  reac- 

N 
tion  for  phenolphthalein  as  19.5  cc.  —  sulphuric  acid. 

Milk  gradually  changes  when  exposed  to  the  air,  and  its  reac- 
tion becomes  more  and  more  acid.  This  depends  on  a  gradual 
transformation  of  the  milk-sugar  into  lactic  acid,  caused  by  micro- 
organisms. 

1  Chem.  Ztg.,  Ed.  16,  S.  1469. 
^  Ibid.,  Bd.  16,  S.  597. 

2  Ueber  die  Reaktion  der  Kuh-  und  Frauenmilcli,  etc.  Inaug.-Diss.  Bonn, 
1891;  also  Ptluger's  Arch.,  Bd.  50. 


422  MILE. 

Entirely  fresh  amplioteric  milk  does  not  coagulate  on  boiling, 
but  forms  a  skin  consisting  of  coagulated  casein  and  lime-salts, 
which  rapidly  re-forms  after  being  removed.  Even  after  passing  a 
current  of  carbon  dioxide  through  the  fresh  milk  it  does  not 
coagulate  on  boiling.  In  proportion  as  the  formation  of  lactic  acid 
advances  this  behavior  changes,  and  soon  a  stage  is  reached  when 
the  milk,  which  has  previously  had  carbon  dioxide  passed  through 
it,  coagulates  on  boiling.  At  a  second  stage  it  coagulates  alone  on 
heating;  then  it  coagulates  by  passing  carbon  dioxide  alone  without 
boiling;  and  lastly,  when  the  formation  of  lactic  acid  is  sufficient, 
it  coagulates  spontaneously  at  the  ordinary  temperature,  forming  a 
solid  mass.  It  may  also  happen,  especially  in  the  warmth,  that  the 
casein-clot  contracts  and  a  yellowish  or  yellowish-green  acid  liquid 
(acid  whey)  separates. 

If  the  drawn  is  sterilized  by  heating  and  contact  with  micro- 
organisms prevented,  the  formation  of  lactic  acid  may  be  entirely 
stojDped.  The  formation  of  acid  may  also  be  prevented,  at  least  for 
some  time,  by  many  antiseptics,  such  as  salicylic  acid  (1 :  5000), 
thymol,  boracic  acid,  and  other  bodies. 

If  freshly  drawn  amjjhoteric  milk  is  treated  with  rennet,  it 
coagulates  quickly,  especially  at  the  temperature  of  the  body,  to  a 
solid  mass  (curd)  from  which  a  yellowish  fluid  (sweet  whey)  is 
gradually  pressed  out.  This  coagulation  occurs  without  any  change 
in  the  reaction  of  the  milk,  and  therefore  it  is  distinct  from  the 
acid  coagulation. 

Milk  sometimes  undergoes  a  peculiar  kind  of  coagulation,  being  converted 
into  a  thick,  ropy,  slimy  mass  (thick  milk).  This  conversion  depends,  accord- 
ing to  Schmidt- MxJLnEiM,^  upon  a  peculiar  change  in  which  the  milk-sugar 
is  made  to  undergo  a  slimy  transformation.  This  transformation  is  caused  by 
a  special  organized  ferment. 

In  cow's  milk  we  find  as  form-elements  a  few  colostrum  cor- 
puscles (see  Colostrum)  and  a  few  pale  nucleated  cells.  The 
number  of  tl:ese  form-elements  is  very  small  compared  with  the 
immense  amount  of  the  most  essential  form-constituents,  the  milk- 
globules. 

The  Milk-globules.  These  consist  of  extremely  small  drops  of 
fat  whose  number  is,  according  to  Woll,"   1.03-5.75   million  in 

'  Pfluger's  Arch.,  Bd.  27. 
.   *  On  the  Conditions   influencing  the   Number  and    Size  of   Fat-globules  in. 
Cow's  Milk.     Wisconsin  Expt.  Station,  Vol.  6,  1893. 


MIL  KG  LOBULES.  428 

1  c.mm.,  and  whose  diameter  is  0.0024-0.0046  mm.  and  0.0().']7 
mm.  as  average  for  animals  of  different  races.  It  is  unquestionable 
that  the  milk-globules  contain  fat,  and  we  consider  it  as  positive 
that  all  the  milk-fat  exists  in  them.  Another  and  disputed  ques- 
tion is  whether  the  milk-globules  consist  entirely  of  fat  or  whether 
they  also  contain  proteid. 

According  to  the  observations  of  Ascherson,  '  drops  of  fat,  when 
dropped  in  an  alkaline  proteid  solution,  are  covered  with  a  fine 
albuminous  coat,  a  so-called  hajjtogen-me^nhrane.  As  milk  on 
shaking  with  ether  does  not  give  up  its  fat,  or  only  very  slowly,  in 
the  presence  of  a  great  excess  of  ether,  and  as  this  takes  place  very 
readily  after  the  addition  of  acids  or  alkalies,  which  dissolve  proteids, 
it  was  formerly  thought  that  the  fat-glohales  of  the  milk  were  en- 
velojDcd  in  a  proteid  coat.  A  true  membrane  has  not  been  detected ; 
and  since,  when  no  means  of  dissolving  the  proteid  is  resorted  to — 
for  example,  when  the  milk  is  precipitated  by  carbon  dioxide  after 
the  addition  of  very  little  acetic  acid,  or  when  it  is  coagulated  by 
rennet^ — the  fat  can  be  very  easily  extracted  by  ether,  the  theory  of  a 
special  albuminous  membrane  for  the  fat-globules  has  been  gener- 
ally abandoned.  The  observations  of  Quincke  '  on  the  behavior 
of  the  fat-globules  in  an  emulsion  prepared  with  gum  have  led,  at 
the  present  time,  to  the  conclusion  that  each  fat-globule  in  the 
milk  is  surrounded  by  a  stratum  of  casein  solution  by  means  of 
moleciTlar  attraction,  and  this  prevents  the  globules  from  uniting 
with  each  other.  Everything  that  changes  the  physical  property  of 
the  casein  in  the  milk  or  precipitates  it  must  necessarily  help  the 
solution  of  the  fat  in  ether,  and  it  is  in  this  way  that  the  alkalies, 
acids,  and  rennet  work. 

If  we  accept  this  view,  which  requires  further  proof,  we  must  not  overJook. 
the  fact  that  the  fat-globules  remain  unchanged  when  the  milk  under  agitation 
is  coagulated  with  rennet.  In  this  case  we  find  an  immense  number  of  un- 
changed milk-globules  in  the  whey,  and  if  we  wish  to  admit  of  a  stratum  of 
proteids  around  the  fat-globules  proceeding  from  the  molecular  attraction,  we^ 
must  not  consider  that  it  is  entirely  due  to  casein,  but  to  proteid  in  general. 

If  the  fat-globules  are  filtered  off  and  washt  d  on  a  filter,  we  always  obtain 
(Radenhausen  and  Danilewsky)  *  after  their  treatment  with  ether  a  residue 
consisting  of  proteid.  From  this  behavior  the  deduction  has  been  made  that 
the  fat-globules,  even  though  they  have  no  real  membrane,  consist,  neverthe- 
less, of  fat  and  proteid.  The  extreme  difficulty  of  completely  removing  the 
albuminous  bodies  of  the  milk  by  washing  the  fat  on  the  filter  renders  it  neces- 
sary to  exercise  great  caution  in  drawing  a  conclusion.     The  question  as  to  the 

'  Arch.  f.  Anat.  u.  Physiol..  1840. 

5  Ptiuger's  Arch.,  Bd.  19. 

»  Forschungen  auf  dem  Gebeite  der  Viehhaltung  (Bremen,  1880),  Heft  9. 


424  MILK. 

composition  of  the  milk-globules,  and   especially  as  to  the  possible  amount  of 
proteid,  cannot  be  decided  at  present. 

The  milh-fat  has  a  rather  variable  specific  gravity,  which  ac- 
cording to  Bohr  '  is  0.949-0.996  at  +  15°  0.  The  milk-fat,  which 
is  obtained  under  the  name  of  butter,  consists  in  great  part  of  the 
neutral  fats  palmititi,  olein,  and  stearin.  Besides  these  it  contains, 
as  triglycerides,  myristic  acid,  small  quantities  of  iutyric  acid  and 
■caproic  acid,  traces  of  caprylic  acid,  capric  acids,  lauric  acid,  and 
.arachidic  acids.  Butter  which  has  been  exposed  to  the  action  of 
sunlight  contains  also  formic  acid  (Duclaux).  Milk-fat  also  con- 
tains a  small  quantity  of  lecitJmi  and  cholesterin,  also  a  yellow  col- 
oring matter.  The  quantity  of  volatile  fatty  acids  in  butter  is,  ac- 
cording to  DucLAUX,'  on  an  average  about  70  p.  m.,  of  which 
37-51  p.  m.  is  butyric  acid  and  20-33  p.  m.  is  caproic  acid.  The 
non- volatile  fat  consists  of  -^-^  to  -^  olein,  and  the  remainder  of  a 
mixture  of  palmitin  and  stearin. 

According  to  other  investigators  milk-fat  has  a  different  composition. 
'KOEFOED*  found  in  butter  from  Jutland  besides  oleic  acid  two  other  acids  not 
belonging  to  the  series  CnHsnOj,  having  the  formulae  C16H28O4  and  (probably) 

'C'3gli54V'6. 

In  100  parts  fatty  acids  he  found  66  parts  acids  of  the  series  CnHjnOa,  name- 
ly, 2  stearic  acid,  28  palmitic  acid,  22  myristic  acid,  8  lauric  acid,  1.5  butyric 
acid,  2  caproic  acid,  2  capric  acid,  and  0.5  caprylic  acid.  According  to 
Wanklyn  *  butter  does  not  contain  any  palmitic  acid.  It  contains  instead  an 
Acid  called  by  him  aldepalmitic  acid,  with  the  formula  (Ci6H3o02)n,  and  not  be- 
longing to  the  oleic  acid  series.  The  relative  quantities  of  the  different  fatty 
acids  do  not  seem  to  be  constant,  and  they  differ  at  various  times  during  lac- 
tation. 

The  quantity  of  volatile  fatty  acids  in  butter- fat  is  of  great  practical  im- 
portance in  the  methods  for  detecting  the  presence  of  foreign  fats  in  butter. 
This  detection  is  performed  generally  according  to  Keichekt's  process  based 
on  Hehner  and  Angell's  method.  The  fat  is  saponified  with  alcoholic  pot- 
ash and  the  alcohol  evaporated.  The  soaps  are  dissolved  in  water,  and  then 
distilled  with  an  excess  of  phosphoric  acid.  The  quantity  of  volatile  fatty 
acids  in  the  distillate  is  determined  by  titration  with  decinormal  alkali.  With 
butter  of  proper  composition  2.5  grms.  should  yield  a  distillate  requiring 
14-13  c.c.  for  neutralization,  and  at  least  not  less  than  12  c.c.  of  the  decinormal 
alkali.  In  proportion  as  the  butter  contains  a  greater  quantity  of  foreign  fats 
the  quantity  of  alkali  required  becomes  smaller.  We  cannot  here  describe  in 
detail  the  different  modifications  of  this  process  as  well  as  the  newer  methods, 

The  milk-plasma,  or  that  fluid  in  which  the  fat-globules  are  sus- 
pended, contains  at  least  three  different  albuminous  bodies,  casein, 
lactoglohulin,  and  lactalbumm,  and  two  carbohydrates,  of  which  only 

'  Studier  over  Maelk.  Kjobenhavn,  1880,  and  Maly's  Jahresber.,  Bd.  10, 
S.  182. 

'  Compt.  rend.,  Tome  104. 

3  Bull,  de  I'Acad.  Roy.  Danoise,  1891. 

*  Chem.  News,  Vol.  63. 


CASELN.  425 

one,  the  milk-sugar^  is  of  great  importance.     The  milk-phisma  also 
contains  extractive  bodies,  traces  of  7(7'ea,  creativ,  a-eatinin,  hypo- 
xantliin  (?),  lecithin,  cholesterin,  citric  acid  (Soxhlet  and  Hen 
kel),'  and  lastly  also  mineral  bodies  and  gases. 

Casein.  This  protein  substance,  which  thus  far  has  been  de- 
tected positively  only  in  milk,  belongs  to  the  nucleoalbnmins,  and 
differs  from  the  albuminates  by  its  containing  phosporus  and  by 
its  behavior  with  the  rennet  enzyme.  Casein  from  cow's  milk  has 
the  following  composition:  C  53.0.  H  7.0,  N  15.7,  S  0.8,  P  0.85, 
and  0  22.65^.  Its  specific  rotation  is,  according  to  Hoppe-Seyler," 
somewhat  variable;  in  neutral  solution  it  is  a  (D)  =  —  80°.  The 
question  whether  the  casein  from  different  varieties  of  milk  is  iden- 
tical or  whether  there  are  several  different  caseins  has  not  been 
positively  determined. 

Casein  when  dry  appears  like  a  fine  white  powder  whicli,  after 
heating  to  100°  C.  or  somewhat  above,  shows  the  properties  and 
solubilities  of  freshly  precijiitated,  still-moist  casein.  '  Casein  is  only 
slightly  soluble  in  water  or  in  neutral-salt  solutions.  According  to 
Arthus^  it  is  rather  easily  soluble  in  a  1^  solution  of  sodium  fluo- 
ride, ammonium,  or  potassium  oxalate.  It  acts  like  a  rather  strong 
acid,  dissolves  readily  in  water  on  the  addition  of  very  little  alkali, 
forming  a  neutral  or  acid  liquid,  and  lastly  it  dissolves  in  water  in 
the  presence  of  calcium  carbonate,  from  which  it  expels  the  carbon 
dioxide.  If  casein  is  dissolved  in  lime-water  and  this  solution  care- 
fully treated  with  very  dilute  phosphoric  acid  until  it  is  neutral  in 
reaction,  the  casein  appears  to  remain  in  solution,  but  is  probably 
only  swollen  as  in  milk,  and  the  liquid  contains  at  the  same  time  a 
large  quantity  of  calcium  phosphate  without  any  precipitate  or  any 
visible  suspended  particles.  The  casein  solutions  containing  lime 
are  opalescent  and  have  on  warming  the  appearance  of  milk  deficient 
in  fat.  Therefore  it  is  not  impossible  that  the  white  color  of  the 
milk  is  due  partly  to  the  casein  and  calcium  phosphate.  Soldner 
has  prepared  two  calcium  combinations  of  casein  with  1.55  and 
2.36^  CaO,  and  these  combinations  are  designated  di-  and  tricalcium 
casein  by  Courant.' 

'  Cited  from  F.   SOldner,  Die   Salze   der  Milch,  etc.    LandwirthscL.   Ver- 
suclisstation,  Bd.  35.     Separatabzug,  S.  18. 

'  Handb.  d.  pbysiol.  u.  pathol.  cbem.  Analyse,  6.  Autl.,  S.  259. 
'  Theses  presentees  a  la  faculte  des  sciences  de  Paris,  1893. 
«L.  c. 


426  MILK. 

Casein  solutions  do  not  coagulate  on  boiling,  bnt  are  covered,  like 
milk,  with  a  skin.  They  are  precipitated  by  very  little  acid,  but 
the  presence  of  neutral  salts  retards  the  precipitation.  A  casein 
solution  containing  salt  or  ordinary  milk  requires,  therefore,  more 
acid  for  precipitation  than  a  salt-free  solution  of  casein  of  the  same 
concentration.  The  precipitated  casein  dissolves  very  easily  again 
in  a  small  excess  of  the  acid,  but  less  easily  in  an  excess  of  acetic 
acid.  The  acid  solutions  are  precipitated  by  mineral  acids  in 
excess.  Casein  is  precipitated  from  neutral  solutions  or  from  milk 
by  common  salt  or  magnesium  sulphate  in  substance  without  chang- 
ing its  properties.  Metallic  salts,  such  as  copper  sulphate,  com- 
pletely precipitate  the  casein  from  neutral  solutions. 

The  property  which  is  the  most  characteristic  of  casein  is  that 
it  coagulates  with  rennet  in  the  presence  of  a  sufficiently  great 
amount  of  lime-salts.  In  solutions  free  from  lime-salts  the  casein 
does  not  coagulate  with  rennet;  but  it  is  changed  so  that  the  solu- 
tion (even  if  the  enzyme  is  destroyed  by  heating)  yields  a  coagulated 
mass,  having  the  properties  of  curd,  if  lime-salts  are  added.  The 
rennet  enzyme,  rennin,  has  therefore  an  action  on  casein  even  in 
the  absence  of  lime-salts,  and  these  last  are  only  necessary  for  the 
coagulation  or  the  separation  of  the  curd.  This  fact,  which  was 
first  proved  by  the  author,'  has  lately  been  confirmed  by  Arthus 
and  Pages. ^  Peters^  claims  to  have  found  that  paracasein,  when 
dissolved  in  lime-water,  may  be  repeatedly  coagulated  by  rennet. 
According  to  Peters  rennet  also  coagulates  alkali  albuminate,  as 
also  vegetable  proteid  bodies  precipitated  by  acids  (wheat  and  peas) 
when  dissolved  in  lime-water.  Several  enzymes  existing  in  the 
planet  kingdom  also  have  the  same  action  as  rennet. 

The  curd  formed  on  the  coagulation  of  milk  contains  large 
quantities  of  calcium  phosphate.  According  to  Soxhlet  and 
SoLDNER,'  the  soluble  lime-salts  are  only  of  essential  importance  in 
coagulation,  while  the  calcium  phosphate  is  without  importance. 
According  to  Courant'  the  calcium  casein  on  coagulation  may 
carry  down  with  it,  if  the  solution  contains  dicalcium  phosphate,  a 

'  Maly's  Jabresber. ,  Bdd.  2  and  4;  also  Hammarsten,  Zur  Kenntniss  des 
Kaseins  und  der  Wirkung  des  Labfermentes.  Nova  Acta  Reg.  Soc.  Scient. 
XJpsala,  1877,     Festschrift. 

'  Arcb.  de  Physiol.  (5),  Tome  2,  and  Mem.  Soc.  bioL,  Tome  43. 

'  Unters.  liber  das  Lab  und  die  Lababnlichen  Fermente.     Rostock,  1894. 

'•  L.  c. 

'-  L.  c. 


PROPERTIES   OF  CASEIN.  427 

part  of  this  as  tricalcium  phosphate,  leaving  monocalcinm  phosphate 
in  the  solution.  The  chemical  processes  which  take  place  in  the 
rennet  coagulation  have  not  been  thoroughly  investigated ;  still 
several  observations  seem  to  show  that  casein  splits  partly  into  a 
difficultly  soluble  body,  paracasein  or  curd,  whose  composition 
closely  resembles  that  of  casein  and  which  forms  the  chief  product, 
and  partly  into  an  easily  soluble  substance,  similar  to  albumose, 
whey-proleid,  which  is  deficient  in  carbon  and  nitrogen  (50. o^  C 
and  13.2^  N,  Kostner^)  and  which  is  produced  in  very  small 
quantities.  Paracasein"  is  not  further  changed  by  the  rennet 
enzyme,  and  it  has  not  the  same  property  of  holding  calcium  phos- 
phate in  solution  as  casein  has. 

In  the  digestion  of  casein  with  pepsin  hydrochloric  acid  pseudo- 
nuclein  is  split  off.  The  quantity  of  pseudonuclein  split  off  is, 
according  to  Moraczewski,^  very  considerable,  from  1.29  to  21.10^ 
of  the  digested  casein.  Salkow^ski  and  Hahn  *  and  Siebelien  " 
have  also  found  with  Moraczewski  that  the  quantity  of  pseudo- 
nuclein split  off  in  the  peptic  digestion  of  casein  is  very  variable. 
SEBELiEisr  as  well  as  Willdejstow  and  Moraczewski  could  not 
bring  all  the  pseudonuclein  in  solution  by  continuous  digestion. 
The  quantity  of  phosphorus  in  the  pseudonuclein  also  varies  between 
0.88  and  6.86^,  and  of  the  casein  phosphorus  varying  quantities, 
6  to  60^,  were  obtained  in  the  pseudonuclein.  All  the  phosphorus 
of  the  casein  was  never  obtained  as  pseudonuclein,  and  Mora- 
czewski draws  the  conclusion  from  his  investigations  that  the  pseu- 
donuclein from  the  beginning  does  not  contain  all  the  phosphorus 
of  the  casein. 

Casein  may  be  prepared  in  the  following  way:  The  milk  is 
diluted  with  4  vols,  water  and  the  mixture  treated  with  acetic  acid 
to  0.75  to  1  p.  m.  Casein  thus  obtained  is  purified  by  repeated 
solution  in  water  with  the  aid  of  the  smallest  quantity  of  alkali 
possible,   by  filtrating  and   reprecipitatiug  with  acetic  acid,   and 

'  See  Maly's  Jahresber.,  Bd.  11,  S.  14. 

'  It  has  been  recently  proposed  to  designate  the  ordinary  casein  as  caseino- 
gen,  and  the  curd  as  casein.  Although  such  a  proposition  is  theoretically  cor- 
rect, it  leads  in  practice  to  confusion.  On  this  account  the  author  calls  the 
curd  paracasein,  according  to  Schulze  and  R5se  (Landwirthsch,  Versuchsstat.,. 
Bd.  31). 

»  Zeitschr.  f.  physiol.  Chem.,  Bd.  20. 

*  Pflilger's  Arch.,  Bd.  50. 

*  Zeitschr.  f.  physiol.  Chem.,  Bd.  20. 


428  MILK 

thoroughly  washing  with  water.  Most  of  the  milk-fat  is  retained 
l)y  the  filter  on  the  first  filtration,  and  the  casein  contaminated  with 
traces  of  fat  is  purified  by  treating  with  alcohol  and  etlior. 

Lactoglohulin  was  obtained  by  Sebeliei^  '  from  cow's  milk  by 
saturating  it  with  NaCl  in  substance  (which  precipitated  the 
casein),  and  saturating  the  filtrate  with  magnesium  sulphate.  As 
far  as  it  has  been  investigated  it  had  the  properties  of  serglobulin, 
with  which  it  is  perhaps  identical. 

Lactalbumin  was  first  prepared  in  a  pare  state  from  milk  by 
Sebelien.^  Its  composition  is,  according  to  Sebelien,  C  53.19, 
H  7.18,  N  15  77,  S  1.73,  0  23,13^.  Lactalbumin  has  the  proper- 
ties of  the  albumins.  It  coagulates,  according  to  the  concenti'ation 
and  the  amount  of  salt  in  solution,  at  +  "^3°  to  84°  C.  It  is  similar 
to  seralbumin,  but  differs  from  it  in  having  a  considerably  lower 
specific  rotatory  power:  a  (D)  =  —  37°. 

The  principle  of  the  preparation  of  lactalbumin  is  the  same  as 
for  the  preparation  of  seralbumin  from  serum.  The  casein  and  the 
globulin  are  removed  by  MgSO^  in  substance  and  the  filtrate  treated 
as  previously  stated  (page  122). 

The  occurrence  of  other  albuminous  bodies,  such  as  albumoses  and  peptones, 
in  milk  has  not  been  positively  proved.  These  bodies  are  easily  produced  as 
iaboration  products  from  the  other  proteids  of  the  milk.  Such  a  laboration 
product  is  Millon's  and  Comaille's  lactoprotein,  which  is  a  mixture  of  a 
little  casein  v?ith  changed  albumin,  and  albumose,*  which  is  formed  by  the 
chemical  operations. 

Milk-sugar,  Lactose,  Oj^H^^Oj,  +  H^O.  This  sugar  with  the 
absorption  of  water  can  be  split  into  two  glucoses,  dextrose  and 
galactose.  It  yields  nuicic  acid  by  the  action  of  dilute  nitric  acid, 
besides  other  organic  acids.  Levulinic  acid  is  formed,  besides  formic 
acid  and  humin  substances,  by  the  stronger  action  of  acids.  By  the 
action  of  alkalies  amongst  other  products  we  find  lactic  acid  and 
pyrocatechin. 

Milk-sugar  occurs,  as  a  rule,  only  in  milk,  but  it  has  also  been 
found  in  the  urine  of  pregnant  women  on  stagnation  of  milk. 
According  to  the  statements  of  Pappel  and  Righmojs'D  *  the  milk 
of  the  Egyptian  buffalo  does  not  contain  milk-sugar,  but  a  sugar 
which  they  call  teiufikose. 

^  Zeitschr.  f.  physiol.  Chem.,  Bd.  9. 
«L.  c. 

^  See  Hamniarsten,   Ueber  das   Laktoprotein.     Nord.  med.    Arkiv.,  Bd.  8, 
No.  10;  also  Maly's  Jahresber.,  Bd.  6,  S.  13. 
''  Journ.  Chem.  Soc,  London,  1894,  p.  754. 


MILK-SVOAR.  42J^ 

Milk-sugar  occurs  ordinarily  as  colorless  rhombic  crystals  with 
1  mol.  of  water  of  crystallization,  which  is  driven  off  by  slowly 
heating  to  100°  C,  but  more  easily  at  130-140°  C.  At  170°  to 
180°  C.  it  is  converted  into  a  brown  amorphous  mass,  lactocaramel, 
CgHj^Oj.  Milk-sugar  dissolves  in  6  parts  cold  and  in  2.5  parts 
boiling  water;  it  has  a  faint  sweetish  taste.  It  does  not  dissolve  ia 
ether  or  absolute  alcohol.  Its  solutions  are  dextrogyrate.  The 
rotatory  power,  which  on  heating  the  solution  to  100°  C.  becomes 
constant,  is  a  (D)  =  +  52.5°.  Milk-sugar  combines  with  bases; 
the  alkali  combinations  are  insoluble  in  alcohol. 

Milk-sugar  is  not  fermentable  with  pure  yeast.  It  undergoes, 
on  the  contrary,  alcoholic  fermentation  by  the  action  of  certain 
schizomycetes,  and  lactic  acid  is  produced  thereby.  The  prep- 
aration of  milk-wine,  "  kumyss,^^  from  mare's  milk  and  "  kephir''^ 
from  cow's  milk  is  based  upon  this  fact.  Micro-organisms  produce 
a  lactic-acid  fermentation  in  lactose,  and  this  explains  the  ordinary 
souring  of  milk. 

Lactose  responds  to  the  reactions  of  grape-sugar,  such  as 
Moore's  or  Trommer's,  and  the  bismuth  test,  which  will  all  be 
described  in  Chapter  XV  on  the  urine.  It  also  reduces  mercuric 
oxide  in  alkaline  solutions.  After  warming  with  phenylhydrazin 
acetate  it  gives  on  cooling  a  yellow  crystalline  precipitate  of  phenyl- 
lactosazon,  C^ JIj^N^O,.  It  differs  from  cane-sugar  by  giving  posi- 
tive reactions  with  Moore's  or  Trommer's  and  the  bismuth  test, 
and  also  that  it  does  not  darken  when  heated  with  anhydrous  oxalic 
acid  to  100°  C.  It  differs  from  grape-sugar  and  maltose  by  its- 
solubility  and  crystalline  form ;  but  especially  by  its  not  fermenting 
with  yeast  and  by  yielding  mucic  acid  with  nitric  acid. 

For  the  preparation  of  milk-sugar  we  make  use  of  the  by-product 
in  the  preparation  of  cheese,  the  sweet  whey.  The  proteid  is 
removed  by  coagulation  with  heat  and  the  filtrate  evaporated  to  a 
syrup.  The  crystals  which  separate  after  a  certain  time  are  recrys- 
tallized  from  water  after  decolorizing  with  animal  charcoal.  A 
pure  preparation  may  be  obtained  from  the  commercial  milk-sugar 
by  repeated  recrystallization.  The  quantitative  estimation  of  milk- 
sugar  may  in  part  be  performed  by  the  polaristrobometer  and  partly 
by  means  of  titration  with  Fehling's  solution.  10  c.  c.  of 
Fehling's  solution  corresponds  to  0.067  grm.  milk-sugar  in 
0.5-1.5^  solution  and  boiling  for  6  minutes  (in  regard  to  Fehling's 
solution  and  the  titration  of  sugar,  see  Chapter  XV). 

RlTTHAUSEN  '  has  found  another  carbohydrate  in  milk  which  is  soluble  ia 

>  Journ.  f.  prakt.  Chem.,  N.  F.,  Bd.  15. 


430  MILK. 

■water,  non-crystallizable,  whicli  has  a  faint  reducing  action,  and  which  yields 
on  boiling  with  an  acid  a  body  having  a  greater  reducing  power.  Landwehr  ' 
considers  this  as  animal  gum,  and  B^champ  *  as  dextrin.  According  to  J. 
HETiZ  '■^  granules  occur  in  milk,  which  act  like  starch  with  iodine  and  which 
are  perhaps  animal  starch. 

The  mineral  bodies  of  milk  will  be  treated  in  connection  with 
its  quantitative  composition. 

The  methods  for  the  quantitative  analysis  of  milk  are  very 
numerous,  and  as  they  cannot  all  be  treated  of  here,  we  will  give 
the  chief  points  of  a  few  of  the  most  trustworthy  and  most  fre- 
quently employed  methods. 

In  determining  the  solids  a  carefully  weighed  quantity  of  milk 
is  mixed  with  an  equal  weight  of  heated  quartz  sand,  fine  glass 
powder,  or  asbestos.  The  evaporation  is  first  done  on  the  water- 
bath  and  finished  in  a  current  of  carbon  dioxide  or  hydrogen  not 
above  100°  C. 

The  mineral  bodies  are  determined  by  ashing  the  milk,  using 
the  precautious  mentioned  in  the  text-books.  The  results  obtained 
for  the  phosphoric  acid  are  incorrect  on  account  of  the  burning  of 
phosphorized  bodies,  such  as  casein  and  lecithin.  We  must  there- 
fore, according  to  Soldner/  subtract  25^  from  the  total  phosphoric 
acid  found  in  the  milk.  The  quantity  of  sulphate  in  the  ash  also 
depends  on  the  burning  of  the  proteids. 

In  the  determination  of  the  total  amount  of  proteids  we 
make  use  of  Ritthausen's  '  method,  namely,  precipitate  the  milk 
with  copper  sulphate.  This  method  gives  incorrect  results  because 
the  copper  hydroxide  does  not  give  up  all  its  water  of  hydration  on 
drying  the  precipitate,  but  only  after  ashing  the  same.  The  results 
for  the  proteids  are  therefore  somewhat  too  high.  I.  Muistk  °  has 
modified  this  process  in  this  wise,  that  he  precipitates  all  the  pro- 
teids by  means  of  copper  oxyhydrate  at  boiling  heat  and  determines 
the  nitrogen  in  the  precipitate  by  means  of  Kjeldahl's  method. 
This  modification  gives  exacter  results. 

The  method  of  Puls  ''  and  Steistberg  '  consists  in  first  diluting 
the  neutralized  milk  with  some  water  and  then  treating  with  alcohol 
until  the  mixture  contains  70-85  vols,  per  cent  alcohol.  The  pre- 
cipitate is  collected  on  a  filter,  washed  with  warm  70^  alcohol, 
extracted  with  ether,  dried,  weighed,  burnt,  and  the  residue 
reweighed.     The  traces  of  proteid  which  remain  in  the  filtrate  and 

1  Pfliiger's  Arch.,  Bd.   39  and  40. 

«  Bull.  soc.  chim.  (Ser.  3),  Tome  6. 

»Chem.  Ztg.,Bd.  16,  S.  1594. 

^  Landwirthsch.  Versuchsstat.,  Bd.  35. 

s  Journal  f.  prakt.  Chem.,  N.  F.,  Bd.  15. 

•  Virchow's  Arch  ,  Bd.  134. 
•>  Pfliiger's  Arch.,  Bd.  13. 

*  Nord.  med.  Arkiv.,  Bd.  9;  also  Maly's  Jahresber.,  Bd.  7,  S.  169, 


ANALYSIS   OF  MILK.  431 

wash-liquor  are  precipitated  by  tannic  acid.  63^  of  the  tannic  acid 
precipitate  is  considered  as  proteid,  and  this  must  be  added  to  the 
proteid  found  directly.  This  method  gives  exact  and  good  results, 
but  is  more  complicated. 

According  to  Sebelie2s''s  '  method,  3-5  grms.  of  milk  are 
diluted  with  an  equal  volume  of  water,  a  little  common-salt  solution 
added,  and  precipitated  with  an  excess  of  tannic  acid.  The  pre- 
cipitate is  washed  with  cold  water,  and  then  the  quantity  of  nitrogen 
determined  by  Kjeldahl's  method.  The  total  nitrogen  found 
when  multiplied  by  6.37  (casein  and  lactalbumin  contain  both  15.7% 
nitrogen)  gives  the  total  quantity  of  albuminous  bodies.  This 
method,  which  is  readily  performed,  gives  very  good  results. 
I.  MuNK  used  this  method  in  the  analysis  of  woman's  milk.  In 
this  case  the  quantity  of  nitrogen  found  must  be  multiplied  by  6.34. 
According  to  Monk's  analyses  nearly  yL  of  the  total  nitrogen  of 
cow's  milk  and  jL  of  woman's  milk  is  derived  from  the  extractives. 

To  determine  the  casein  and  albumins  separately  we  may  make 
use  of  the  method  first  suggested  by  Hoppe-Seyler  and  Tolmat- 
SCHEFF,^  in  which  the  casein  is  precipitated  by  magnesium  sulphate. 
According  to  8EBELiEN,^the  milk  is  diluted  with  its  own  volume  of 
a  saturated  magnesium-sulphate  solution,  then  saturated  with  the 
salt  in  substance,  the  precipitate  filtered  and  washed  with  a 
saturated  magnesium-sulphate  solution.  The  nitrogen  is  deter- 
mined in  the  precipitate  by  Kjeldahl's  method,  and  the  quantity 
of  casein  determined  by  multiplying  the  result  by  6.37.  The 
quantity  of  lactalbumin  may  be  calculated  as  the  difference  between 
the  casein  and  the  total  proteids  found.  The  lactalbumin  may  also 
be  precipitated  by  tannic  acid  from  the  filtrate  containing  MgSO^ 
from  the  casein  precipitate,  diluted  with  water,  and  the  nitrogen 
determined  by  Kjeldahl's  method  and  the  result  multiplied  by 
6.37. 

The  quantity  of  globulins  in  milk  cannot  be  exactly  determined. 
A  minimum  result  can  be  obtained  by  first  precipitating  tha  casein 
completely  by  NaCl  in  substance,  and  then  precipitating  the  globu- 
lins in  the  filtrate  by  magnesium  sulphate  (Sebelien).  The  casein 
may  also  be  precipitated  from  the  diluted  milk  by  acetic  acid  and 
the  globulin  precipitated  after  neutralization  by  means  of  MgSO^. 
In  these  cases  we  obtain  somewhat  high  results,  because  of  the 
presence  of  traces  of  casein  which  remain  behind. 

The  fat  is  gravimetrically  determined  by  thoroughly  extracting 
the  dried  milk  with  ether,  evaporating  the  ether  from  the  extract, 
and  weighing  the  residue.    The  fat  may  be  determined  by  aerometric 
means  by  adding  alkali  to  the  milk,  shaking  with  ether,  and  deter- 
mining the  specific  gravity  of  the  fat  solution  by  means  of  Soxhlet's 
apparatus.     In  determining  the  amount  of  fat  in  a  large  number  of 
'  Zeitschr.  f.  physioL  Chem.,  Bd.  13. 
*  Hoppe-Seyler,  Med.  chem.   Untersucb.,  Heft  3. 
»L.  c. 


432  MILE. 

samples  the  lactocrit  of  De  Laval  may  be  used  with  success.  The 
milk  is  first  mixed  with  an  equal  Yolame  of  a  mixture  of  glacial 
acetic  acid  and  concentrated  sulphuric  acid,  warmed  7-8  minutes  on 
the  water-bath,  the  mixture  placed  in  graduated  tubes,  and  these  in 
the  centrifugal  machine  at  +  50°  C.  The  height  of  the  layer  of 
fat  gives  its  quantity.  The  numerous  and  very  exact  analyses  of 
NiLSON  *  have  shown  that  with  milks  containing  small  quantities 
of  fat,  below  1.5^,  the  older  corrections  are  unnecessary,  and  that 
this  method  gives  excellent  results  if  we  use  lactic  acid  treated  with 
o</o  hydrochloric  acid  instead  of  the  above  mixture  of  glacial  acetic 
acid  and  sulphuric  acid. 

In  determining  the  milk-sugar  first  the  proteids  are  removed. 
For  this  purpose  we  precipitate  either  with  alcohol,  which  must  be 
evaporated  from  the  filtrate,  or  by  diluting  with  water,  and  remov- 
ing the  casein  by  the  addition  of  a  little  acid,  and  the  lactalbumin  by 
coagulation  at  boiling  heat.  The  sugar  is  determined  by  titration 
with  Fehling's  or  Knapp's  solution  (see  Chap.  XV).  The  prin- 
ciple of  titration  is  the  same  as  for  the  titration  of  sugar  in  urine: 
10  c.  c.  of  Fehling's  solution  corresponds  to  0.0676  grm.  milk- 
sugar;  10  c.  c.  of  Knapp's  solution  corresponds  to  0.0311-0.0310 
grm.  milk-sugar,  when  the  saccharine  liquid  contains  about  i-1^ 
sugar.  In  regard  to  the  modus  operandi  of  the  titration  we  must 
refer  the  reader  to  more  complete  works  and  to  Chapter  XV. 

Instead  of  the  volumetric  determinations  the  following  steps 
may  be  taken:  A  measured  quantity  of  the  milk-sugar  solution  is 
treated  with  an  excess  of  Fehling's  solution,  boiled,  the  copper 
suboxide  filtered  and  reduced  in  a  current  of  hydrogen,  and  the 
metallic  copper  weighed.  Soxhlet  ^  has  given  a  table  which  sim- 
2:)lifies  the  calculations  in  such  cases. 

The  sugar  may  also  be  determined  by  the  polariscope,  and  with 
ease,  because  the  filtrates  containing  milk-sugar  are  generally  color- 
less. The  determination  is  qnickly  performed,  but  does  not  give 
exact  results. 

The  quantitative  composition  of  caw's  milk  is  naturally  very 
variable.  The  average  obtained  by  KoisriG  '  is  as  follows  in  1000 
parts: 

Water.  Solids.  Casein.  Albumin.  Fats.  Sugar.  Salts. 

871.7  128.3  30.3  o.3  36.9  48.8  7.1 


35.5 

The  quantity  of  mineral  bodies  in  1000  parts  of  cow's  milk  is, 
according  to  the  analyses  of  Soldner,^  as  follows:  K,0  1.72,  Na,0 

>  Maly's  Jabresber.,  Bd.  21,  S.  142. 

'  Journal  f.  prakt,  Cbem.,  1880. 

^  Cbemle  der  menscbicben  Nabrungs-  und  Qenussmittel,  3.  Aufl. 

*L.  c. 


COLOSTRUM.  433 

0.51,  CaO  1.98,  MgO  0.20,  P,0,  1.82  (after  correction  for  the 
pseudoiiucleiu),  CI  0.98  grms.  Bunge  '  found  0.0035  grm.  Fe^O,. 
According  to  Soldner,  the  K,  Na,  and  CI  are  found  in  the  same 
quantities  in  whole  milk  as  in  milk-serum.  Of  the  total  phosphoric 
acid  36-56^  is  not  simply  dissolved  and  also  53-72^  of  the  lime. 
A  part  of  this  lime  is  combined  with  the  casein;  the  remainder  is 
found  ^^nited  with  the  phosphoric  acid  as  a  mixture  of  di-  and  tri- 
calcium  pohsphate,  which  is  kept  dissolved  or  suspended  by  the 
casein.  The  bases  are  in  excess  of  the  mineral  acids  in  the  milk- 
serum.  The  excess  of  the  first  is  combined  with  organic  acids, 
which  correspond  to  2.5  p.  m.  citric  acid  (Soldner^). 

The  gases  of  the  milk  consist  chiefly  of  CO^,  besides  a  little  N 
and  traces  of  0.  Pfluger'  found  10  vols,  per  cent  CO,  and  0.6 
vol.  per  cent  N,  calculated  at  0°  C.  and  760  mm.  pressure. 

The  variation  in  the  composition  of  cow's  milk  depends  on 
several  circumstances. 

The  colostrum,  or  the  milk  which  is  secreted  before  calving  and 
in  the  first  few  days  after,  is  yellowish,  sometimes  alkaline,  but 
often  acid,  of  higher  specific  gravity,  1.046-1.080,  and  richer  in 
solids  than  ordinary  milk.  The  colostrum  contains,  besides  fat- 
globules,  an  abundance  of  colostrum-corpuscles — nucleated  granular 
cells  0.005-0.025  mm.  in  diameter  with  abundant  fat-grannies  and 
fat-globules.  The  fat  of  colostrum  has  a  somewhat  higher  melting- 
point  and  is  poorer  in  volatile  fatty  acids  than  the  fat  from  ordinary 
milk  (NiLSON*)"  The  quantity  of  cholesterin  and  lecithin  is 
generally  greater.  The  most  apparent  difference  between  it  and 
ordinary  milk  is  that  colostrum  coagulates  on  heating  to  boiling 
because  of  the  absolute  and  relatively  greater  quantities  of  globulin 
and  albumin  it  contains.  The  quantity  of  the  first  of  these  twa 
albuminous  bodies  may  indeed  amount  to  several  per  cent  (Sebe- 
LiEN"  ^).  The  composition  of  colostrum  is  very  variable.  KoNiG  * 
gives  as  average  the  following  figures  in  1000  parts: 

Water.     Solids.     Casein.     Albumin  and  Globulin.     Fat.     Sugar.     Salts. 
746.7       253.3        40.4  136.0  35.9      26.7        15.6 

The  constitution  of  milk  is  changed  during  lactation,  and  it 

'  Zeitschr.  f.  Biologie,  Bd.  10. 

*  L   c. 

a  Pfluger's  Arch.,  Bd.  2. 

*  Maly'.s  Jabresber.,  Bd.  17,  S.  169. 
^  Ibid.,  Bd.  18.  S.  102. 

«  L.  .-. 


434  MILE. 

becomes  riclier  in  casein  but  poorer  in  fat  and  milk-sugar.  The 
evening  milk  is  richer  in  fat  than  the  morning  milk  (Alex.  Muller 
and  EiSEifSTUCK;  Xilson  and  others').  The  breed  of  the  animal 
also  has  a  great  influence  on  the  milk. 

The  influence  food  exercises  upon  the  composition  of  milk  will 
be  discussed  in  connection  with  the  chemistry  of  the  milk  secretion. 

In  tLe  following  we  give  tlie  average  composition  of  skimmed  milk  and 
certain  other  preparations  of  milk : 

Water.  Proteids.         Fat.  Sugar.    Lactic  Acid.    Salts. 

Skimmed  milk.   906.6  31.1  7.4  47.5  ....  7.4 

Cream 655.1  36.1        267.5  35.2  ....  6.1 

Buttermilk....   902.7  40.8  9.3  37.3  3.4  6.7 

\Yliey 982.4  8.5  2.3  47.0  3.3  6.5 

KuMTSS  and  kephie  are  obtained,  as  above  stated,  by  the  alcoliolic  and 
lactic-acid  fermentation  of  the  milk-sugar,  the  first  fmrn  mare's  milk  and  the 
last  from  cow's  milk.  Large  quantities  of  carbon  dioxide  are  formed  thereby, 
and  also  the  albuminous  bodies  of  the  milk  are  partly  converted  into  albumoses 
and  peptones,  which  increases  the  ditrnstibility.  The  quantity  of  lactic  acid 
in  these  preparations  may  be  about  10-20  p.  m.  The  quantity  of  alcohol  varies 
from  10  to  3o  p.  in. 

Milk  from  other  Animals.  Goat's  milk  has  a  more  yellowish  color  and 
another,  more  s^Decific,  odor  than  cow's  milk.  The  coagulation  obtained  by 
acid  or  rennet  is  more  solid  and  is  harder  than  that  from  cow's  milk.  Sheep's 
milk  is  similar  to  goat's  milk,  but  has  a  higher  specific  gravity  and  contains  a 
greater  amount  of  solids. 

Mare's  milk  is  alkaline  and  contains  a  casein  which  is  not  precipitated  by 
acids  in  lumps  or  solid  masses,  but,  like  the  casein  from  woman's  milk,  in  fine 
flakes.  This  casein  is  only  incompletely  precipitated  by  rennet,  and  it  is  very 
similar  also  in  oth^r  respects  to  the  casein  of  human  milk.  According  to  BeiIj,  * 
the  casein  from  mare's  and  cow's  milk  is  the  same,  and  the  different  behavior 
of  the  two  varieties  of  milk  is  due  to  different  amounts  of  salts  and  to  a  differ- 
ent relation  between  the  casein  and  the  albumin.  The  milk  of  the  ass  is  sim- 
ilar to  human  milk. 

The  milk  of  carnivora,  the  bitch  and  cat,  are  acid  in  reaction  and  very  rich 
in  solids.  The  composition  of  the  milk  of  these  animals  varies  very  much  with 
the  composition  oi  the  food. 

To  illu.strate  the  composition  of  the  milk  of  other  animals  the  following 
figures,  the  compilation  of  KoNiG,  will  be  given.  As  the  milk  of  each  variety 
of  animals  may  have  a  variable  comjjosition,  these  figures  may  only  be  con- 
sidered as  examples  of  the  composition  of  milk  of  different  kinds. 

Milk  of  the     Water.  Solids.  Pi-oteids.  Fat.  Sugar.  Salts. 

Dog 754  4  24.-).6  99.1  95.7  31.9  7.3 

Cat 816.3  183.7  9iJ.8  33.3  49.1  5  8 

Gat 869.1  130.9  36  9  40.9  44.5  8.6 

Sheep mn.O  165  0  57  4  61.4  39  6  6.6 

Cow    871.7  128.3  35  5  36.9  48  8  7.1 

Horse 900  6  99.4  18  9  10  9  66.5  31 

Ass   900.0  100.0  21.0  13.0  63.0  3.0 

Pig 823.7  167.3  60.9  64  4  40  4  10  6 

Elephant..  678.5  331.5  30.9  195.7  88.4  6.5 

Dolphin ^.  468.7  513.3             437.5  4.6 

'  See  Konig,  1.  c,  Bd.  1,  S.  313,  and  Nilson,  1.  c. 

'  Studien  iiber  die  Eiweissstoffe  des  Kumys  und  Kefir.  St.  Petersburg, 
1886.     (Ricker.) 

'"  Frankland,  Chem.  News,   1890,  vol.  61. 


HUMAN  MILK.  435 


Human  Milk. 

Woman's  milk  is  amphoteric  in  reaction.  According  to 
OoURANT '  its  reaction  is  relatively  stronger  alkaline  than  cow's 
milk,  but  has  nevertheless  a  lower  absolute  reaction  for  alkalinity  as 
well  as  acidity.  Courant  found  between  the  tenth  day  and  four- 
teenth month  after  confinement  rather  constant  results.  The  alka- 
linity as  well  as  the  acidity  were  a  little  lower  than  in  childbed. 
100  c.  c.  of  the  milk  liad  the  same  average  alkalinity  as  10.8  c.  c. 

— -  caustic  soda  and  the  same  acidity  as  3.6  c.   c.  -—  acid.     The 
10  *^  10 

relationship  between  the  alkalinity  and  acidity  was   for  woman's 

milk  as  3  :  1,  and  in  cow's  milk  as  2.1  :  1. 

Human  milk  also  contains  fewer  fat-globules  than  cow's  milk, 
but  they  are  larger  in  size.  The  specific  gravity  of  woman's  milk 
varies  between  1026  and  1036,  generally  between  1028  and  1034. 
According  to  Monti  ^  the  specific  gravity  of  the  milk  from  healthy, 
robust  women  is  1030-1035.  The  specific  gravity  is  highest  in 
well-fed  and  lowest  in  poorly  fed  women. 

The  fat  of  woman's  milk  has  been  investigated  by  Ruppel.'  It 
forms  a  yellowish,  white  mass,  similar  to  ordinary  butter,  having  a 
specific  gravity  of  0.966  at  -|-  15°  C.  It  melts  at  34.0°  and  solidifies 
at  20.2°  C.  The  following  fatty  acids  can  be  obtained  from  the 
fat,  namely,  butyric,  caproic,  capric,  myristic,  palmitic,  stearic, 
and  oleic  acids.  The  fat  from  woman's  milk  is,  according  to 
RUPPEL,  relatively  poor  in  volatile  fatty  acids.  Laves  *  found  only 
traces  of  butyric  acid  in  tlie  fat  from  woman's  milk.  The  melting- 
point  of  the  fat  was  30-31°  and  of  the  free  fatty  acids  37-39°  C. 
The  non-volatile  fatty  acids  consist  of  one-half  oleic  acid,  while 
among  the  solid  fatty  acids  myristic  and  palmitic  acids  are  found 
to  a  greater  extent  than  stearic  acid. 

The  essential  qualitative  difference  between  woman's  and  cow's 
milk  seems  to  lie  in  the  proteids  or  in  the  more  accurately  deter- 
mined casein.    A  number  of  older  and  younger  investigators'  claim 

'  Ueber  die  Reaktion  der  Kub-  und  Frauenmilch,  etc.     Inaug.   Diss.  Bonn, 
1891;  also  Pfliiger's  Arch.,  Bd.  50. 
'  Arch.  f.  Kinderheilkunde,  Bd.  13. 
»  Zeitsch.  f.  Biologie,  Bd.  31. 
*  Zeitschr.  f.  physiol.  Chem.,  Bd.  19. 
'  See    Biedert,    Untersuchungen    iiber    die   chemischen  Unterschiede   der 


436  MILK. 

that  the  casein  from  woman's  milk  has  other  properties  than  that 
from  cow's  milk.  The  essential  differences  are  the  following :  The 
casein  from  woman's  milk  is  precipitated  with  greater  difficulty 
with  acids  or  salts;  it  does  not  coagulate  regularly  in  the  milk  after 
the  addition  of  rennet;  it  may  be  precipitated  by  gastric  juice,  but 
dissolves  completely  and  easily  in  an  excess  of  the  same;  the  casein 
precipitate  produced  by  an  acid  is  more  easily  soluble  in  an  excess 
of  the  acid;  and  lastly,  the  clot  formed  from  the  casein  of  womL.n'.s 
milk  does  not  appear  in  such  large  and  coarse  masses  as  the  casein 
from  cow's  milk,  but  is  more  loose"  and  flocculent.  This  last-men- 
tioned fact  is  of  great  importance,  since  it  explains  the  generally 
admitted  easy  digestibility  of  the  casein  from  woman's  milk.  The 
question  as  to  whether  the  above-mentioned  differences  depend  on 
a  decided  difference  in  the  two  caseins  or  only  on  an  unequal 
relationship  between  the  casein  and  the  salts  in  the  two  varieties  of 
milk,  or  uj)on  other  circumstances,  has  been  recently  investigated. 
According  to  Szoi^tagh  '  the  casein  from  human  milk  does  not 
yield  any  pseudonuclein  on  pepsin  digestion  and  hence  it  cannot  be 
a  nucleoalbumin.  Weoblewski  '  has  recently  arrived  at  the  same 
results  and  also  found  that  the  two  caseins  had  a  different  composi- 
tion. He  found  the  following  for  the  composition  of  casein  from 
woman's  milk:  0  52.24,  H  7.32,  N  14.97,  P  0.68,  S  1.117, 
0  23.66^.  Woman's  milk  also  contains  lactalbumin  besides  the 
casein  and  a  protein  substance  which  is  very  rich  in  sulphur  (4.7^) 
and  relatively  poor  in  carbon  (Wroblewski),  The  statements  as 
to  the  occurrence  of  albumoses  and  peptones  are  disputed  as  in 
many  other  cases.  No  positive  proof  as  to  the  occurrence  of  albu- 
moses and  peptones  in  fresh  milk  has  been  given. 

The  quantitative  composition  of  womaifs  milk  is,  even  after 
those  differences  are  eliminated  which  depend  on  the  imperfect 
analytical  methods  employed,  variable  to  such  an  extent  that  it  is 
impossible  to  give  any  average  results.  Eliminating  certain  of  the 
older,  incorrect  analyses,  we  here  give  only  examples  from  the 
average  results  of  a  few  modern  investigators,  taken  from  a  very 
large  number  of  analyses  (Pfeiffer).  The  following  figures  are 
parts  per  1000: 

Menschen-  und  Kubmilcli.  Stuttgart,  1884.  Langgaard,  Vircliow's  Arch.,  Bd. 
65.  Makris,  Studien  iiber  die  Eiweisskorper  der  Frauen-  und  Kubmilcli. 
Inaug.  Diss.  Strassburg,  1876. 

'  Maly's  Jabresber.,  Bd.  22,  S.  168. 

^  Beitrage  zur  Kenntniss  des  Frauenkaseins.     Inaug. -Diss.     Bern,  1894. 


COMPOSITION  OF  HUMAN  MILK. 


437 


Water. 

Solids. 

Proteids. 

Fat. 

Clioles- 
teriii. 

Sugar. 

Salts. 

876.0 

124.0 

22.10 
23  60 
17.90 
19  00 
16.18 
17.24 
25.30 

38.10 
25.60 
33.00 
43.20 
32.28 
29.15 
38.90 

6!32* 

60.90 
55.60 
53.90 
59.70 
57.94 
59.92 
55.40 

2.90 

'4.26 
2.80 
1.65 
2.09 
2.50 

BlEL  1 
TOLMATSCHEFF  * 

891.0 

872.4 
892.0 
890.6 
877.9 

109.0 
127.6 
108.0 
109.4 
122.1 

Gejiber  ^ 
Christenn  * 
20-30yrs.old  \  pp„,„p™5 

30-40     "     "     ^i^FEIFPER 

Mendes  de  Leon  « 

Although  the  composition  of  woman's  milk  is  very  variable,  and 
notwithstanding  that  in  a  few  cases  higher  resalts  (about  40  p.  m.) 
have  been  obtained,  by  later  analyses,  for  proteid  bodies,  still  it 
seems  that  woman's  milk  in  general  contains  less  proteids  and  more 
sugar  than  cow's  milk.  The  quantity  of  casein  is  not  only  abso- 
lutely bat  also  relatively  smaller  in  proportion  to  the  quantity  of 
albumin  in  woman's  than  in  cow's  milk.  According  to  Scheibe  ^ 
the  quantity  of  citric  acid  is  smaller  in  woman's  milk  than  in  cow's 
milk. 

A  further  difference  between  woman's  and  cow's  milk  is  that 
the  first  is  richer  in  lecithin  but  poorer  in  mineral  bodies,  especially 
CaO  and  ^fi^  (it  contains  only  \  and  \,  respectively,  of  the  corre- 
sponding quantity  of  these  mineral  bodies  in  cow's  milk). 

In  regard  to  the  quantity  of  mineral  bodies  in  woman's  milk  the 
analyses  of  Bunge  '  are  most  reliable.  He  analyzed  the  milk  of  a 
woman,  fourteen  days  after  delivery,  whose  diet  contained  very 
little  common  salt  for  four  days  previous  to  the  analysis  (A),  and 
again  three  days  later  after  a  daily  addition  of  30  grms.  JSTaCl  to 
the  food  (B).  Bukge  found  the  following  figures  in  1000  parts  of 
the  milk : 

A  B 

KjO 0.780  0.703 

NaaO 0232  0.257 

CaO 0.328  0  343 

MuO 0.064  0.065 

Fe,03 0.004  0006 

P.Os 0.473  0.469 

CI 0.438  0.445 

'  Maly's  Jaliresber.,  Bd.  4,  S.  168. 

*  Hoppe-Seyler,  Med.  chem.  Untersuch.,  Heft  2. 

*  Ball,  de  la  soc.  cliim.,  Tome  23. 
<  Maly's  Jahresber..  Bd.  7,  S.  171. 

*  Jahrb.  f.  Kinderheilkunde,  Bd.  20;  also  Maly's  Jaliresber,,  Bd.  13. 

*  Ueber  die  Zusammecsetzung  der  Frauenmilch.     Inaug.   Diss,  der  Univ. 
Heidelberg,  1881;  also  Maly's  Jaliresber.,  Bd.  12. 

■■  Landwirtliscb.  Versuchsstat.,  Bd.  39. 
«  Zeilscbr.  f.  Biologie,  Bd.  10. 


438 


MILE. 


The  relationship  of  the  two  bodies,  potassium  and  sodium,  to 
each  other  may,  according  to  Bunge,  vary  considerably  (1.3-4.4 
equivalents  potash  to  1  of  soda).  By  the  addition  of  salb  to  the 
food  the  quantity  of  sodium  and  chlorine  in  the  milk  increases, 
while  the  quantity  of  potassium  decreases.  The  gases  of  woman's 
milk  have  been  investigated  by  Kijlz.'  He  found  1.07-1.44  c.  c. 
oxygen,  2.35-2.87  c.  c.  carbon  dioxide,  and  3.37-3.81  c.  c.  nitrogen 
in  100  c.  c.  milk. 

The  proper  treatment  of  cow's  milk  by  diluting  with  water  and 
by  certain  additions  in  order  to  render  it  a  proper  substitute  for 
woman's  milk  in  the  nourishment  of  babes  cannot  be  determined 
before  the  difference  in  the  albuminous  bodies  of  these  two  kinds  of 
milk  has  been  completely  studied. 

Tl^e  colostrum  has  a  higher  specific  gravity,  1.040-1.060,  a 
greater  quantity  of  coagulable  proteids,  and  a  deeper  yellow  color 
than  ordinary  woman's  milk.  Even  a  few  days  after  delivery  the 
color  becomes  less  yellow,  the  quantity  of  albumin  less,  and  the 
number  of  colostrum-corpuscles  diminishes,  Clemm  ^  has  analyzed 
the  colostrum  at  different  periods  before  and  after  delivery,  and  the 
following  are  his  results  in  parts  per  1000 : 


Four  Weeks  before 
Delivery. 

Seventeen 
Days 
lipfore 

Delivery. 

Nine  Days 

before 
Delivery. 

Tweuty- 
Cour  Hours 

after 
Delivery. 

Two  Days 
after 

1 

0 

Delivery. 

Water  . 

Solids 

945.2 

54.8 

852.0 
148.0 

851.7 
148.3 

858.5 
141.5 

843.0 
157.0 

867.9 
132.1 

21.8 

Albuinin 

28.8 
7.1 

17.3 
4.4 

69.0 

41.3 

39.5 

4.4 

74.8 

30.2 

43.7 

4.5 

80.7 

23.5 

36.4 

5.4 

"'s.i' 

Fat 

48.6 

Milk-sugar 

Salts 

61.0 

The  total  quantity  of  proteids  seems  to  decrease  with  the  dura- 
tion of  lactation.  Pfeiffer'  found  the  average  figures  for  the 
total  proteids  for  the  two  first  days,  the  first  week,  the  second  week, 
the  second  month,  and  the  seventh  month  to  be  86.04,  34.42, 
22.88,  18.43,  and  15.21  p.  m.,  respectively.  SiMOisr*  claims  that 
the  amount  of  casein  is  smaller  in  the  first  stages  of  lactation  and 

'  Zeitschr.  f.  Biologie,  Bd.  32. 

'  Cited  from  Hoppe-Seyler's  Physiol.  Chem.,  p.  734. 

3L.  c. 

*  Die  Frauenmilch.     Berlin,  1888. 


HUMAN  COLOSTRUM.  439 

then  increases  considerably;  but  according  to  Pfeiffer  just  the 
reverse  takes  j)lace.  The  amount  of  fat  shows  no  regular  and  con- 
stant variation  during  lactation.  According  to  Vernois  and 
Becquerel  '  the  quantity  of  milk-sugar  decreases  in  the  first 
months,  but  increases  iti  the  eighth  to  the  tenth  month.  Accord- 
ing to  Pfeiffer  the  quantity  of  sugar  increases  regularly  from  the 
delivery  to  the  third  to  fourth  month,  and  then  it  is  somewhat 
variable. 

The  two  mammary  glands  of  the  same  woman  may  yield  somewhat  different 
milk,  as  shown  by  Soukdat  ^  and  later  by  Brunner.*  Also  the  different  por- 
tions of  milk  from  the  same  milking  may  have  different  compositions.  The 
first  portions  are  always  poorer  in  fat. 

According  to  L'tlERiTiKR/  Vernois,  and  Becquerel  the  milk  of  blonds 
contains  less  casein  than  that  of  brunettes,  a  difference  which  Toi.matscheff  * 
could  not  substantiate.  Women  of  weak  constitutions  yield  a  milk  richer  m 
solids,  especially  in  casein,  than  women  with  strong  constitutions  (V.  and  B.). 

According  to  Vernois  and  Becquerel,  the  age  of  the  woman  has  an  effect 
on  the  composition  of  the  milk,  so  that  we  find  a  greater  quantity  of  proteids 
and  fat  in  women  15-20  years  old  and  a  smaller  quantity  of  sugar.  The  small- 
est quantity  of  proteids  and  the  greatest  quantity  of  sugar  are  found  at  20  or 
from  25-30  years  of  age.  According  to  V.  and  B.,  the  milk  with  the  first-born 
is  richer  in  water — with  a  proportionate  diminution  of  the  quantity  of  casein, 
sugar,  and  fat — than  after  several  deliveries. 

The  influence  of  menstruation  seems  to  slightly  diminish  the  milk-sugar 
and  to  considerably  increase  the  fat  and  casein  (V.  and  B.). 

Witch's  Milk  is  the  secretion  of  the  mammary  glands  of  new-born  children 
of  both  sexes  immediately  after  l^irth.  This  secretion  has  from  a  qualitative 
standpoiiat  the  same  constitution  as  milk,  but  may  show  important  differences 
and  variations  from  a  quantitative  point  of  view.  Schlossberger  and 
Haupf,*  GuBLER  and  Quevenne,''  and  v.  Genser^  have  made  analyses  of 
this  milk  and  give  the  following  results  :  10.5-38  p.  m.  proteids,  8  2-14.6  p.  m. 
fat,  and  9-60  p.  m.  sugar. 

As  milk  is  the  only  form  of  nourishment  during  a  certain  period 
of  the  life  of  man  and  mammals,  it  must  contain  all  the  nutritious 
bodies  necessary  for  life.  This  fact  is  shown  by  the  milk-contain- 
ing representatives  of  the  three  chief  groups  of  organic  nutritive 
substances,  proteids,  carbohydrates,  and  fat ;  and  all  milk  seems  to 
contain  also  some  lecithin.  The  mineral  bodies  in  milk  must  also 
occur  in  proper  proportion,  and  on  this  point  the  observations  of 

'  Compt.  rend..  Tome  36,  and  Vernois  et  Becquerel,  Du  lait  chez  la  femme 
dans  I'etat  de  sante,  etc.     Paris,  1853. 
'  Compt.  rend.,  Tome  71. 
»  Pfliiger's  Arch.,  Bd.  7. 

*  Traite  de  chim.  pathol.  Paris,  1842.  Cited  from  Hoppe-Seyler's  Physiol. 
Chem.,  p.  738. 

*  Hoppe-Seyler,  Med.  chem.  Untersuch.,  S.  272. 
«  Annal.  de  Chem.  u.  Pharm.,  Bd   96. 

'  Gaz.  med.  de  Paris,  1856   p.  15. 

«  Jahrb.  f.  Kinderheilkunde,  N.  F.,  Bd.  9,  S.  60. 


440  MILE. 

BuKGE  on  dogs  are  of  special  interest.  He  found  that  the  mineral 
bodies  of  the  milk  occur  in  about  the  same  relative  proportion  as 
they  do  in  the  body  of  the  sucking  animal.  Bunge  '  found  in 
1000  parts  of  the  ash  the  following  results  (A  represents  results 
irom  the  new-born  dog  and  B  the  milk  from  the  bitch) : 

A  B 

KjO 114  3  149.8 

Na^O 106.4  88.0 

CaO 395.2  373.4 

MgO 18.3  15.4 

Fe^Os 7.3  1.3 

PjOs 394.3  343.3 

CI 83.5  169.0 

BuifGE  explains  the  fact  that  the  milk-ash  is  richer  in  potash 
,and  poorer  in  soda  than  the  new-born  animal  by  saying  that  in  the 
.growing  animal  the  ash  of  the  muscles  rich  in  potash  relatively 
Increases  and  the  cartilage  rich  in  soda  relatively  decreases.  Buxge 
;seeks  to  explain  the  high  amount  of  chlorine  in  the  milk-ash  also 
ideologically  by  the  statement  that  the  chlorides  not  only  serve  to 
iDuild  up  the  tissues,  but  are  indispensable  in  the  secretions  of  the 
kidneys.  In  regard  to  the  amount  of  iron  we  find  an  unexpected 
condition,  the  ash  of  the  new-born  animal  containing  six  times  as 
much  as  the  milk-ash.  This  condition  Bui^ge  explains  by  the  fact 
founded  on  his  and  Zalesky's  experiments,  that  the  quantity  of 
iron  in  the  total  organism  is  highest  at  birth.  The  new-born 
animal  has  therefore  a  supply  of  iron  for  the  growth  of  its  organs 
even  at  its  birth. 

The  influence  of  the  food  on  the  composition  of  the  milk  is  of 
interest  from  many  points  of  view  and  has  been  the  subject  of  many 
investigations.  From  these  investigations  we  learn  that  in  human 
beings  as  well  as  in  animals  an  insufficient  diet  decreases  the 
quantity  of  milk  and  tlie  quantity  of  solids  in  the  same,  while 
abundant  food  increases  both.  From  the  observations  of  Decaisne  ' 
on  nursing  women  during  the  siege  of  Paris  in  1871,  the  quantity 
of  casein,  fat,  sugar,  and  salts,  but  especially  the  fat,  was  found  to 
decrease  with  insufficient  food,  while  the  quantity  of  lactalbumin 
was  found  to  be  somewhat  increased.  Food  rich  in  proteids 
increases  the  quantity  of  milk,  and  also  the  solids  contained,  espe- 
cially the  fat.  The  quantity  of  sugar  in  woman's  .milk  is  found  by 
certain  investigators  to  be  increased  after  food  rich  in  proteids, 

'  Zeitschr.  f.  pliysiol.  Che!!i.,  Bd.  18. 

«  Gaz.  med.  de  Paris,  1871,  S.  317  ;  cited  from  Hoppe-Seyler,  1.  c,  S.  739. 


aiEMismr  of  the  milk  secretion.  441 

while  others  claim  it  is  diminished.  Food  rich  in  fat  may  (in 
sheep)  cause  an  increase  in  the  quantity  of  fat  in  the  milk.  An 
increase  in  the  quantity  of  fat  in  cow's  milk  because  of  an  addition 
of  fat  to  the  fodder  has  only  been  observed  after  a  previous  insuffi- 
cient diet,  but  not  after  a  sufficient  and  rich  diet.  After  feeding 
with  palm-oil  cake  a  one-sided  increase  in  the  fat  of  cow's  milk  was 
observed.  The  presence  of  large  quantities  of  carbohydrates  in  the 
food  seems  to  cause  no  constant,  direct  action  on  the  quantity  of 
the  milk-constituents.'  In  carnivora,  as  shown  by  Ssubotijs",'  the 
secretion  of  milk-sugar  proceeds  uninterruptedly  on  a  diet  consisting 
exclusively  of  lean  meat.  Watery  food  gives  a  milk  containing  an 
excess  of  water  of  little  value.  In  the  milk  from  cows  which  were 
fed  on  distillers'  grains  Commaille'  found  906.5  p.  m.  water,  26.4 
p.  m.  casein,  4.3  p.  m.  albumin,  18.2  p.  m.  fat,  and  33.8  p.  m. 
sugar.     Such  milk  has  a  peculiar  sour,  sharp  after-taste. 

Chemistry  of  the  Milk-secretion .  That  the  actually  dissolved 
constituents  occurring  in  milk  pass  into  the  secretion,  not  alone  by 
filtration  or  diffusion,  but  more  likely  are  secreted  by  a  specific 
secretory  activity  of  the  glandular  elements,  is  shown  by  the  fact 
that  milk-sugar,  which  is  not  found  in  the  blood,  is  to  all  appear- 
ances formed  in  the  glands  themselves.  A  further  proof  lies  in  the 
fact  that  the  lactalbumin  is  not  identical  with  seralbumin;  and 
lastly,  as  Buxge  *  has  shown,  the  mineral  bodies  secreted  by  the 
milk  are  in  quite  different  proportions  from  those  in  the  blood- 
serum. 

Little  is  known  in  regard  to  the  formation  and  secretion  of  the 
specific  constituents  of  milk.  The  older  theory,  that  the  casein  was 
produced  from  the  lactalbumin  by  the  action  of  an  enzyme,  is 
incorrect  and  originated  probably  from  mistaking  an  alkali-albumi- 
nate  for  casein.  Better  founded  is  the  statement  that  the  casein 
originates  from  the  protoplasm  of  the  gland-cells,  which  seem  to 

'  In  regard  to  the  literature  on  the  action  of  various  foods  on  woman's  milk, 
see  Zalesky,  "  Ueber  die  Einwirkung  der  Nahrung  auf  die  Zusammensetzung 
und  Nahrhaftigkeit  der  Frauenmilch,"  Berlin,  klin.  Wochenschr.,  1888,  which 
also  contains  the  literature  on  the  importance  of  the  food  on  the  composition  of 
other  varieties  of  milk.  In  regard  to  the  extensive  literature  on  the  influence 
of  various  foods  on  the  milk  production  of  animals,  see  Konig,  Chem.  d. 
menschl.  Nahrungs-  und  Geniissmittel,  3.  Aufl.,  Bd.  1,  S.  298. 

'Centralbl.  f.  d.  med.  Wissensch.,  1866,  S.  337. 

»  Cited  from  Konig,  Bd.  3,  S.  235. 

*  Lehrbuch  d.  physiol.  und  pathol.  Chem.,  1.  Aufl.,  S.  98. 


442  MILK. 

consist  of  casein  or  a  substance  related  to  it.  The  j)revionsly  men- 
tioned (page  420)  nucleoproteid  of  the  gland-cells  appears  to  be  re- 
lated to  casein,  and  it  may  possibly  form  its  mother-snbstance.  There 
does  not  seem  to  be  any  doubt  that  the  protoplasm  of  the  cells  takes 
part  in  the  secretion  in  such  a  manner  that  it  becomes  itself  a  con- 
stituent of  the  secretion.  According  to  Heidenhain"/  the  alveoles 
contain  a  simple  layer  of  cells,  which,  in  the  inactive  gland,  are  flat, 
polyhedrons,  and  with  single  nucleus,  while  in  the  active  gland  they 
often  have  several  nuclei,  are  rich  in  proteid,  and  are  high  and 
cylindrical  in  form.  In  the  inner  part  of  the  cell  turned  towards 
the  cavity  of  the  acinus,  single  fat-granules  are  formed  daring  the 
secretion  which  are  broken  off  with  the  edge  of  the  cells.  The 
broken-off  or  destroyed  cell- substance  in  the  secretion  dissolves  in 
the  milk,  filling  the  lumen  of  the  acinus,  while  the  cells  take  up 
natrition  by  their  outer  parts,  and  grow,  and  replace  the  inner 
parts  used  in  the  secretion.  This  reminds  us  of  the  action  of  the 
pancreas-cells  in  the  secretion  of  the  pancreatic  juice.  The  colos- 
truni-corpuscles  are  not,  according  to  HEiDENHAi]sr,  degenerated 
fat-cells,  but  are  contractile  elements  originating  from  the  epithe- 
lium, which  take  up  finely  divided  fat  and  thereby  obtain  their 
quantity  of  fat-globules. 

That  the  milk-fat  is  produced  by  a  formation  of  fat  in  the 
protoplasm,  and  that  the  fat-globules  are  set  free  by  their  destruc- 
tion, is  a  generally  admitted  opinion  which,  however,  does  not 
exclude  the  possibility  that  the  fat  is  in  part  taken  up  by  the  glands 
from  the  blood  and  eliminated  with  its  secretion.  A  formation  of 
fat  from  carbohydrates  in  the  animal  organism  is  at  the  present  day 
considered  as  positively  proved,  and  it  is  also  possible  that  the  milk- 
glands  also  produce  fats  from  the  carbohydrates  brought  to  them 
by  the  blood.  It  is  a  well-known  fact  that  an  animal  gives  off  for 
a  long  time,  daily,  considerably  more  fat  in  the  milk  than  it 
receives  as  food,  and  this  proves  that  at  least  a  part  of  the  fat 
secreted  by  the  milk  is  produced  from  proteids  or  carbohydrates,  or 
perhaps  from  both.  The  question  as  to  how  far  this  fat  is  produced 
directly  in  the  milk-glands,  or  from  other  organs  and  tissues,  and 
broaght  to  the  gland  by  means  of  the  blood,  cannot  be  decided. 

The  origin  of  the  milk-sugar  is  not  known.  Muntz  '  calls 
attention  to  the  fact  that  a  number  of  very  widely  diffused  bodies 

'  Hermann's  Handbucli  d.  Physiol.,  Bd.  5,  Thl.  1,  S.  380. 
'  Compt.  rend.,  Tome  102. 


CUEMISTRY  OF  THE  MILK  SECRETION.  443 

in  the  vegetable  kingdom — vegetable  mncilage,  gums,  pectin  bodies 
— yield  galactose  as  products  of  decomposition,  and  he  believes, 
therefore,  that  the  milk-sugar  may  be  formed  in  herbivora  by  a 
synthesis  from  dextrose  and  galactose.  This  origin  of  milk-sugar 
does  not  answer  for  carnivora,  as  they  produce  milk-sugar  when  fed 
on  food  consisting  entirely  of  lean  meat.  The  observations  of  Bert 
and  Thierfelder  '  that  a  mother-substance  of  the  milk-sugar,  a 
saccharogen,  occurs  in  the  glands  cannot,  as  the  nature  of  this 
mother-substance  is  still  unknown,  give  further  explanation  as  to 
the  formation  of  milk-sugar.  The  question  whether  the  above- 
mentioned  (page  420)  proteid,  which  yields  a  reducing  substance 
when  boiled  with  dilute  acids,  has  anything  to  do  with  the  forma- 
tion of  milk-sugar  cannot  be  answered  until  further  thorough  inves- 
tigations have  been  made  on  this  subject. 

The  passage  of  foreign  substances  into  the  milk  stands  in  close 
connection  with  the  chemical  processes  of  the  milk-secretion. 

It  is  a  well-known  fact  that  milk  acquires  a  foreign  taste  from 
the  food  of  the  animal,  which  is  in  itself  a  proof  that  foreign  bodies 
pass  into  the  milk.  This  fact  becomes  of  special  importance  in 
reference  to  such  injurious  substances  as  may  be  introduced  into  the 
organism  of  the  nursing  child  by  means  of  the  milk. 

Among  these  substances  may  be  mentioned  opium  and  mor- 
phine, which  after  large  doses  pass  into  the  milk  and  act  on  the 
child.  Alcohol  may  also  pass  into  the  milk,  but  not  probably  in 
such  quantities  as  to  have  any  direct  action  on  the  nursing  child. '^ 
Alcohol  is  claimed  to  have  been  detected  in  the  milk  after  feeding 
cows  with  brewer's  grains. 

Among  inorganic  bodies,  iodine,  arsenic,  bismuth,  antimony, 
zinc,  lead,  mercury,  and  iron  have  been  found  in  milk.  In  icterus 
neither  bile-acids  nor  bile-pigments  pass  into  the  milk. 

Under  diseased  conditions  no  constant  change  has  been  found  in  woman's 
milk.  In  isolated  cases  ScHLOSSBERGER,^  JOLY  and  Filhol*  have  observed 
indeed  a  markedly  abnormal  composition,  but  no  positive  conclusion  can  be  de- 
rived therefrom. 

The  changes  in  cow's  milk  in  disease  have  been  little  studied.  In  tubercu- 
losis of  the  udder  Storch  '  found  tubercule  bacilli  in   the  milk,  and  he  also 

'  L.  c. 

'  Klingemann,  Virchow's  Arch.,  Bd.  126. 
»  Annal.  d.  Chem.  u.  Pharm. ,  Bd.  96. 
*  Cited  from  v.  Gorup-Besanez,  Lehrb.,  4.  Aufl.,  S.  438. 
'  See  Bang,  Om  Tuberkulose  i  Koens  Yver  og  om  tuberkulOs  Maik.    Nord. 
med.  Arkiv.,  Bd.  16;  also  Maly's  Jahresber.,  Bd.  14,  S.  170. 


444  MILK. 

found  that  the  milk  became  more  and  more  diluted  during  the  disease  with  a 
serous  liquid  similar  to  blood-serum,  so  that  the  glands  finally,  instead  of 
yielding  milk,  only  gave  blood-serum  or  a  serous  fluid.  HussON  ^  found  the 
milk  from  cows  sick  with  murrain  contained  more  proteids  but  considerably 
less  fat  and  (in  difficult  cases)  less  sugar  than  normal  milk. 

The  milk  may  be  blue  or  red  in  color,  due  to  the  development  of  micro- 
organisms. 

The  formation  of  concrements  in  the  exit-passages  of  the  cow's  udder  are 
often  observed.  They  consist  chiefly  of  calcium  carbonate,  or  of  carbonate  and 
phosphate  with  only  a  small  amount  of  organic  substances. 

»  Compt.  rend.,  Tome  73. 


CHAPTER  XV. 

THE   URINE. 

The  urine  is  the  most  important  excretion  of  the  animal  organ- 
ism; it  is  the  means  of  eliminating  the  nitrogenous  metabolic 
products,  also  the  water  and  the  soluble  mineral  substances;  and  in 
many  cases  it  furnishes  important  data  relative  to  the  metabolism, 
quantitatively  by  its  variation,  and  qualitatively  by  the  appearance 
of  foreign  bodies  in  the  excretion.  Also  in  many  cases  we  are  able 
from  the  chemical  or  morphological  constituents  which  the  urine 
abstracts  from  the  kidneys,  ureters,  bladder,  and  urethra  to  judge  of 
the  condition  of  these  organs;  and  lastly,  urinary  analysis  affords 
an  excellent  means  of  deciding  the  question  how  certain  medicines 
or  other  foreign  substances  introduced  into  the  organism  are 
absorbed  and  chemically  changed.  Urinary  analysis  has  furnished 
very  important  particulars  especially  relative  to  the  last-mentioned 
question  in  regard  to  the  nature  of  the  chemical  processes  taking 
place  within  the  organism,  and  it  is  therefore  not  only  an  important 
aid  in  diagnosis  to  the  physician,  but  it  is  also  of  the  greatest  im- 
portance to  the  toxicologist  and  the  physiological  chemist. 

In  studying  the  secretions  and  excretions  the  relationship  must 
be  sought  between  the  chemical  structure  of  the  secreting  organ  and 
the  chemical  composition  of  its  secreted  products.  Investigations 
with  respect  to  the  kidneys  and  the  urine  have  led  to  very  few 
results  from  this  standpoint.  Although  the  anatomical  relation  of 
the  kidneys  has  been  carefully  studied,  their  chemical  composition 
has  not  been  the  subject  of  thorough  analytical  research.  In  cases 
in  which  a  chemical  investigation  of  the  kidneys  has  been  under- 
taken, it  has  only  been  in  general  on  the  organ  as  such,  and  not  on 
the  different  anatomical  parts.  An  enumeration  of  the  chemical 
constituents  of  the  kidneys  known  at  the  present  time  can,  there- 
fore, only  have  a  secondary  value. 

445 


446  THE   UBINE. 

In  the  kidneys  we  find  albuminous  bodies  of  different  kinds. 
According  to  Halliburton  '  the  kidneys  do  not  contain  any 
albumin,  but  only  glohuliji  and  nucleoalhumin.  The  globulin 
coagulates  at  about  52°  C.  and  the  nucleoalbnmin  at  63°  C.  The 
quantity  of  phosphorus  in  the  latter  is  0,37^.  According  to 
LiEBERMANisr  ^  the  kidneys  contain  lecitlialhumin,  and  he  ascribes 
to  this  body  a  special  importance  in  the  secretion  of  acid  urines, 
namely,  he  claims  that  the  lecithalbumin,  which  acts  like  an  acid, 
decomposes  in  part  the  alkali-salts  of  the  blood-plasma  in  the  cells, 
combining  with  the  alkalies.  Besides  the  above  protein  substances 
and  the  albuminoids  of  the  connective-substance  group,  the  kidneys 
contain  a  body  similar  to  mucin.  The  question  as  to  whether  pure 
mucin  really  exists  in  the  kidneys  has  not  been  decided.  The  body 
similar  to  mucin,  which  is  a  nucleoalhumin,  and  which  gives  no 
reducing  substance  when  boiled  with  acids  (Loistneerg'),  belongs 
chiefly  to  the  papillae,  while  the  cortical  substanco  is  richer  in  a 
non-mucin-like  nucleoalhumin. 

Fat  occurs   only  in  very   small   amounts  in  the  cells  of   the 

tortuous  urinary  passages.     Among  the  extractive  bodies  of  the 

kidneys    we   find   xantM^i   bodies.,   also   urea,  tiric   acid    (traces), 

glycogen,  leiicin,  inosit,  taurin,  and  cystin  (in  ox-kidneys).     The 

quantitative  analyses  of  the  kidneys  thus   far  made  possess  little 

interest.     Oidtmann  ^  found  810.94  p.  m.  water,   179.16  p.  m. 

organic  and  0.99  p.  m.  inorganic  substance  in  the  kidney  of  an  old 

woman. 

The  fluid  collected  under  pathological  conditions,  as  in  hydronephrosis,  is 
thin  with  a  variable  but  generally  low  specific  gravity.  Usually  it  is  straw- 
yellow  or  paler  in  color,  and  sometimes  colorless.  Most  frequently  it  is  clear, 
or  only  faintly  cloudy  from  white  blood-corpuscles  and  epithelium-cells  ;  in  a 
few  cases  it  is  so  ri(  h  in  form-elements  that  it  appears  like  pus.  Proteids 
occur  generally  only  in  small  amounts;  sometimes  it  is  entirely  absent,  and  in 
a  few  rare  cases  the  amount  is  nearly  as  large  as  in  the  blood-serum.  Urea 
occurs  sometimes  in  considerable  amounts  when  the  parenchyma  of  the  kidneys 
is  only  in  part  atrophied ;  in  complete  atrophy  the  urea  may  be  entirely  absent. 

I.  Physical  Properties  of  Urine. 

Consistency,  transparency,  odor,  and  taste  of  urine.  Urine  is 
tinder  physiological  conditions  a  thin  liquid  and  gives,  when  shaken 
with  air,  a  froth  which  quickly  subsides.     Human  urine  or  urine 

'  Journal  of  Physiol.,  Vol.  13,  Suppl. 

*  Pfluger's  Arch.,  Bdd.  50  and  f)4. 

*  See  Maly's  Jahresber  ,  Bd.  20. 

*  Cited  from  v.  Gorup-Besanez,  Lehrb.,  4.  Aufl.,  S.  733. 


PHYSICAL  PROPERTIES  OF   URINE.  447 

frcm  carnivora,  which  is  habitually  acid,  appears  clear  and  trans- 
parent, often  faintly  fluorescent,  immediately  after  voiding.  When 
allowed  to  stand  for  a  little  while  human  urine  shows  a  light  clond 
(nubecula)  which  consists  of  the  so-called  "  mncus  "  and  generally 
also  contains  a  few  epithelium-cells,  mucus-corpuscles,  and  urate- 
granules.  The  presence  of  a  larger  quantity  of  urates  renders  the 
urine  cloudy,  and  a  clay-yellow,  yellowish-brown,  rose-colored,  or 
often  brick-red  precipitate  {^edimentum  lateritium)  settles  on  cool- 
ing because  of  the  greater  insolubility  of  the  urates  at  the  ordinary 
temperature  than  at  the  temperature  of  the  body.  This  cloudiness 
disappears  on  gently  warming.  In  new-born  infants  the  cloudiness 
of  the  urine  during  the  first  4-5  days  is  due  to  epithelium,  mucus- 
corpuscles,  uric  acid,  and  urates.  The  urine  of  herbivora,  which  is 
habitually  neutral  or  alkaline  in  reaction,  is  very  cloudy  on  account 
of  the  carbonates  of  the  alkaline  earths  present.  Human  urine 
may  sometimes  be  alkaline  under  physiological  conditions.  In  this 
case  it  is  made  cloudy  by  the  earthy  phosphates,  and  this  cloudiness 
does  not  disappear  on  warming,  differing  in  this  respect  from  the 
sedimentum  lateritium.  Urine  has  a  salty  and  faintly  bitter  taste 
produced  by  sodium  chloride  and  urea.  The  odor  of  urine  is 
peculiarly  aromatic;  the  bodies  which  produce  this  odor  are 
unknown. 

The  color  of  urine  is  normally  pale  yellow  when  the  si^ecific 
gravity  is  1.020.  The  color  otherwise  depends  on  the  concentration 
of  the  urine  and  varies  from  pale  straw-yellow,  when  the  urine  con- 
tains small  amounts  of  solids,  to  a  dark  reddish  yellow  or  reddish 
brown  in  stronger  concentration.  As  a  rule  the  intensity  of  the 
color  corresponds  to  the  concentration,  but  under  pathological  con- 
ditions exceptions  occur,  and  such  an  exception  is  found  in  diabetic 
urine,  which  contains  a  large  amount  of  solids  and  has  a  high 
specific  gravity  and  a  pale  yellow  color. 

The  reaction  of  urine  depends  essentially  upon  the  composition 
of  the  food.  The  carnivora  void  an  acid,  the  herbivora  a  neutral  or 
alkaline,  urine.  If  a  carnivora  is  put  on  a  vegetable  diet,  its  urine 
may  become  less  acid  or  neutral,  while  the  reverse  occurs  when  an 
herbivora  is  starved,  that  is,  when  it  lives  upon  its  own  flesh,  as 
then  the  urine  voided  is  acid. 

The  urine  of  a  healthy  man  on  a  mixed  diet  has  an  acid  reac- 
tion, and  the  sum  of  the  acid  equivalents  is  greater  than  the  sum  of 
the  base  equivalents.     This  depends  on  the  fact  that  in  the  physi- 


448  THE  URINE. 

©logical  combustion  of  neutral  substances  (proteids  and  others) 
within  the  organism  acids  are  produced,  chiefly  sulphuric  acid,  but 
also  phosphoric  and  organic  acids,  such  as  hippuric,  uric,  and  oxalic 
acid,  also  aromatic  oxyacids  and  others.  From  this  it  follows  that 
the  acid  reaction  is  not  due  to  one  acid  alone.  We  do  not  know  to 
what  extent  any  one  acid  takes  part  in  the  acid  reaction;  but  as  the 
sum  of  the  base  equivalents  is  greater  than,  or  at  least  the  same  as, 
the  sum  of  the  inorganic  acid  equivalents,  the  acid  reaction  must  be 
due  in  greatest  part  to  organic  acids  or  acid  salts.  It  is  generally 
considered  that  the  acid  reaction  of  human  urine  is  caused  by 
double-acid  alkali-phosphate  (monophosphate).  The  quantity  of 
acid-reacting  bodies  or  combinations  eliminated  by  the  urine  in  24 
hours,  when  calculated  as  oxalic  acid  or  hydrochloric  acid,  is 
respectively  2-4  and  1.15-2.3  grms. 

The  composition  of  the  food  is  not  the  only  influence  which 
affects  the  degree  of  acidity  of  human  urine.  For  example,  after 
taking  food,  at  the  beginning  of  digestion,  when  a  larger  amount 
of  gastric  juice  containing  hydrochloric  acid  is  secreted,  the  urine 
may  be  neutral  or  even  alkaline.  The  statements  of  various  inves- 
tigators are  rather  contradictory  in  regard  to  the  time  of  the  appear- 
ance of  the  maximum  and  minimum  of  the  acidity,  which  may  in 
part  be  explained  by  the  different  individuality  and  different  condi- 
tions of  life  of  the  persons  investigated.  It  has  not  infrequently 
been  observed  that  perfectly  healthy  persons  in  the  morning  void  a 
neutral  or  alkaline  urine  which  is  cloudy  from  earthy  phosphates. 
The  effect  of  muscular  activity  on  the  acidity  of  urine  has  not  been 
positively  determined.  According  to  Hoffmank  '  and  Kingstedt  '•' 
muscular  work  raises  the  degree  of  acidity,  but  Aducco  '  claims 
that  it  decreases  it.  Abundant  perspiration  reduces  the  acidity 
(Hoffmann). 

In  man  and  carnivora  it  seems  that  the  degree  of  acidity  of  the 
urine  cannot  be  increased  above  a  certain  point,  even  though 
mineral  acids  or  organic  acids  which  are  burnt  up  with  difficulty 
are  taken  in  large  quantities.  When  the  supply  of  carbonates  of 
the  fixed  alkalies  stored  up  in  the  organism  for  this  purpose  is  not 
sufficient  to  combine  with  the  excess  of  acid,  then  ammonia  is  split 

'  Zur  Semiologie  des  Harns.  Inaug.-Diss.  Berlin,  1884.  See  Maly's  Jah- 
resber.,  Bd.  14,  S,  213. 

s  See  Maly's  Jaliresber. ,  Bd.  20,  S.  196. 
■'  Ibid.,  Bd.  17,  S.  179, 


DETERMINATION  OF  THE  ACIDITY.  449 

from  the  })roteicls  or  their  decomposition  products,  and  tlie  excess 
of  acid  combines  therewith,  formiug  ammonium  salts  which  pass 
into  the  urine.  In  herbivora  this  splitting  of  ammonia  and  forma- 
tion cf  ammonia  salts  does  not  seem  to  take  place,  and  the  herbivora 
therefore  soon  die  when  acids  are  given.  Nevertheless  the  degree 
of  acidity  of  human  urine  may  be  easily  diminished  so  that  the 
reaction  is  neutral  or  alkaline.  This  occurs  after  the  taking  of 
carbonates  of  the  fixed  alkalies  or  of  such  salts  of  vegetable  acids — 
tartaric-acid,  citric-acid,  and  malic-acid  salts — as  are  easily  burnt 
into  carbonates  in  the  organism.  Under  pathological  conditions,  as 
in  the  absorption  of  alkaline  transudations,  the  urine  may  become 
alkaline  (Quincke'). 

The  degree  of  acidity  cannot  be  determined  by  the  ordinary 
acidimetric  process,  since  the  urine  contains  di-hydrogen  phosphate, 
MHjPO^,  besides  hydrogen  di-phosphate,  M^HPO^.  In  the  titration 
the  di-hydrogen  phosphate  is  changed  gradually  into  jMJIPO^,  and 
we  obtain  at  a  certain  point  a  mixture  of  the  two  phosphates  in 
variable  proportions,  which  mixture  is  not  neutral  but  amphoteric. 
Since  it  is  generally  admitted  that  the  acid  reaction  of  urine  is  due 
to  the  di-hydrogen  phosphate,  it  is  therefore  best  to  express  the 
degree  of  acidity  by  the  amount  of  di-hydrogen  phosphate 
present. 

If  we  wish  to  calculate  the  degree  of  acidity  of  the  urine  as 
di-hydrogen  phosphate  or,  still  more  simply,  as  phosphoric  anhy- 
dride, P,Oj_,  contained  in  this  salt,  the  titration  is  performed  accord- 
ing to  the  method  of  Maly  and  Hoffmann,"  which  is  as  follows: 
The  urine  (100-200  c.  c.)  is  treated  with  an  exactly  measured 
quantity  of  ^  normal  caustic-soda  solution,  which  is  more  than  suffi- 
cient to  convert  all  the  phosphate  into  basic  phosphate,  or,  in  other 
words,  enough  to  make  the  urine  strongly  alkaline.  Then  an 
approximate  f  normal  BaCl,  solution  (142.8  grms.  BaCl3,21I„0  in 
a  litre)  is  added  until  no  further  precipitate  is  formed.  By  this 
means  all  the  phosphoric  acid  is  precipitated  from  the  urine.  Filter 
through  a  dry  filter,  measure  a  quantity  corresponding  to  50  or  100 
c.  c.  of  the  original  urine  from  the  filtrate,  and  titrate  with  ^ 
normal  sulphuric  acid  until  a  neutral  reaction  is  obtained,  using 
litmus-paper  as  an  indicator.  If  the  amount  found  by  this  titration 
be  subtracted  from  the  original  amount  of  caustic  soda  added  to  this 
volume  of  urine,  the  difference  is  the  amount  of  caustic  soda  neces- 
sary to  convert  the  existing  di-hydrogen  and  hydrogen  di-phosphates 
into  normal  phospliate.  If  we  designate  this  by  a,  and  the  quantity 
of  total  P,0^  in  milligrammes  in  the  same  quantity  of  urine,  as 

»  Zeitschr.  f.  klin.  Med.,  Bd.  7,  Suppl.,  1884. 

*  Maly,  Zeitschr.    f.   anal.  Cliem.,  Bd.  15,  and  F.  Hoffmann,  Arch.  d.  Heil- 
kunde,  Bd.  17. 


450  THE    URINE. 

determined  by  a  method  which  will  be  described  later,  by  g,  then 
we  obtain  the  quantity  of  P^O^  in  milligrammes  in  the  di-hydrogen 
phosphate  s  by  the  following  formula:  s  =  17.75a  —  g. 

If,  for  example,  in  a  case  in  which  the  conversion  of  both  phos- 
phates into  normal  phosphate  in  100  c.  c.  of  the  urine  required  20 
c.  c.  caustic  soda,  while  the  total  quantity  of  P^O^  in  100  c.  c.  urine 
was  275  milligrammes,  then  s  —  17.75  X  20  —  275  =  80  milli- 
grammes. The  quantity  of  P.,0,  as  simple  acid  phosphate  was 
therefore  195  milligrammes. 

This  method,  according  to  Lieblein','  gives  too  high  figures  for 
the  di-hydrogen  phosphate.  The  quantity  of  alkali  used  is  too 
great  because  of  the  formation  of  basic  barium  phosphate.  Lieb- 
LEiK"  recommends  the  following  method  as  suggested  by  Fkeund." 
Pirst  determine  the  total  quantity  of  phosphoric  acid  in  the  urine 
by  means  of  titration  with  uranium  solution  and  then  precipitate 
the  phosphoric  acid  existing  as  simple  acid  salts  in  another  portion 
by  barium  chloride,  and  determine  the  phosphoric  acid  remaining  in 
a  portion  of  the  filtrate  as  monophosphate  by  titration  with  uranium 
solution. 

According  to  Liebleiist  10  c.  c.  of  a  normal  barium  chloride 
solution  (122  grm.  BaCl,,2H50  in  1  litre)  are  used  to  precipitate 
each  100  milligrammes  total  phosphoric  acid  existing  as  simple  acid 
salts,  the  filtrate  made  up  to  100  c.  c.  and  the  phosphoric  acid 
determined  in  50  c.  c.  thereof.  In  the  precipitation  of  the  urine 
wich  BaClj  about  3^  of  the  phosphoric  acid  existing  as  simple  acid 
salts  remains  in  solution  as  double  acid  salt,  and  hence  a  correspond- 
ing correction  must  be  made.  As  one  third  of  the  phosphoric  acid 
is  combined  with  fixed  bases  as  double  acid  salts,  Lieblein  is  of  the 
opinion  that  in  calculating  the  acidity  of  a  urine  only  two  thirds  of 
this  phosphoric  acid  is  to  be  ascribed  thereto. 

Frexjnd  and  Toepfer  ^  have  lately  suggested  a  method  for  the 
determination    of   the    acidity   as   well   as   the    alkalinity   of    the    urine    by 

means  of  titration  with  —  caustic  soda,  or   —  hydrochloric  acid,  using  phe- 

nolphthalein,  sodium  alizarin  sulphonate,  or  a  solution  of  Poirter's  blue 
as  indicators.  Lieblein's'*  investigations  do  not  speak  in  favor  (rf  this 
method, 

A  urine  with  an  alkaline  reaction  caused  by  fixed  alkalies  has  a 
very  different  diagnostic  value  from  one  whose  alkaline  reaction  is 
caused  by  the  presence  of  ammonium  carbonate.  In  the  latter  case 
we  have  to  deal  Avith  a  decomposition  of  the  urea  of  the  urine  by 
the  action  of  micro-organisms. 

1  Zeitschr.  f.  physiol.  Chem.,  Bd.  20. 

2  Centralbl.  f.  d.  med.  Wissensch.,  1892,  S.  689. 

3  Zeitschr.  f.  physiol.  Chem.,  Bd.  19,  S.  84 
^L.  c. 


SPECIFIC  GRAVITY  OF  URINE.  451 

If  "vre  -wish  to  determine  whether  the  alkaline  reaction  of  the 
nrine  is  due  to  ammonia  or  fixed  alkalies,  we  dip  a  piece  of  red 
litmns-paper  into  the  nrine  and  allow  it  to  dry  exposed  to  the  air  or 
to  a  gentle  heat.  If  the  alkaline  reaction  is  dae  to  ammonia,  the 
paper  becomes  red  again ;  but  if  it  is  caused  by  fixed  alkalies,  it 
remains  blue. 

The  specific  gravity  of  urine,  which  is  dependent  upon  the 
relationship  existing  between  the  quantity  of  water  secreted  and  the 
solid  urinary  constituents,  especially  the  urea  and  sodium  chloride, 
may  vary  considerably,  but  is  generally  1.017-1.020.  After  drink- 
ing large  quantities  of  water  it  may  fall  to  1.002,  while  after  profuse 
perspiration  or  after  drinking  very  little  water  it  may  rise  to  1.035- 
1.040.  In  new-born  infants  the  specific  gravity  is  low,  1.007-1.005. 
The  determination  of  the  specific  gravity  is  an  important  means  of 
learning  the  average  amount  of  solids  eliminated  from  the  organism 
with  the  urine,  and  on  this  account  the  determination  becomes  of 
true  value  only  when  at  the  same  time  the  quantity  of  urine  voided 
in  a  given  time  is  determined.  The  difl'erent  portions  of  urine 
voided  in  the  course  of  the  24  hours  are  collected,  mixed  together, 
the  total  quantity  measured,  and  then  the  specific  gravity  taken. 

The  determination  of  tlie  specific  gravity  is  most  accurately 
obtained  with  the  pyknonieter.  For  ordinary  cases  the  specific 
gravity  may  be  determined  with  sufficieut  accuracy  by  means  of 
areometers.  The  areometers  found  in  the  trade,  or  nrinometers, 
are  graduated  from  1.000  to  1.040;  for  exact  observations  it  is 
better  to  use  two  uriuometers,  one  graduated  from  1.000  to  1.020, 
and  the  other  from  1.020  to  1.040,  A  special  urinometer  is  that 
of  Heller,  which  is  graduated  according  to  Baume's  scale,  from 
0  to  8.  Each  degree  corresponds  to  7  degrees  of  the  ordinary 
urinometer,  and  as  the  zero-point  of  Heller's  urinometer  corre- 
sponds to  the  figure  1000,  then  the  1,  1.5,  2,  2.5,  3,  etc.,  degrees 
of  Heller's  urinometer  correspond  to  1.007,  1.0105,  1.014, 
1.0175,  1.024,  etc.,  of  the  ordinary  specific  gravity. 

To  determine  the  specific  gravity  of  urine,  if  necessary  filter  the 
urine,  or  if  it  contains  a  urate  sediment,  first  dissolve  it  by  gentle 
heat,  then  pour  the  clear  urine  into  a  dry  cylinder,  avoiding  the 
formation  of  froth.  Air-bubbles  or  froth,  Avhen  present,  must  be 
removed  with  a  glass  rod  or  filter-paper.  The  cylinder,  which  must 
be  about  |  full,  must  be  wide  enough  to  allow  the  urinometer  to 
swim  freely  in  the  liquid  without  touching  the  sides.  The  cylinder 
and  urinometer  should  both  be  dry  or  previously  washed  with  the 
nrine.  On  reading,  the  eye  is  brought  on  a  level  with  the  lower 
meniscus — which  occurs  when  the  surface  of  the  liquid  and  the 
lower  limb  of  the  meniscus  coincide;  the  reading  is  then  made  froia 


452  THE    URINE. 

the  point  where  this  curved  line  cuts  the  scale  of  the  nrinometer. 
If  the  eye  is  not  in  the  same  horizontal  plane  with  the  convex  line 
of  the  meniscus,  but  is  too  high  or  too  low,  the  surface  of  the  liquid 
assumes  the  shape  of  an  ellipse,  and  the  reading  in  this  ]3osition  is 
incorrect.  Before  reading  press  the  urinometer  gently  down  into 
the  liquid  and  then  allow  it  to  rise,  and  wait  until  it  is  at  rest. 

If  the  quantity  of  urine  at  disposal  is  not  sufficient  to  fill  the 
cylinder  to  the  proper  height  it  may  be  diluted,  according  to  cir- 
cumstances, with  an  equal  volume  or  several  volumes  of  water. 
This  does  not  give  quite  accurate  results,  and  with  small  quantities 
of  urine  it  is  best  to  determine  the  specific  gravity  by  means  of  the 
pyknometer. 

Each  urinometer  is  graduated  for  a  certain  temperature,  which 
is  marked  on  the  instrument,  or  at  least  on  the  best.  If  the  urine 
is  not  at  the  proper  temperature,  the  following  corrections  must  be 
made:  For  every  three  degrees  above  the  normal  temperature  one 
unit  of  the  last  order  is  added  to  the  reading,  and  for  every  three 
degrees  below  the  normal  temperature  one  unit  (as  above)  is  sub- 
tracted from  the  specific  gravity  observed.  For  example,  when  a 
urinometer  graduated  for  +  15°  C.  shows  a  specific  gravity  of 
1.017  at  +  24°  C,  then  the  specific  gravity  at  -f  15°  C.  =  1.017 
+  0.003  =  1.020. 

II.  Organic  Physiological  Constituents  of  the 

Urine. 

t 
Urea,  Ur,  which  is  ordinarily  considered  as  carbamid,  C0(]SriIj5,, 

may  be  synthetically  prepared  in  several  different  ways,  namely, 

from  carbonyl-chloride,  or  carbonic-acid  ethyl-ether  and  ammonia,^ 

OOCl,  +  2NH3  =  00(NH,),  +  2HC1,  or  (C,HJ,.0,.CO  +  2NH, 

=  2(C^H^.0H) -(- CO(NHJ^;  by  the  metameric  decomposition  of 

ammonium   cyanate,   CO:  N.NII,  =  CO(NHJ,    (Wohler,   1828)  j 

and  in  many  other  ways.     It  is  also  formed  by  the  decomposition 

or  oxidation   of  certain   bodies   found    in    the    animal    organism, 

such  as  creatin  and  uric  acid. 

Urea  is  found  most  abundant  in  the  urine  of  carnivora  and  man,. 

but  in  smaller  quantities  in  that  of  herbivora.     The  quantity  in 

human  urine  is  ordinarily  20-30  p.  m.     It  has  also  been  found  in 

small  quantities  in  the  urine  of  certain    birds   and  amphibians. 

Urea  occurs  in  the  perspiration  in  small  quantities,  and  as  traces  in 

the  blood  and  in  most  of  the  animal  fiuids.    It  also  occurs  in  rather 

large  quantities  in  the  blood,  liver,  muscle  (v,  Schroeder ')  and 

bile"  of  sharks.     Urea  is  also  found  in  certai  n  tissues  and  organs  of 

'  Zeitsclir.  f.  physiol.  Chem.,  Bd.  14. 

'  Investigations  not  published  liy  the  author. 


UREA.  403 

Tiiammals,  especially  in  the  liver  and  spleen,  and  in  smaller  qaaiiLi- 
ties  in  the  muscles.  Under  pathological  conditions,  as  in  obstructed 
excretion,  nrea  may  appear  to  a  considerable  extent  in  the  animal 
fluids  and  tissues. 

The  quantity  of  nrea  which  is  voided  in  24  hours  on  a  mixed 
diet  is  in  a  grown  man  about  30  grms,,  for  women  somewhat  less. 
Ciiildren  void  absolutely  less,  but  relative  to  their  body-weight  the 
excretion  is  larger  than  in  grown  persons.  The  physiological  sig- 
nificance of  urea  lies  in  the  fact  that  this  body  forms  in  man  and 
carnivora,  from  a  quantitative  standpoint,  the  most  important  ni- 
trogenous final  product  of  the  metabolism  of  proteid  bodies.  On 
this  account  the  elimination  of  urea  varies  to  a  great  extent  with 
the  amount  of  proteid  transformed,  and  above  all  with  the  quantity 
of  absorbable  proteids  in  the  food  taken.  The  elimination  of  urea 
is  greatest  after  an  exclusive  meat  diet,  and  lowest,  indeed  less  than 
during  starvation,  after  the  consumption  of  non-nitrogenous  bodies, 
for  these  diminish  the  metabolism  of  the  proteids  of  the  body. 

If  the  consumption  of  the  proteids  of  the  body  is  increased,  then 
the  elimination  of  urea  is  correspondingly  increased.  This  is  found 
to  a  rather  high  degree  in  certain  diseases  with  fever:  also  in  other 
cases  of  increased  elimination  of  nitrogen,  such  as  after  poisoning 
with  arsenic,  antimony,  and  phosphorus,  by  a  diminished  supply  of 
oxygen — as  in  severe  and  continuous  dyspnoea,  poisoning  with 
carbon  monoxide,  hemorrhage,  etc.- — ^it  used  to  be  considered  that 
it  was  due  to  an  increased  elimination  of  urea  because  no  exact 
difference  was  made  between  the  quantity  of  urea  and  the  total 
quantity  of  nitrogen  in  the  urine.  Eecent  researches  have  com- 
pletely demonstrated  the  untrustworthiness  of  these  observations. 
Since  Pfluger  and  Bohland  '  have  shown  that  16^  of  the  total 
nitrogen  of  the  urine  exists  under  physiological  conditions  as  other 
combinations,  not  urea,  attention  has  been  called  to  the  relative 
relationship  of  the  different  nitrogenous  constituents  of  the  urine  to 
each  other,  and  it  has  been  found,  under  pathological  conditions, 
that  this  relationship  may  vary  very  considerably,  especially  in 
regard  to  the  urea.  We  have  numerous  estimations  by  different 
investigators,    sach    as    Bohland,"    E.    Scitultze,"    Camerer,* 

>  Pfluger's  Arcb.,  Bdd.  38  and  43. 

'  Ibid.,  Bd.  43. 

^  Ihid.,  Bd.  45. 

*Zeitschr.  f.  Biologie,  Bdd.  24,  27,  and  28. 


454  THE    URINE. 

VoGES,'  MoRNEE  and  Sjoqvist,"  Gumlich,'  and  others,  on  the 
relationship  of  the  different  nitrogenous  constituents  Lo  eacii  other 
in  normal  urine  of  adults.  Sjoqvist  *  has  made  similar  estimations 
on  new-born  babes  from  1-7  days  old.  From  all  these  analyses  we 
obtain  the  following  figures,  A  for  adults  and  B  for  new-born  babes. 
Of  the  total  nitrogen,  we  have: 

A  B 

Urea 84-91^  73-76 

Ammonia. 2-5  7.8-9.6 

Uric  acid 1-3  3.0-8.5 

Remaining  nitrogenous  substances  (extractives) 7-12  7.3-14.7 

The  different  relationship  between  uric  acid,  ammonia,  and  urea 
nitrogen  in  children  and  adults  is  remarkable,  since  the  urine  of 
children  is  considerably  richer  in  uric  acid  and  ammonia  and  con- 
siderably poorer  in  urea  than  the  urine  of  adults.  In  disease  the 
proportion  of  the  nitrogenous  substances  may  be  markedly  changed 
and  a  decrease  in  the  quantity  of  urea  and  an  increase  in  the  quan- 
tity of  ammonia  have  been  observed  in  certain  diseases  of  the  liver. 
This  will  be  treated  of  in  detail  in  connection  with  the  formation 
of  urea  in  the  liver.  It  is  natural  that  there  is  a  diminished  forma- 
tion of  urea  in  diminished  administration  of  proteids  or  diminished 
consumption  of  proteids.  In  diseases  of  the  kidneys  which  disturb 
or  destroy  the  integrity  of  the  epithelium  of  the  tortuous  urinary 
passage  the  elimination  of  urea  is  considerably  diminished. 

Formation  of  urea  in  the  organism.  The  experiments  to  pro- 
duce urea  directly  from  proteids  by  oxidation  have  not  led  to  any 
positive  results.  On  the  contrary  Drechsel,  as  mentioned  in 
Chapter  II,  has  obtained  lysin  and  lysatin  as  products  of  the 
hydrolytic  cleavage  of  proteids  and  obtained  urea  from  the  lysatin 
by  the  action  of  alkalies.  According  to  Drechsel  and  Hedin"  (see 
Chap.  II,  p.  21,  and  Chap.  IX,  p.  302)  these  two  bodies  are  pro- 
duced by  the  hydrolytic  cleavage  of  proteids  by  trypsin,  and  it  is 
also  possible  that  a  part  of  the  urea  may  be  formed  by  a  hydrolytic 
cleavage  of  proteids  with  these  two  bodies  as  intermediate  steps. 

Creatin  and  creatinin,  which  are  homologues  of  lysatin,  are 
products  of  the  destruction  of  proteid  in  the  animal  body  and  also 

'  Ueber  die  Mischung  der  stickstoffhaltigen  Bestandtheile  im  Harn,  etc. 
Inaug.-Diss.     Berlin,  1892.     Cited  from  Maly's  Jaliresber.,  Bd,  22. 

^  Skand.  Arch.  f.  Physiol.,  Bd.  2.  See  also  Sjoqvist,  Nord.  med.  Arkiv.» 
1892,  No.  86. 

8  Zeitschr.  f .  physiol  Chem,,  Bd.  17. 

■»  Nord.  med.  Arkiv.,  1894,  No.  10. 


FORMATION  OF  UREA.  455 

yield  nrea  by  the  action  of  alkalies,  hence  they  may  be  steps  in  the 
formation  of  urea  in  the  body. 

In  the  decomposition  of  proteid  bodies  we  ordinarily  obtain,  as 
mentioned  in  Chapter  II,  amido-acids  of  various  kinds,  hence  we 
consider  the  amido-acids  as  intermediate  steps  in  the  formation  of 
urea  from  proteids.  It  has  been  shown  that  leucin  and  glycocoll 
(ScHULTZEN  and  Nencki,'  vSalkowski")  and  aspartic  acid 
(v.  Knieeiem')  may  be  in  part  transformed  into  urea  within  the 
organism.  The  nature  of  the  chemical  processes  by  which  these 
transformations  are  effected  is  not  positively  known.  Schmiede- 
BERG  claims  that  the  nitrogenous  combinations  in  which  the 
nitrogen  exists  in  the  group  Nlij-CHj  are  decomposed  in  the 
organism  with  the  formation  of  ammonia,  and  also  that  the  am- 
monium carbonate  is  then  converted  by  a  synthesis  into  urea.  The 
correctness  of  the  last  statement  has  been  recently  confirmed  by 
many  investigators.     Thus  the  researches  of  v.  Knieriem,*  Sal- 

KOWSKI,"    FeDER,''     I.     MUXK,'      CORANDA,'     SCHMIEDEBERG     and 

Fr.  Walter,"  and  Hallerwordex,'"  on  the  behavior  of  ammonium 
salts  in  the  animal  body  and  the  elimination  of  the  ammonia  under 
various  conditions,  have  shown  that  the  ammonium  salts  with  strong 
acids  act  differently  in  the  organism  of  carnivora  and  herbivora, 
while  ammonium  carbonate  or  such  salts  which  are  burnt  into  car- 
bonate in  the  organism  are  transformed  into  urea  by  carnivora  as 
well  as  herbivora.  The  researches  of  v.  Schroder  "  have  given  an 
explanation  as  to  the  organ  in  which  nrea  is  formed.  By  passing 
blood  which  had  been  treated  with  ammonium  carbonate  or  am- 
monium formate  through  a  dog's  liver  he  found  a  very  considerable 
formation  of  urea,  and  these  observations  have  been  confirmed  by 
the  very  careful  observations  of   SALOMO>f."      The  formation  of 

•Zeitschr.  f.  Biologie,  Bd.  8. 

*  Zeitschr.  f.  pliysiol.  Cbem.,  Bd.  4. 
»  Zeitschr.  f.  Biologie,  Bd.  10. 
*Ibid.,  Bd.  10. 

*  Zeitschr.  f.  physiol.  Chem.,  Bd.  1. 

*  Zeitschr.  f .  Biologie,  Bd.  13. 

'  Zeitschr.  f.  physiol.  Chem,,  Bd.  2. 

»  Arch.  f.  Path.  u.  Pharm.,  Bd.  12. 

^  Ibid.,  Bd.  7. 

'"Ibid.,  Bd.  10. 

"  Ibid.,  Bd.  15. 

"  Virchow's  Arch.,  Bd.  97. 


456  THE   URINE. 

urea  from  ammoniam  carbonate  is  to  be  considered  as  a  synthesis 
with  the  expulsion  of  water. 

The  formation  of  urea  from  amido-acids  has  been  explained  in 
other  ways.  Schultzen  and  Nei^cki  '  have  expressed  the  view 
that  the  amido-acids  yield  carbamic  acid  in  the  animal  body,  which 
then  is  transformed  into  urea.  This  view  has  later  received  further 
support  by  more  important  observations.  Drechsel''  has  shown 
that  the  amido-acids  yield  carbamic  acids  by  oxidation  in  alkaline 
flaid  outside  of  the  organism,  and  he  obtained  urea  from  ammonium 
carbamate  by  passing  an  alternate  electric  current  through  its  solu- 
tion, namely,  by  alternate  oxidation  and  reduction.  Drechsel  has 
also  been  able  to  detect  small  quantities  of  carbamates  in  blood,  and 
later  in  conjunction  with  Abel  ^  he  detected  carbamic  acid  in  alka- 
line horse's  urine.  Drechsel  therefore  accepts  the  formation  of 
urea  from  ammonium  carbamate,  and  according  to  him  the  alternat- 
ing oxidation  and  reduction  take  place  in  the  following  way : 

H.N.O.CO.NH, +  0  =H,N.O.CO.NH, +  H,0 
and 

H.KO.CO.NH,  +  H,  =  H.N.OO.NH,  +  H,0. 

Urea. 

Abel  and  Muirhead  '  have  later  observed  an  abundant  elimina- 
tion of  carbamic  acid  in  human  and  dog's  urine  after  the  adminis- 
tration of  large  quantities  of  milk  of  lime,  and  finally  the  regular 
appearance  of  this  acid  in  normal  acid  human  and  dog's  urine  has 
been  made  very  probable  by  M.  Neistcki  and  Hahn^.'  These  last- 
mentioned  investigators  have  also  given  very  important  support  to 
the  theory  of  the  formation  of  urea  from  ammonium  carbamate  by 
observations  on  dogs  with  Eck's  fistula.  In  this  case  the  portal 
vein  is  directly  connected  with  the  inferior  vena  cava,  and  a  com- 
munication is  thus  established  so  that  the  blood  of  the  portal  vein 
flows  directly  into  the  vena  cava,  without  passing  through  the  liver. 
Nencki  and  Hahn  observed  violent  symptoms  of  poisoning  in  dogs 

'  Zeitschr.  f.  Biologie,  Bd.  8. 

'  Ber.  d.  saclis.  Gesellscli.  d.  Wissensch.,  1875.  See  also  Journ.  f.  prakt. 
Chem.  (N.  F.),  Bdd.  12,  16,  and  32. 

»  Du  Bois-Reymond's  Arch.,  1891,   S.  236. 

*  Arch,  f .  exp.  Path.  u.  Pharm. ,  Bd.  31. 

5  Hahn,  Massen,  Nencki  et  Pawlow,  La  fistule  d'Eck  de  la  veins  cave  in- 
ferieur  et  de  la  veine  porte,  etc.  Arch,  des  sciences  biol.  de  St.  Petersbourg, 
Tome  1,  No.  4,  1892;  also  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd   32,  S.  161. 


FORMATION  OF  UREA.  457 

after  this  operation,  and  tliese  symptoms  were  quite  identical  with 
those  obtained  on  introducing  carbamate  into  the  blood.  These 
symjDtoms  also  appear  after  the  introduction  of  carbamate  into  the 
stomach,  while  the  introduction  of  carbamate  into  the  stomach  of  a 
normal  dog  had  no  action.  As  these  observers  also  found  that  the 
urine  of  the  dog  on  which  the  operation  was  made  was  richer  in 
carbamate  than  that  of  the  normal  dog,  they  conclude  that  the 
symptoms  were  due  to  the  non-transformation  of  the  ammonium 
carbamate  into  urea  in  the  liver,  and  they  consider  the  ammonium 
carbamate  as  the  substance  from  which  the  urea  is  derived  in  the 
liver  of  mammals. 

The  view  as  to  the  formation  of  urea  from  ammonium  carbamate 
does  not  contradict  the  above  statement  as  to  the  transformation  of 
carbonates  into  urea,  since  we  can  imagine  that  the  carbonate  is  first 
converted  into  carbamate  with  the  expulsion  of  a  molecule  of  water, 
and  that  this  then  is  transformed  into  urea  with  the  expulsion  of  a 
second  molecule  of  water. 

Besides  the  above-mentioned  theories  as  to  the  formation  of  urea 
we  have  others,  which  will  not  be  given  because  the  only  theory 
which  has  thus  far  been  positively  demonstrated  is  the  formation  of 
urea  from  ammonium  compounds  in  the  liver. 

The  question  in  which  organ  urea  is  formed  has  been  the  subject 
of  numerous  investigations.  From  the  researches  of  numerous 
investigators,  Prevost  and  Dumas,  Meissner,  Voit,  Grehant, 
GscHEiDLEX,  Salkowski,  and  v.  Schroder,'  it  has  been  found 
that  the  extirpation  of  the  kidneys  causes  a  considerable  increase  in 
the  quantity  of  urea  in  the  blood,  and  that  the  kidneys  therefore, 
if  they  produce  urea  at  all,  are  not  the  only  organs  which  can  pro- 
duce it.  By  experiments  performed  on  the  removed  kidneys,  which 
were  analogous  to  the  above-mentioned  experiments  on  the  removed 
liver,  V.  Schroder  has  shown  that  neither  the  kidneys  nor  the 
muscles  nor  the  remaining  tissues  of  the  lower  extremities  of  the 
dog  have  the  property  of  forming  urea  from  ammonium  carbonate. 
The  liver  is  the  only  organ  where  the  formation  of  urea  from 
ammonium  compounds  has  been  j)roved  with  certainty,  and  the 
question  arises  as  to  the  importance  of  these  compounds  to  the  urea 
synthesis  in  the  liver.  Is  all  or  the  chief  mass  of  the  urea  formed 
from  ammonium  compounds  in  the  liver  ? 

'  Arch,  f,  exp.  Path.  u.  Pharin. ,  Bdd.  15  and  19.  In  regard  to  the  ahove- 
citpd  researches  and  the  older  literature  on  this  subject  we  refer  the  reader  to 
V.  Schroder,  and  also  Voit,  Zeitschr.  f,  Biologie,  Bd.  4. 


458  TEE   UBINE. 

No  satisfactory  answer  can  be  given  at  present  to  this  question. 
If  urea  is  formed  from  ammonium  combinations  in  the  liver,  then 
we  can  expect  a  diminished  or  reduced  formation  of  urea  and  a 
corresponding  increase  in  the  elimination  of  ammonia  in  extirpa- 
tion of  the  liver.  The  normal  relationship  between  ammonia 
and  urea  in  the  urine  must  in  these  cases  be  essentially  changed. 
In  order  to  demonstrate  this,  experiments  have  been  made  on 
animals,  and  the  urine  in  men  with  liver  disease  has  been  ex- 
amined. 

The  extirpation  and  atrophy  experiments  on  animals  made  by 
different  methods  by  Nencki  and  Hahn,'  Slosse,^  and  Lieblein  ' 
have  shown  that  a  rather  marked  increase  of  ammonia  and  a 
diminished  elimination  of  urea  take  place  after  the  operation,  but 
also  that  there  are  cases  in  which,  irrespective  of  the  pronounced 
atrophy,  an  abundant  formation  of  urea  takes  place  and  no  appre- 
ciable if  any  change  in  the  proportion  of  ammonia  to  the  total 
nitrogen  and  urea  is  observed. 

The  observations  on  human  beings  with  diseases  of  the  liver  lead 
to  similar  results.  In  this  regard  the  numerous  investigations  of 
Hallerworden,*  Stadelmakk,'  Frakkel,'  Fawitzki,'  Morner 
and  Sjoqvist,"  Gumlich,'  v.  JSrooRDEK,'"  Weintraud,"  Munzer,'' 
and  WiNTERBERG  '^  and  others  on  the  urine  in  cirrhosis  of  the  liver, 
acute  yellow  atrophy  of  the  liver,  and  phosphorus  poisoning,  are 
available.  We  learn  from  these  investigations  that  in  certain  cases 
the  proportion  of  the  nitrogenous  substances  may  be  so  changed 
that  urea  is  only  50-60^  of  the  total  nitrogen,  while  in  other  cases, 
on  the  contrary,  even  in  very  extensive  atrophy  of  the  liver-cells, 
the  formation  of  urea  is  not  diminished,  neither  is  the  proportion 

>  L.  c. 

»  Du  Bois-Reymond's  Arch.,  1890. 

8  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  32. 

"  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  12. 

5  Deatsch.  Arch.  f.  klin.  Med.,  Bd.  33. 

«  Berlin  klin.  Wochenschr.,  Jahrg.  1878  and  1892. 

■1  Deutsch.  Arch.  f.  klin.  Med.,  Bd.  45. 

8  Skand.  Arch.  f.  Physiol.,  Bd.  2;  see  also  Sjoqvist,  Nord.  med.  Arkiv., 
Jahrg.  1892,  No.  86. 

9  Zeitschr.  f.  physiol.  Chem..  Bd.  17. 

>•  Lehrb.  d.  Pathol,  des  StofEwechsels,  S.  287. 

"  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  31. 

'*  Deutsch.  Arch.  f.  klin.  Med.,  Bd.  52. 

'*  Miinzer  and  Winterberg,  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  33. 


PROPERTIES  AND  REACTIONS    OF   UREA.  459 

between  the  total  nitrogen,  urea,  and  ammonia  essentially  changed. 
Even  in  the  cases  in  which  the  formation  of  urea  was  relatively 
diminished  and  the  elimination  of  ammonia  considerably  increased 
we  must  not  without  further  investigation  assume  a  reduced  abil- 
ity of  the  organism  to  produce  urea.  An  increased  elimination  of 
ammonia  may,  as  shown  by  Munzek  in  the  case  of  acute  phosphorus 
poisoning,  be  dependent  upon  the  formation  of  abnormally  large 
quantities  of  acids,  caused  by  abnormal  metabolism,  and  these  acids 
require  a  greater  quantity  of  ammonia  for  their  neutralization. 

For  the  present  we  are  not  justified  in  the  statement  that  the 
liver  is  the  only  organ  in  which  urea  is  formed,  and  continued 
investigation  only  can  yield  further  information  as  to  the  extent 
and  importance  of  the  formation  of  urea  from  ammonia  compounds 
in  the  liver. 

Properties  and  Reactions  of  Urea.  Urea  crystallizes  in  needles 
or  in  long,  colorless,  four-sided,  often  hollow,  anhydrous  rhombic 
prisms.  It  has  a  neutral  reaction  and  produces  a  cooling  sensation 
on  the  tongue  like  saltpetre.  It  melts  at  130-132°  C,  but  decom- 
poses already  at  about  100°  C.  At  ordinary  temperatures  it  dis- 
solves in  equal  weight  of  water  and  in  five  parts  alcohol;  it  requires 
one  part  boiling  alcohol  for  solution;  it  is  insoluble  in  alcohol-free 
ether  and  also  in  chloroform.  If  urea  in  substance  is  heated 
in  a  test-tube,  it  melts,  decomposes,  gives  off  ammonia,  and  leaves 
finally  a  non-transparent  white  residue  which,  among  other  sub- 
stances, contains  also  cyanuric  acid  and  biuret,  which  dissolves  in 
water,  giving  a  beautiful  reddish-violet  liquid  with  copper  sulphate 
and  alkali  {biuret  reaction).  On  heating  with  baryta-water  or 
caustic  alkali,  also  in  the  so-called  alkaline  fermentation  of  urine 
caused  by  micro-organisms,  urea  splits  into  carbon  dioxide  and 
ammonia  with  the  addition  of  water.  The  same  decomposition 
products  are  jiroduced  when  urea  is  heated  with  concentrated  sul- 
phuric acid.  An  alkaline  solution  of  sodium  hypobromite  decom- 
poses urea  into  nitrogen,  carbon  dioxide,  and  water  according  to 
the  equation 

CON",H^  -f  3NaOBr  =  3NaBr  +  CO,  +  2H,0  +  N,. 

With  a  concentrated  solution  of  furfurol  and  hydrochloric  acid 
urea  in  substance  gives  a  coloration  passing  from  yellow,  green, 
blue  to  violet  and  then  beautiful  purple-violet  after  a  few  minutes 


460  TEE   URINE. 

(Schiff's  '  reaction).  According  to  Huppekt  ^  the  test  is  best  per- 
formed by  taking  2  c.  c.  of  a  concentrated  furfurol  solution,  4-6 
drops  concentrated  hydrochloric  acid,  and  adding  to  this  mixture, 
which  must  not  be  red,  a  small  crystal  of  urea.  A  deep  violet 
coloration  appears  in  a  few  minutes. 

Urea  forms  crystalline  combinations  with  many  acids.  Among 
these  the  one  with  nitric  acid  and  the  one  with  oxalic  acid  are  the 
most  important. 

Urea  ISTitrate,  C0(NH2),.HN03.  On  crystallizing  quickly 
this  combination  forms  thin  rhombic  or  six-sided  overlapping  tiles, 
colorless  plates,  whose  point  has  an  angle  of  82°.  When  crystal- 
lizing slowly,  larger  and  thicker  rhombic  pillars  or  plates  are 
obtained.  This  combination  is  rather  easily  soluble  in  pure  water, 
but  is  considerably  less  soluble  in  water  containing  nitric  acid;  it 
may  be  obtained  by  treating  a  concentrated  solution  of  urea  with 
an  excess  of  strong  nitric  acid  free  from  nitrous  acid.  On  heat- 
ing this  combination  it  volatilizes  without  leaving  a  residue. 

This  compound  may  be  employed  with  advantage  in  detecting  smill 
amounts  of  urea.  A  drop  of  the  concentrated  solution  is  placed  on  a  micro- 
scope-slide and  the  cover-glass  placed  upon  it;  a  drop  of  nitric  acid  is  then 
placed  on  the  side  of  the  cover-glass  and  allowed  to  flow  under.  The  forma- 
tion of  crystals  begins  where  the  solution  and  the  nitric  acid  meet.  Alkali 
nitrates  may  crystallize  very  similarly  to  urea  nitrate  when  they  are  contam- 
inated with  other  bodies;  therefore,  in  testing  for  urea,  the  crystals  must  be 
identified  as  urea  nitrate  by  heating  and  by  other  means. 

Urea  Oxalate,  2.CO(]SrH.Jj.H2C20,.  This  compound  is  more 
sparingly  soluble  in  water  than  the  nitric-acid  compound.  It  is 
obtained  in  rhombic  or  six-sided  prisms  or  plates  on  adding  a 
saturated  oxalic-acid  solution  to  a  concentrated  solution  of  urea. 

Urea  also  forms  combinations  with  mercuric  nitrate  in  variable 
proportions.  If  a  very  faintly  acid  mercuric-nitrate  solution  is 
added  to  a  two-per-cent  solution  of  urea  and  the  mixture  carefully 
neutralized,  a  combination  is  obtained  of  a  constant  composition 
which  contains  for  every  10  parts  of  urea  72  parts  mercuric  oxide. 
This  compound  serves  as  the  basis  of  Liebig's  titration  method. 
Urea  combines  also  with  salts,  forming  mostly  crystallizable  com- 
binations, as,  for  instance,  with  sodium  chloride,  with  the  chlorides 
of  the  heavy  metals,  etc.  An  alkaline  but  not  a  neutral  solution 
of  urea  is  precipitated  with  mercuric  chloride. 

The  method  of  preparing  urea  from  urine  is  chiefly  as  follows: 
Concentrate  the  urine,  which  has  been  faintly  acidified  with  sul- 

'  Ber.  d.  deutsch.  chem.  Gesellsch..  Bd.  10. 

^  Huppert-Neubauer,  Analyse  des  Harnes,  10.  Aiifl.,  S.  296. 


ESTIMATION  OF  UREA.  461 

phnric  acid,  at  a  low  tempei'ature,  add  an  excess  of  nitric  acid,  at 
the  same  time  keeping  the  mixture  cool,  press  the  precipitate  well, 
decompose  it  in  water  with  freshly  precipitated  barium  carbonate, 
dry  on  the  water-bath,  extract  the  residue  with  strong  alcohol, 
decolorize  when  necessary  with  animal  charcoal,  and  filter  while 
warm.  The  urea  which  crystallizes  on  cooling  is  purified  by 
recrystallization  from  warm  alcohol.  A  further  quantity  of  urea 
may  be  obtained  from  the  mother-liquor  by  concentration.  The 
nrea  is  purified  from  contaminating  mineral  bodies  by  redissolving 
in  alcohol-ether.  If  it  is  only  necessary  to  detect  the  presence  of 
nrea  in  urine,  it  is  sufficient  to  concentrate  a  little  of  the  urine  on 
a  watch-glass  and  after  cooling  treat  with  an  excess  of  nitric  acid. 
In  this  way  we  obtain  crystals  of  urea  nitrate. 

Quantitative  Estimation  of  Urea  in  urine.  The  methods  sug- 
gested for  this  purpose  are  those  of  Liebig  by  titration,  of  Heintz 
and  Ragsky,  also  that  of  Kjeldahl,  by  which  the  total  nitrogen 
is  determined,  and  those  of  Bunsex  and  Kxcp-HiiFXER  and 
Morner-Sjoqyist,  where  urea  is  intended  to  be  determined  as 
such.  Among  these  methods,  that  of  Liebig,  which  is  perhaps  the 
one  most  frequently  employed  by  physicians,  and  that  of  Mokn'ER- 
Sjoqvist  will  here  be  carefully  explained.  In  regard  to  the  others, 
whose  chief  points  only  will  be  spoken  of  here,  the  student  is 
referred  to  other  text-books. 

Liebig's  method  is  based  upon  the  fact  that  a  dilute  solution 
of  mercuric  nitrate  under  proper  conditions  precipitates  all  the  urea, 
forming  a  compound  of  constant  composition.  As  indicator,  a  soda 
solution  or  a  thin  paste  of  sodium  bicarbonate  is  used.  An  excess 
of  mercuric  nitrate  produces  herewith  a  yellow  or  yellowish-brown 
combination,  while  the  combination  of  urea  and  mercury  is  white. 
Pfluger  '  has  given  full  particulars  of  this  method;  therefore  we 
will  describe  Pfluger's  modification  of  Liebig's  method. 

As  phosphoric  acid  is  also  precipitated  by  the  mercuric-nitrate 
solution,  this  must  be  removed  from  the  urine  by  the  addition  of  a 
baryta  solution  before  titration.  Pfluger  also  suggested  that  the 
acidity  produced  by  the  mercury  solution  be  neutralized  during 
titration  by  the  addition  of  a  soda  solution.  The  liquids  necessary 
for  tlie  titration  are  the  following: 

1.  Mercuric  X it  rate  Solution.  This  solution  is  calculated  for 
a  2^  urea  solution,  and  20  c.  c.  of  the  first  should  correspond  to  10 
c.  c.  of  the  latter.  Each  c.  c.  of  the  mercury  solution  corresponds 
to  0.01  grm.  urea.  As  a  small  excess  of  HgO  is  necessary  in  the 
urine  to  make  the  final  reaction  (with  alkali  carbonate  or  bicar- 
bonate) ajjpear,  each  c.  c.  of  the  mercury  solution  must  contain 

'  Pfluger,  andPfliiger  and  Boliland,  in  Pfluger's  Arch.,  Bdd.  31,  36,  37,  and 
40. 


462  THE   URINE. 

0.0772  instead  of  0.0720  grm,  HgO.     The  mercury  solution  con- 
tains therefore  77.2  grms.  HgO  in  one  litre. 

The  solution  may  be  prepared,  from  pure  mercury  or  mercuric  oxide  by  dis- 
solving in  nitric  acid.  Tiie  soluiion,  freed  as  completely  as  possible  from  an 
excess  of  acid,  is  diluted  by  the  careful  addition  of  water,  stirring  meanwhile, 
until  it  has  a  specific  gravity  of  1.10  or  a  little  higher  at  -f-  20°  C.  The  solu- 
tion is  staudai'dizsd  with  a  2%  solution  of  pure  urea  which  has  been  dried  over 
sulphur  c  acid,  and  the  operation  conducted  as  will  be  described  later.  If  the 
solution  is  too  concentrated,  it  is  corrected  by  the  careful  addition  of  the  neces- 
sary amount  of  water,  avoiding  precipitation  of  basic  salt,  and  titrating  again. 
The  solution  is  correct  if  19.8  c.  c.  of  it  added  at  once  to  10  c.  c.  of  the  urea 
solution  and  the  necessary  quantity  of  normal  soda  solution  (11-13  c.  c.  or  more) 
to  n  arly  c  impletely  neutralize  the  liquid,  gives  the  final  reaction  when  exactly 
20  c.  c.  of  the  mercury  solution  have  been  employed. 

2.  Baryta  Solution.  This  consists  of  1  vol.  barium-nitrate  and 
2  vols,  barium-hydrate  solation,  both  saturated  at  the  ordinary 
temperature. 

3.  Normal  Soda  Solution.  This  solution  contains  53  grms,  pure 
anhydrous  sodium  carbonate  in  1  litre  of  water.  According  to 
Pfluger  a  solution  having  a  specific  gravity  of  1.053  is  sufficient. 
The  amount  of  this  soda  solution  necessary  to  completely  neutralize 
the  acid  set  free  during  the  titration  is  determined  by  titrating  with 
a  pure  2^  urea  solution.  To  facilitate  operations  a  table  can  be 
made  showing  the  quantity  of  soda  solution  necessary  when  from 
10  to  35  c.  c.  of  the  mercury  solution  is  used. 

Before  the  titration  the  following  must  be  considered.  The 
chlorides  of  the  urine  interfere  with  the  titration  in  that  a  part  of 
the  mercuric  nitrate  is  transformed  into  mercuric  chloride,  which 
does  not  precipitate  the  urea.  The  chlorides  of  the  urine  are  there- 
fore removed  by  a  silver-nitrate  solution,  which  also  removes  any 
bromine  or  iodine  combinations  which  may  exist  in  the  urine.  If 
the  urine  contains  proteid  in  noticeable  amounts,  it  must  be 
removed  by  coagulation  and  the  addition  of  acetic  acid,  but  care 
must  be  taken  that  the  concentration  and  the  volume  of  the  urine 
is  net  changed  during  these  operations.  If  the  urine  contains 
ammonium  carbonate  in  notable  quantities,  caused  by  alkaline 
fermentation,  this  titration  method  cannot  be  applied.  The  same 
is  true  of  urine  containing  leucin,  ty rosin,  or  medicinal  preparations 
precipitated  by  mercuric  nitrate. 

In  cases  where  the  urine  is  free  from  proteid  or  sugar  and  not 
specially  poor  in  chlorides,  the  quantity  of  urea,  and  also  the 
approximate  quantity  of  mercuric  nitrate  necessary  for  the  titration, 
mav  be  learned  from  the  specific  gravity.  A  specific  gravity  of 
1.010  corresponds  to  about  10  p,  m,,  a  specific  gravity  of  1.015 
generally  somewhat  less  than  15  p.  m,,  and  a  specific  gravity  of 
1.015-1.020  about  15-20  p.  m.  urea.  With  a  specific  gravity 
higher  than  1.020  the  urine  generally  contains  more  than  20  p.  m. 
of  urea,  and  above  this  point  the  amount  of  urea  increases  much 
more  rapidly  than  the   specific  gravity,   so    that  with  a  specific 


ESTIMATION  OF   UREA.  463 

gravity  of  1.030  it  contains  over  40  p.  m.  urea.  Fever  urines 
with  a  specific  gravity  above  1.020  sometimes  contain  30-40  p.  m. 
urea,  or  even  more. 

Preparation  for  the  Titration.  If  a  large  amount  of  urea 
is  suspected  from  a  higii  specific  gravity,  the  urine  must  first  be 
diluted  with  a  carefully  measured  quantity  of  water,  so  that  the 
amount  of  urea  is  reduced  belo^  30  p.  m.  In  a  special  portion  of 
the  same  urine  the  amount  of  chlorides  is  determined  by  one  of  the 
methods  which,  will  be  given  later,  and  the  number  of  c.  c.  of 
silver-nitrate  solution  necessary  is  noted.  Then  a  larger  quantity 
of  urine,  say  100  c.  c,  is  mixed  with  one  half  or,  if  this  is  not 
sufficient  to  precijiitate  all  the  sulphuric  and  phosphoric  acids,  with 
an  equal  volume  of  the  baryta  solution:  it  is  then  allowed  to  stand 
a  little  while,  and  the  precipitate  is  filtered  through  a  dried  filter. 
From  the  filtrate  contaiuing  the  urine  diluted  with  water  a  proper 
quantity,  corresponding  to  about  60  c.  c.  of  the  original  urine,  is 
measured,  and  exactly  neutralized  with  nitric  acid  added  from  a 
burette,  so  that  the  exact  quantity  employed  is  known.  The 
neutralized  mixture  of  urine  and  baryta  is  treated  with  the  proper 
quantity  of  silver-nitrate  solution  necessary  to  completely  precipitate 
the  chlorides,  which  was  ascertained  by  a  previous  determination. 
The  mixture  containing  a  known  volume  of  urine  is  now  filtered 
through  a  dried  filter  into  a  flask,  and  from  the  filtrate  an  amount 
is  measured  corresponding  to  10  c.  c.  of  the  original  urine. 

Execution  of  the  Titration.  Nearly  the  total  quantity  of 
mercuric-nitrate  solution  to  be  used,  and  which  is  known  from  the 
specific  gravity  of  the  urine,  is  added  at  once,  and  immediately 
afterwards  the  quantity  of  soda  solution  necessary,  as  indicated  by 
the  table.  If  the  mixture  becomes  yellowish  in  color,  then  too 
much  mercury  solution  has  been  added  and  another  determination 
must  be  made.  If  the  test  remains  white,  and  if  a  drop  taken  out 
and  placed  on  a  glass  plate  with  a  dark  background  and  stirred  with 
a  drop  of  a  thin  paste  of  sodium  bicarbonate  does  not  give  a  yellow 
color,  the  addition  of  mercury  solution  is  continued  by  adding  ^ 
and  then  -^^  c.  c,  and  testing  after  each  addition  in  the  following 
way:  A  drop  of  the  mixture  is  placed  on  a  glass  plate  with  a  dark 
background  beside  a  small  drop  of  tlie  bicarbonate  paste.  If  the 
color  after  stirring  the  two  drops  together  is  still  white  after  a  few 
seconds,  then  more  mercury  solution  must  be  added;  if,  on  the 
contrary,  it  is  yellowish,  then — if  not  too  much  mercury  solution 
has  been  added  by  inattention — the  result  to  yV  ^-  ^-  ^^^^  been 
found.  By  this  approximate  determination,  which  is  sufficient  in 
many  cases,  we  have  fixed  the  minimum  amount  of  mercury 
solution  necessary  to  add  to  the  quantity  of  urine  in  question,  and 
we  now  proceed  to  the  final  determination. 

A  second  quantity  of  the  filtrate,  corresponding  to  10  c.  c.  of 
the  original  urine,  is  filtered,  and  the  same  quantity  of  mercury 
solution  added  at  one  time  as  was  found  necessary  to  produce  the 


464  THE   URINE. 

final  reaction,  and  immediately  after  the  corresponding  amount  of 
soda  solution,  which  must  not  indicate  the  end  of  the  reaction. 
Then  add  the  mercury  solution  in  Jj-  c.  c.  without  neutralizing  with 
soda,  until  a  drop  taken  out  and  mixed  with  the  soda  solution  gives 
a  yellow  coloration.  If  this  final  reaction  is  obtained  after  the 
addition  of  0,1-0.2  c.  c,  then  the  titration  may  be  considered  as 
finished.  If,  on  the  contrary,  a  larger  quantity  is  necessary,  the 
addition  of  the  mercury  solution  must  be  continued  until  a  final 
reaction  is  obtained  with  simple  carbonate,  and  the  titration 
repeated  again,  adding  the  quantity  of  mercury  solution  used  in  the 
previous  test  at  one  time,  and  also  adding  the  corresponding  amount 
of  soda  solution.  If  we  obtain  the  end  reaction  by  the  addition  of 
■ji„  c.  c,  we  may  consider  the  titration  as  finished. 

If  in  each  titration  a  quantity  of  filtrate  containing  urine  and 
baryta  corresponding  to  10  c.  c.  of  the  original  urine  is  used,  then 
the  calculations  are  very  sim2:)le,  since  1  c.  c.  of  mercuric-nitrate 
solution  corresponds  to  0.01  grm.  of  urea.  As  the  mercury  solution 
is  made  for  a  2^  urea  solution,  the  filtrate  of  urine  and  baryta  being 
generally  deficient  in  urea  (if  the  quantity  of  urea  is  above  2^,  it  is 
easy  to  avoid  any  mistake  by  dilating  the  urine  at  the  beginning  of 
the  operation),  a  mistake  occurs  here  which  can  be  corrected  in  the 
following  way,  according  to  Pfluger  :  To  the  measured  volume  of 
the  filtrate  from  the  urine  (the  filtrate  with  baryta  after  neutraliza- 
tion with  nitric  acid,  precipitation  with  silver  nitrate  and  filtration) 
the  quantity  of  normal  soda  solution  employed  is  added,  and  from 
this  sum  the  volume  of  mercury  solution  used  is  subtracted.  The 
remainder  is  then  multiplied  by  0.08,  and  the  product  subtracted 
from  the  number  of  c.  c.  of  mercury  solution  used.  For  example, 
if  the  filtrate  (urine  and  baryta  -\-  nitric  acid  -j-  silver  nitrate) 
measured  25.8  c.  c,  and  the  number  of  c.  c.  of  soda  solution  used 
in  the  titration  13.8  c.  c,  and  the  mercury  solution  20. .5  c.  c,  we 
have  then  20.5  —  |(39.6  —  20.5)  X  0.08|  =  20.5  ~  1.53  =  18.97, 
and  the  corrected  quantity  of  mercury  solution  is  therefore  18.97 
c.  c.  If  the  measured  c.  c.  of  the  filtrate  (in  this  case  25.8  c,  c.) 
corresponds  to  10  c.  c.  of  the  original  urine,  then  the  amount  of 
urea  is  18.97  X  0.01  =  0.1897  =  18.97  p.  m.  urea. 

Besides  the  urea  other  nitrogenous  constituents  of  the  urine  are 
precipitated  by  the  mercury  solution.  In  the  titration  we  really  do 
not  obtain  the  quantity  of  urea,  but,  as  Pfluger  has  shown,  the 
total  quantity  of  nitrogen  in  the  urine  expressed  as  urea.  As  urea 
contains  46.67  p.  c.  N,  the  total  quantity  of  nitrogen  in  the  urine 
may  be  calculated  from  the  quantity  of  urea  found. 

The  results  obtained  by  Liebig-Pfluger's  titration  method  for 
the  total  nitrogen,  Pfluger  has  shown,  correspond  well  with  the 


ESTIMATION  OF  UREA.  465 

results  obtained  by  Kjeldahl's  '  niebhod,  which  was  first  (1860) 
nsed  by  Almen  '^  for  urea  determiaations,  and  modified  by  Pfluger 
and  BoHLAXD.''  This  method  consists  in  heating  the  urine  a  few 
hours  with  an  excess  of  concentrated  or  faming  sulphuric  acid 
(5  c.  c.  urine  and  40  c,  c.  sulphuric  acid)  until  all  the  nitrogen  has 
been  converted  into  ammonia,  and  after  the  addition  of  an  excess 

of  caustic  soda  the  ammonia  is  distilled  into  --  sulphuric  acid  and 

the  amount  of  ammonia  determined  by  titration. 

Bunsen's  '  Urea  Determination.  The  principle  of  this 
method  consists  in  heating  the  urine  or  urea  solution  in  a  sealed 
glass  tube  to  a  high  temperature  with  an  alkaline  barium-chloride 
eolation.  The  urea  splits  into  carbon  dioxide  and  ammonia,  which 
may  be  determined  separately.  This  method  has  been  very  care- 
fully tested  by  Pfluger  and  his  pupils  Borland  and  Bleibtreu," 
and  essentially  improved.  Tliey  found  that  very  accurate  results 
can  be  obtained  by  this  method  if  the  other  nitrogenous  constituents 
of  the  urine  are  first  precipitated  by  a  mixture  of  hydrochloric  acid 
and  phospho-tungstic  acid,  and  then  the  filtrate  made  faintly 
alkaline  with  milk  of  lime,  and  lastly  heated  with  alkaline  barium- 
chloride  solution  in  a  sealed  tube.  The  carbon  dioxide  and  the 
ammonia  can  be  determined  (by  distilling  with  magnesia  and  receiv- 

ing  the  distillate  in  — -  acid  and  titrating).     In  the  last  case  a  cor- 

rection  must  be  made  (according  to  Schlosing's  method)  for  the 
ammonia  pre-existing  in  the  urine.  Pfluger  and  Bleibtreu  have 
essentially  changed  this  method  in  the  following  way :  They  pre- 
cipitate the  other  nitrogenous  urinary  constituents  with  hydro- 
chloric acid  and  phospho-tungstic  acid,  make  the  filtrate  faintly 
alkaline  with  milk  of  lime,  determine  the  pre-existing  ammonia  in 
a  part  of  this  filtrate  according  to  Schlosing's  method  (observing 
certain  precautions),  and  then  placing  the  other  part  of  the  filtrate 
(about  15  c.  c.)  in  a  large  flask  which  contains  10  grms.  crystallized 
phosphoric  acid,  heat  to  230-260°  C.  for  about  three  hours.  All 
the  urea  is  decomposed,  and  the  ammonia  split  off  combines  with 

'  Zeitschr.  f.  anal.   Cliem.,   Bd.   22;  also  Wilfartb,  Chem.  Centralbl.,  1885, 
and  Argutinsky,  Pfluger 's  Arch.,  Bd.  46. 

'^  Aug.  Almen,  Om  urinafsondring  och  Uraemie.     Dissert.     Upsala,  1860. 
3  Pfluger's  Arcb.,  Bdd.  35,  36,  and  44. 
*  Anal.  d.  Cliem.  u.  Pbarni.,  Bd.  65. 
&  Paiiger's  Arcb.,  Bdd.  38,  43.  and  44. 


466  THE    URINE. 

the  phosphoric  acid.  After  cooling,  an  excess  of  caustic  soda  is 
added  and  the  ammonia  distilled  into  a  titrated  acid,  which  must 
then  be  retitrated.  After  subtracting  the  quantity  of  pre-existing 
ammonia  very  accurate  results  are  obtained  for  the  ammonia  orig- 
inating from  the  urea  (and  perhaps  from  an  unknown  ureid  present 
in  the  urine). 

Knop-Hufkee's  method  '  is  based  on  the  fact  that  urea  by  the 
action  of  sodium  hypobromite  splits  into  water,  carbon  dioxide 
(which  dissolves  in  the  alkali),  and  nitrogen,  whose  volume  is 
measured  (see  page  459).  This  method  is  less  accurate  than  the 
preceding  ones,  and  therefore  in  scientific  work  it  is  discarded.  It 
is  of  value  to  the  physician  and  for  practical  purposes  because  of  the 
ease  and  rapidity  with  which  it  may  be  performed,  even  thoagh  it 
may  not  give  very  accurate  results.  For  practical  purposes  a  series 
of  different  apparatus  have  been  constructed  to  facilitate  the  use  of 
this  method.^  Among  these  Esbach's  tireometer  deserves  to  be 
especially  mentioned.  In  regard  to  the  reagents  necessary  for  the 
determination  of  urea,  and  also  for  instructions  in  the  use  of  this 
instrument,  we  must  refer  the  reader  to  the  directions  accompany- 
ing the  apparatus.  For  pure  urea  solations  Esbach's  apparatus 
gives  qaite  exact  results.  The  determination  of  urea  in  urine  by 
this  method  always  gives  results  somewhat  too  low,  and  as  a  rule  a 
result  is  obtained  which  on  an  average  is  about  0.1^  lower  than  that 
obtained  with  Liebig's  titration  method. 

Morner-Sjoqvist  Method.^  According  to  this  method  the 
nitrogenous  constituents  of  the  urine,  with  the  exception  of  the 
urea  and  ammonia,  are  first  precipitated  by  alcohol-ether  after  the 
addition  of  a  solution  of  barium  chloride  and  barium  hydrate  and 
then  the  urea  determined  in  the  concentrated  filtrate,  after  driving 
off  the  ammonia,  by  Kjeldahl's  nitrogen  estimation. 

The  procedure  is  as  follows:  Mix  5  c.  c.  of  the  urine  in  a  flask 
with  5  c.  c.  saturated  BaCl^  solution,  in  which  bi  barium  hydrate 
is  dissolved.  Then  add  100  c.  c.  of  a  mixture  of  two  parts  97^ 
alcohol  arrid  1  part  ether  and  allow  this  to  stand  in  the  closed  flask 
overnight.  The  precipitate  is  filtered  off  and  washed  with  alcohol- 
ether.     The  alcohol  and  ether  is  removed  from  the  filtrate  by  dis- 

'  Knop,  ZeitscLr.  f.  analyt.  Chem.,  Bd.  9;Hu.fner,  Jour.  f.  prakt.  Chem.  (N 
F.),  Bd.  3.     See  also  Huppert-Neubauer,  10.  Aufl. 

2  S  '6  Huppert-Neubauer. 

3  Skand.  Arcli.  f.  Pliysiol.,  Bd.  2. 


CREATIMK  i67 

tillation  at  about  55°  C.  (not  above  60°  C).  When  the  liquid  is 
reduced  to  about  25  c.  c.  a  little  water  and  calcined  magnesia  are 
added  and  the  evaporation  continued  until  the  vapors  are  no  longer 
alkaline  in  reaction,  which  generally  is  found  before  it  is  concen- 
trated to  15-10  c.  c.  This  concentrated  liquid  is  transferred  into 
a  proper  flask  by  the  aid  of  a  little  water,  treated  with  a  few  drops  of 
concentrated  sulphuric  acid  and  further  concentrated  on  the  water- 
bath.  Now  20  c.  c.  pure  concentrated  sulphuric  acid  are  added 
and  the  process  carried  out  according  to  Kjeldahl.  According  to 
BoDTKER  '  the  addition  of  magnesia  is  unnecessary,  and  it  is  best  to 
avoid  it  entirely  as  it  easily  leads  to  a  small  loss  of  urea.  This 
exact  method  is  to  be  recommended, 

Carbamic  Acid,  HaN.COOII.  This  acid  is  not  known  in  the  free  state,  but 
only  as  salts.  Ammonium  carbamate  is  produced  by  tlie  action  of  dry  ammo- 
nia on  dry  carbon  dioxide.  Carbamic  acid  is  also  produced  by  the  action  of 
potassium  permanganate  on  proteid  and  several  other  nitrogenous  organic 
l)odies. 

We  have  already  spoken  of  the  occurrence  of  carbamic  acid  in  human  and 
animal  urines  in  connection  with  the  formation  of  urea.  The  calcium  salt, 
which  is  soluble  in  water  and  ammonia  but  insoluble  in  alcohol,  is  most  im- 
portant in  the  detection  of  this  acid.  The  solution  of  the  calcium  salt  in  water 
becomes  cloudy  on  standing,  but  much  quicker  on  boiling,  and  calcium  car- 
bonate separates. 

Carhamic  acid  ethylester  (urethan),  as  shown  by  Jaffe,'  may  pass,  by  the 
mutual  action  of  alcohol  and  urea,  into  the  alcoholic  extract  of  the  urine  when 
working  with  large  quantities  of  urine. 

Creatinin,  C^H,N,0,  or  NH  :  C<(^  TST/prr  \  pu-  >  i^  generally  con- 
sidered as  the  anhydride  of  creatin  (see  page  366)  found  in  the 
muscles.  It  occurs  in  human  urine  and  in  that  of  certain  mam- 
malia. It  has  also  been  found  in  ox-blood,  milk,  though  in  very 
small  amounts,  and  in  the  flesh  of  certain  fishes.  According  to 
Johnson  '  a  creatinin  occurs  in  fresh  ox-flesh  which  differs  from 
tiiat  occurring  in  urine  and  from  which  the  creatin  of  the  muscles 
is  formed  by  bacterial  action. 

The  quantity  of  creatinin  in  human  urine  is  for  a  grown  man, 
voiding  a  normal  quantity  of  urine  in  the  24  hours,  O.G-1.3  grrns. 
(Neubauer^),  or  on  an  average  1  grni.  The  quantity  is  dependent 
on  the  food,  and  decreases  in  starvation.  Sucklings  do  not  gen- 
erally eliminate  any  creatinin,  and  it  only  appears  in  the  urine  when 

>  Zeitschr.  f.  physiol.  Chem.,    Bd.  17. 

»m-d,Bd.  14. 

»  Proc.  Koy.  Soc,  Vol.  50.     Cited  from  Maly's  Jahresber.,  Bd.  22. 

*  Huppert-Neubauer,  Ilarnanalyse,    10.  Aufl.,   S.  387. 


468  THE   URINE. 

the  milk  is  replaced  by  other  food.  The  quantity  of  creatinin  in 
nrine  varies  as  a  rnle  with  the  quantity  of  urea,  although  it  is 
increased  more  by  flesh  (because  the  flesh  contains  creatin)  than  by 
proteid.  Gkocco  ^  and  Moitbssiee '•^  claim  that  the  elimination  of 
creatinin  is  increased  by  muscular  activity.  The  behavior  of 
creatinin  in  disease  is  little  known.  By  increased  metabolism  the 
amount  is  increased,  while  by  decreased  exchange  of  material,  as  in 
anaemia  and  cachexia,  it  is  diminished. 

Creatinin  crystallizes  in  colorless,  shining  monoclinic  prisms 
which  differ  from  creatin  crystals  in  not  becoming  white  with  loss 
of  water  when  heated  to  100°  C.  It  dissolves  in  11. o  parts  cold 
water,  but  more  easily  in  warm  water.  It  requires  nearly  100  parts- 
cold  absolute  alcohol  for  solution,^  but  it  is  more  soluble  in  warm 
alcohol.  It  is  nearly  insoluble  in  ether.  In  alkaline  solution 
creatinin  is  converted  into  creatin  very  easily  on  warming. 

Creatinin  gives  an  easily  soluble  crystalline  combination  with 
hydrochloric  acid.  A  solution  of  creatinin  acidified  with  mineral 
acids  gives  crystalline  precipitates  with  phospho-tungstic  or 
phospho-molybdic  acids  even  in  very  dilute  solutions  (1  :  10,000) 
(Keener,*  Hofmeister^).  It  is  precipitated,  like  urea,  by 
mercuric-nitrate  solution.  Among  the  compounds  of  creatinin, 
that  with  zinc  chloride,  creatmin  zinc- chloride,  (C^H,]S'30)jZaClj,  is 
of  special  interest.  This  combination  is  obtained  when  a  sufficiently 
concentrated  solution  of  creatinin  in  alcohol  is  treated  with  a  con- 
centrated, faintly  acid  solution  of  zinc  chloride.  Free  mineral  acids 
dissolve  the  combination,  hence  they  must  not  be  present;  this, 
however,  may  be  prevented,  when  they  are  present,  by  an  addition 
of  sodium  acetate.  In  the  impure  state,  as  ordinarily  obtained 
from  urine,  creatinin  zinc  chloride  forms  a  sandy,  yellowish  powder 
which  under  the  microscope  appears  as  fine  needles  forming  concen- 
tric groups,  mostly  complete  rosettes  or  yellow  balls  or  tufts,  or 
grouped  as  brushes.  On  slowly  crystallizing,  or  when  very  pure, 
more  sharply  defined  prismatic  crystals  are  obtained.  This  com- 
bination is  sparingly  soluble  in  water. 

Creatinin  acts  as  a  reducing  agent.     Mercuric  oxide  is  rednced 

'  See  Maly's  Jahresber.,  Bd.  16,  S.  199. 

'  Compt.  rend.  soc.  biol.,  Tome  43.      Cited  from  Maly's  Jahresber.,  Bd.  21. 
2  This  statement  is  taken  from  Huppert-Neubauer's  book.     Hoppe-Seyler's 
Handb.,  6.  Aufl.,  S.  144,  gives  other  figures. 
^  Pfliiger's  Arch.,  Bd.  2,  S.  220. 
'  Zeitschr.  f .  physiol.  Chem. ,  Bd.  5. 


PROPERTIES  AND  REACTIONS  OF  CREATININ.         469 

to  metallic  mercnry,  and  oxalic  acid  and  methylgnanidin  (methyl- 
uramin)  are  formed.  Creatinin  also  reduces  cojjper  hydroxide  in 
alkaline  solution,  forming  a  colorless  soluble  combination,  and  only 
after  continuous  boiling  with  an  excess  of  copper  salt  is  free  sub- 
oxide of  copper  formed.  Creatinin  interferes  with  Trommer's  test 
for  sugar,  partly  because  it  has  a  reducing  action  and  partly  by 
retaining  the  copper  suboxide  in  solution.  The  combination  with 
copper  suboxide  is  not  soluble  in  a  saturated-soda  solution,  and  if  a 
little  creatinin  is  dissolved  in  a  cold,  saturated-soda  solution  and 
then  a  few  drops  of  Fehlixg's  reagent  added,  a  white  fiocculent 
combination  separates  after  heating  to  50-60°  C.  and  then  cooling 
(y.  Maschke's  '  reaction).  An  alkaline  bismuth  solution  (see 
Sugar  Tests)  is  not  reduced  by  creatinin. 

If  we  add  a  few  drops  of  a  freshly  prepared  very  dilute  sodium 
nitroprusside  (sp.  gr.  1.003)  to  a  dilute  creatinin  solution  (or  to  the 
urine)  and  then  a  few  drops  of  caustic  soda,  a  ruby-red  liquid  is 
obtaiaed  which  quickly  turns  yellow  again  (Weyl's*  reaction).  If 
we  use  ammonia  instead  of  caustic  soda  in  this  reaction,  the  red 
color  is  not  obtained  (differing  from  acetone  and  diacetic  acid,  Le 
Nobel').  If  the  above  solution,  which  has  become  yellow,  is 
treated  with  an  excess  of  acetic  acid  and  heated,  the  solution 
becomes  first  green  and  then  blue  (Salkowski  *) ;  finally  a  precipi- 
tate of  Prussian  blue  is  obtained.  If  a  solution  of  creatinin  in  water 
(or  urine)  is  treated  with  a  watery  solution  of  picric  acid  and  a  few 
drops  of  a  dilute  caustic-soda  solution,  a  red  coloration  lasting 
several  hours  occurs  immediately  at  the  ordinary  temperature,  and 
which  turns  yellow  on  the  addition  of  acid  (Jaffe's  ^  reaction). 
Acetone  gives  a  more  reddish-yellow  color.  Grape-sugar  gives  with 
this  reagent  a  red  coloration  only  after  heating. 

In  preparing  creatinin  from  urine  the  creatinin  zinc  chloride  is 
first  prepared  according  to  Is'eubauer's^  method,  and  this  method 
is  also  employed  for  the  quantitative  estimation  of  creatinin.  In 
making  a  quantitative  estimation  200-300  c.  c.  of  urine  freed  from 
proleid  (by  boiling  with  acid)  and  from  sugar  (by  fermentation 
with  yeast)  are  measured,  alkalized  with  milk  of  lime,  and  treated 

'  Zeitschr.  f.  analyt.  Chem.,  Bd.  17. 

'  Ber.  d.  deutsch.  cbem.  Gesellsch.,  Bd.  11. 

»  Maly's  Jaliresber.,  Bd.  13,  S.  238. 

*  Zeitschr.  f.  physiol.  Chem.,  Bd.  4,  S.  133. 

'^  Ibid.,  Bd.  10. 

«  Ann.  d.  Chem.  u.  Pharm.,  Bd.  119. 


4:70  THE   URINE. 

with  CaClj  solation  until  all  the  phosphoric  acid  is  precipitated;  it 
is  filtered  and  washed  with  water,  the  filtrate  and  the  wash-water 
niiited,  and  evaporated  to  a  syrap  after  acidifying  with  acetic  acid. 
This  syrap  is  mixed  while  hot  with  50  c.  c.  of  95-97^  alcohol. 
This  mixture  is  transferred  to  a  beaker,  and  the  residue  in  the 
evaporatiag-dish  is  completely  and  carefully  removed  and  added. 
The  liquid  is  allowed  to  stand  covered  for  at  least  eight  hours  in  the 
cold.  Then  it  is  filtered  through  a  small  filter,  the  precipitate 
washed  with  alcohol,  the  filtrate  evaporated  if  necessary  until  the 
volume  is  50-60  c.  c,  then  allowed  to  cool  and  ^  c.  c.  of  an  acid- 
free  zinc-chloride  solution  of  a  specific  gravity  of  1.20  is  added;  it 
is  stirred,  and  the  covered  beaker  is  left  standing  in  a  cool  place  for 
two  or  three  days.  The  precipitate  is  collected  on  a  small  dried 
and  weighed  filter,  using  the  filtrate  to  wash  the  crystals  from  the 
beaker.  After  allowing  the  crystals  to  completely  drain  off,  they 
are  washed  with  a  little  alcohol  until  the  filtrate  gives  no  reaction 
for  chlorine,  and  dried  at  100°  C  100  parts  creatinin  zinc-chloride 
contain  62.44  parts  creatinin.  As  the  precipitate  is  never  quite 
pure,  the  quantity  of  zinc  must  be  carefully  determined,  in  exact 
experiments,  by  evaporating  with  nitric  acid,  heating,  washing  the 
oxide  of  zinc  with  water  (to  remove  any  NaCl),  drying,  heating, 
and  weighing.  22.4  parts  zinc  oxide  correspond  to  100  parts 
creatinin  zinc  chloride. 

The  preparation  of  creatinin  zinc  chloride  on  a  large  scale  from 
urine  is  done  in  the  same  way.  The  creatinin  is  obtained  from  the 
creatinin  zinc  chloride  by  boiling  with  lead  hydroxide,  filtering, 
decolorizing  the  filtrate  with  animal  charcoal,  evaporating,  treating 
the  residue  with  strong  alcohol  (which  leaves  the  creatin  undis- 
solved), evaporating  to  crystallization,  redissolving  in  water,  and 
recrystallizing. 

In  regard  to  the  modifications  of  Neubauer's  method  for  the 
quantitative  estimation  of  creatinin  the  reader  is  referred  to  Sal- 
KOWSKi.'  Kolisch'  has  given  a  new  method  for  estimating 
creatinin  in  urine  which  consists  in  precipitating  the  creatinin  from 
the  alcoholic  extract  by  an  alcoholic  solution  of  mercuric  chloride 
acidified  with  acetic  acid.  The  nitrogen  is  exactly  determined  in 
the  carefully  washed  precipitate  by  Kjeldahl's  method.  Kolisch 
uses  the  following  solution  as  precipitant:  30  parts  mercuric  chlo- 
ride, 1  part  sodium  acetate,  3  drops  glacial  acetic  acid,  and  125  parts 
absolute  alcohol. 

Xanthocreatinin,  CtlLoNiO.     This   body,  wliicli  was   first  prepared   from 
meat  extract  hj  Gautier,^  Las  been  found  by  Monari*  in  dog's  urine  after 

'  ZeitscLr.  f.  physiol  Chem.,  Bdd.  10  and  14. 

'^  Centralbl.  f.  innere  Medizin,  1895. 

'  Bull,  de  I'Acad.  de  med.  (2),  Tome  15,  and  Bull,  de  la  soc.  cbim.,  Tome 

48. 

*  See  Maly's  Jabresber.,  Bd.  17,  S.  182. 


URTG  ACID.  471 

the  injection  of  creatinin  into  the  abdominal  cavity,  and  in  human  urine  alter 
several  hours  of  exhausting  marches.  According  to  Colasanti  '  it  occurs 
to  a  relatively  greater  extent  in  lion's  urine.  Stadthagen'^  considers  the 
xanthocreatinin,  isolated  from  human  urine  after  strenuous  muscular  activity, 
as  impure  creatinin. 

Xanthocreatinin  forms  sulphur-yellow  thin  plates,  similar  to  cholesterin, 
which  have  a  bitter  taste.  It  dissolves  in  cold  water  and  in  alcohol,  and  gives 
a  crystalline  combination  with  hydrochloric  acid  and  a  double  compound  with 
gold  and  platinum  chloride.  It  gives  a  combination  with  zinc  chloride,  which 
crystallizes  in  fine  needles.     Xanthocreatinin  has  a  poisonous  action. 

Uric  Acid,  Ur,  C^H^jST^O,.     The  structural  formula  of  this  acid, 

/NH.C.NH\ 
according  to  Medicus,  is  C0<(  C.NH/^^'  '^^^^   *^^^   ^°^^ 

\HN.CO 
may  therefore  be  considered,  from  its  constitution  as  a  derivative  of 
acrylic  acid,  as  acrylic  acid  diureid. 

Uric  acid  has  been  synthetically  prepared  by  Horbaczewski  ' 
in  several  ways.  On  fusing  urea  and  glycocoll,  uric  acid  is  formed 
according  to  the  formula  3C0NJI,  +  C,H,NO,  =  C.H.N.O,  + 
2H,0  +  3NH3,  and  in  this  reaction  hydantoin  and  biuret  are 
formed  as  intermediate  products.  On  melting  methylhydantoin 
with  urea  or  methylhydantoin  with  biuret  or  with  allophanic-acid 
amyl-ester  Horbaczewski  obtained  methyl-uric  acid.  He  also 
obtained  uric  acid  on  heating  trichlor-lactic  acid,  or  still  better 
trichlor-lactic  acid-amid,  with  an  excess  of  urea.  If  we  eliminate 
from  the  reaction  the  numerous  by-products  (cyanuric  acid,  carbon 
dioxide,  etc.),  then  this  p-ocess  may  be  expressed  by  the  formula 
C,CI,H,0,N  4-  2C0N,H,  =  C,H,N,0,  -f  H,0  +  NH.Cl  +  2HC1. 

On  strongly  heating  uric  acid  it  decomposes  with  the  formation 

of    UREA,    HYDROCYANIC    ACID,    CYAJSTURIC    ACID,    and    AMMONIA. 

On  heating  with  concentrated  hydrochloric  acid  in  sealed  tubes  to 
170°  C.  it  splits  into  glycocoll,  carbon  dioxide,  and  ammonia. 
By  the  action  of  oxidizing  agents  a  splitting  and  oxidation  takes 
place,  and  either  monoureid  or  diureid  is  produced.  By  oxidation 
with  lead  peroxide,  carbon  dioxide,  oxalic  acid,  urea,  and 
ALLANTOiN,  which  last  is  glyoxyldiureid,  are  produced  (see  below). 

'  Arch.  ital.  de  Biologie,  Tome  15. 
»  Zeitschr.  f.  klin.  Med. ,  Bd.  15. 

*  Monatshefte  f.  Chem.,  Bdd.  6  and  8.     See  also  Behrend  and  Roosen,  Ber. 
d.  deutsch.  chem.  Gesellsch.,  Bd.  21,  S.  999. 


472  THE    URINE. 

Bv  oxidation  with  nitric  acid  in  the  cold  urea  and  a  monoureid, 
the  mesoxalyl  urea  or  alloxan,  are  obtained,  C^H^lST^Og  +  0  +  ■ 
H^O  =  C^H^N^O,  +  (NHJjCO.  On  warming  with  nitric  acid, 
alloxan  yields  carbon  dioxide,  and  oxalyl  urea  or  parabanic  acid, 
iCjHjNjOj.  By  the  addition  of  water  the  parabanic  acid  passes  into 
OXAlueic  acid,  CjH^N^O^,  traces  of  which  are  found  in  the  urine 
and  which  easily  split  into  oxalic  acid  and  urea. 

Uric  acid  occurs  most  abundantly  in  the  urine  of  birds  and  of 
scaly  amphibians,  in  which  animals  tlie  greater  part  of  the  nitrogen 
of  the  urine  appears  in  this  form.  Uric  acid  occurs  frequently  in 
the  urine  of  carnivorous  mammalia,  bat  is  sometimes  absent;  in 
urine  of  herbivora  it  is  habitually  present,  though  only  as  traces; 
in  human  urine  it  occurs  in  greater  but  still  small  and  variable 
amounts.  Traces  of  uric  acid  are  also  found  in  several  organs  and 
tissues,  as  in  the  spleen,  lungs,  heart,  pancreas,  liver  (especially  in 
birds),  and  in  the  brain.  It  habitually  occurs  in  the  blood  of  birds 
(Meissis  EE ') .  Traces  have  been  found  in  human  blood  under 
normal  conditions  (Abeles^).  Under  pathological  conditions  it 
occurs  to  an  increased  extent  in  the  blood  in  pneumonia 
(v.  Jaksch'),  but  also  in  leucamia  and  arthritis.  Uric  acid  also 
occurs  in  large  quantities  in  "  chalk-stones,"  certain  urinary 
calculi,  and  in  guano.  It  has  also  been  detected  in  the  urine  of 
insects  and  certain  snails. 

The  amount  of  uric  acid  eliminated  with  the  human  urine  is 
subject  to  considerable  variation,  but  amounts  on  an  average  to 
0.7  grm.  during  24  hours  on  a  mixed  diet.  The  relationship  of  the 
uric  acid  to  the  urea  on  a  mixed  diet  is  on  an  average  1  :  50-1  :  70.' 
In  new-born  infants  and  in  the  first  days  of  life  the  elimination  of 
uric  acid  is  increased  (Maees  *),  and  the  relation  between  the  uric 
acid  and  urea  is  about  1  :  13-14.  Sjoqvist  °  found  the  relationship 
in  new-born  infants  to  be  1  :  6.42-17,1. 

'  Zeitschr.  f.  rat.  med.  (3),  Bd.  31.  Cited  from  Hoppe-Seyler's  Physiol. 
Chem.,  S.  432. 

*  Wien.  med.  Jahrbiiclier,  1887.     Cited  from  Maly's  Jahresber. ,  Bd.  17. 

*  Ueber  die  klin.  Bedeutung  des  Vorkommens  der  Harnsaure,  etc.  Prager 
Festschrift.     Berlin,  1896.     S.  79. 

*  A  very  good  tabular  summary  of  the  variation  in  the  elimination  of  uric 
acid  and  the  relationship  of  total  nitrogen  to  uric-acid  nitrogen  is  found  in  v. 
Noorden's  Lehrbuch  der  Pathologie  des  Stoffwechsels,  S.  54. 

6  See  Centralbl.  f.  d.  med.  Wissensch.,  1888,   S.  2. 
«  Nord.  med.  Arkiv.,  1894,   Xo.   10. 


URIC  ACID.  473 

In  regard  to  the  action  of  food  we  know  from  the  observations 
of  Ranke,'  Makes,"  and  Camerer'  that  the  elimination  of  uric 
acid  is  diminished  in  starvation,  and  that  it  quickly  increases  on 
partaking  food,  especially  proteid  food.  Mares  found  the  mini- 
mum about  13  hours  after  the  last  meal,  and  a  strong  increase  about 
2-5  hours  after  meat  diet.  This  increase  after  a  meal  rich  in  pro- 
teid IIoRBACZEWSKi  *  explains  by  the  digestion  leucocytosis  (see 
below)  which  habitually  appears.  It  is  quite  generally  accepted 
that  the  quantity  of  uric  acid  eliminated  with  vegetable  food  is 
smaller  than  with  a  meat  diet,  in  which  case  the  quantity  may  rise 
to  2  grms.  or  over  per  24:  hours.  ^ 

The  statements  in  regard  to  the  influence  of  other  circumstances, 
as  also  of  different  bodies,  on  the  elimination  of  uric  acid  are  rather 
contradictory.  This  is  in  part  due  to  the  fact  that  the  older  inves- 
tigators used  an  inaccurate  method  (Hein^tz's  method),  and  also,  as 
shown  especially  by  Mares  and  Salkowski,'  that  the  exteht  of 
uric-acid  elimination  is  dependent  in  the  first  place  upon  the  indi- 
viduality. According  to  Schondorff  '  the  drinking  of  water,  con- 
trary to  older  statements,  does  not  have  any  effect  on  the  elimination 
of  uric  acid.  According  to  Clar  '  and  Haig  °  alkalies  increase 
the  elimination  of  uric  acid,  while  according  to  Salkowski  they 
diminish,  and  according  to  Hermann  '"  they  have  no  influence  on 
the  elimination.  Horbaczewski  and  Kanera''  found  an  increased 
elimination  of  uric  acid  after  the  administration  of  glycerin,  while 
no  increase  was  observed  after  partaking  sodium  acrylate  (Horbac- 
t^EWSKi'").  Certain  medicines,  such  as  quinin  and  atropin,  diminish, 
while  others,  such  as  pilocarpin,  increase,  the  elimination  of  uric 
acid.     According  to  Horbaczewski"  and  his  pupils  the  first  cause 

'  J.  Rauke,  Beobachtungen  und  Versuclie  tlber  die  Ausscheidung  der  Harn- 
saure,  etc.     Miinchen,  1858. 

^  L.  c. 

»  Zeitsclir.  f.  Biologie,  Bd.  26. 

♦  Wien.  Sitzungsber,,  Bd.   100,  Abth.  3,  1891. 

'  In  regard  to  tlie  action  of  various  diets  tlie  reader  is  referred  to  the  above- 
cited  authors,  and  especially  to  A.  Hermann,  Arch,  f.  klin.  Med.,  Bd.  43. 

'  Virchovv's  Arch.,  Bd.  117. 

'  Pfiilger's  Arch.,  Bd.  46. 

8  Centralbl.  f.  d.  med.  Wissensch.,  1888,  No.  25. 

9  Journal  of  Physiol.,  Vol.  8. 
'0  Arch.  f.  klin.  Med.,  Bd.  43. 
"  Wien.  Sitzungsber.,  Bd.  97. 

»«  Monatshefte  f.  Chem..  Bd.  10. 
"Wien.  Sitzungsber.,  Bd.  100. 


474  THE    URINE. 

a  diminntion  of  the  number  of  leucocytes  in  the  blood,  while  the 
last  cause  an  increase  in  the  number. 

Little  is  known  in  regard  to  the  elimination  of  uric  acid  in  dis- 
ease. The  nric  acid  introduced  into  the  organism  of  a  dog  is  in 
great  part,  as  shown  by  Frerichs  and  Wohler,'  converted  into 
urea,  and  as  nrea  is  also  formed  by  the  action  of  oxidizing  agents 
on  nric  acid  outside  of  the  body,  uric  acid  has  been  often  considered 
as  a  step  towards  the  formation  of  urea  in  the  organism.  Such  a 
view  is  not,  however,  well  founded,  and  the  statement  that  in 
diseases  with  an  incomplete  supply  of  oxygen  and  diminished  oxida- 
tion an  increased  formation  of  nric  acid  is  produced  has  not  been 
proved.  With  regard  to  the  pathological  relations  we  really  only 
know  two  conditions  in  which  the  elimination  of  uric  acid  is 
increased,  namely,  in  fever  and  leucsemia.  In  fevers  the  uric  acid 
eliminated  is  increased  after  the  crisis,  but  it  is  undecided  whether 
the  quantity  is  increased  at  the  heigh  b  of  the  fever  as  compared  to 
the  normal.^  In  leucaemia  the  elimination  is  increased  absolutely 
as  well  as  relatively  to  the  urea  (Ranke,'  Salkow^ski,'  Fleischer 
and  Pejstzoldt,'  Stadthagen,'  Sticker,'  Bohlaistd  and  Schfrz,* 
and  others),  and  the  relationship  between  the  uric  acid  and  urea 
(total  nitrogen  recalculated  as  urea)  may  be  even  1  :  9,  while  under 
normal  conditions,  according  to  different  investigators,  it  is  1  :  40  to 
66  to  100.  The  elimination  of  uric  acid  may  be  diminished  in  gout 
shortly  before  and  daring  the  attack. 

Formation  of  Uric  Acid  in  the  organism.  The  formation  of 
nric  acid  in  birds  is  increased  by  the  administration  of  ammonia- 
salts  (v.  Schroder').  Urea  acts  in  the  same  way  (Meter  and 
Jaffe"),  while  in  the  organism  of  mammalia  uric  acid  is  more  or 
less  completely  converted  into  urea.  Minkowski  "  observed  in 
geese  with  extirpated  livers  a  very  significant  decrease  in  the 
elimination  of  uric  acid,   while    the   elimination  of  ammonia  was 

1  Annal.  d.  Cbem.  u.  Pharm.,  Bd.  65. 

*  See  V.  Noorden,  Lehrbucli  d.  Pathol,  des  Stoffwechsels,  S.  211  and  312. 
3  Schmidt's  Jahrb.,  1«59. 

*  Virchow's  Arch. ,  Bd.  50. 

5  Arch.  f.  klin.  Med.,  Bd.  26. 

«  Virchow's  Arch.,  Bd.  109. 

••  Zeitschr.  f.  klin.  Med.,  Bd.  14. 

8  Pflilger's  Arch.,  Bd.  47. 

^  Zeitschr.  f.  physiol.  Chem.,  Bd.  2.  • 

'0  Ber.  d,  deutsch.  Chem.  Gesellsch.,  Bd.  10 
"  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  21. 


FORMATION  OF  URIC  ACID.  475 

increased  to  a  corresponding  degree.  This  indicates  a  participation 
of  ammonia  in  the  formation  of  uric  acid  in  the  organism  of  birds; 
and  as  Minkowski  has  also  found  after  the  extirpation  of  the  liver 
that  considerable  amounts  of  lactic  acid  occur  in  the  urine,  it  is 
probable  that  the  uric  acid  in  birds  is  produced  in  the  liver,  perhaps 
from  lactic  acid  and  ammonia  by  synthesis.  Amido-acids — leucin, 
glycocoll,  and  aspartic  acid — increase  the  elimination  of  uric  acid  in 
birds  (v.  Knieriem  '),  but  whether  the  amido-acids  are  first 
decomposed  with  the  splitting  off  of  ammonia  is  still  unknown. 
We  have  no  basis  for  the  statement  as  to  the  formation  of  uric 
acid  from  ammonium  salts  in  the  human  and  mammalian  liver. 
Y.  Mach"  has  shown  that  a  small  part  of  the  uric  acid  in  birds 
originates  from  hypoxanthin,  and  a  similar  origin  for  the  uric  acid 
of  mammalia  is  also  very  probable  (Minkowski). 

The  xanthin  bases,  as  stated  in  Chapter  V,  originate  from  the 
nncleins,  and  Horbaczewski  ^  gives  the  same  origin  for  uric 
acid.  According  to  tliis  investigator  uric  acid  is  not  derived 
from  the  naclein  with  the  xantiiin  bases  as  intermediate  steps, 
but  uric  acid  or  xanthin  bases  originate  rather  from  the  same 
mother-substance,  the  nuclein  substances,  according  to  circum- 
stances. 

Uric  acid  is  formed  when  a  cleavage  precedes  an  oxidation,  and 
xanthin  bases,  on  the  contrary,  by  cleavage  without  oxidation. 
Several  circumstances  speak  for  this  origin  of  uric  acid  in  the 
organism.  Horbaczewski  has  prepared  uric  acid  from  tissues  rich 
in  nuclein,  such  as  the  spleen-pulp,  and  from  spleen  nuclein  by 
slight  putrefaction,  subsequent  oxidation  with  blood,  and  then 
cleavage  by  boiling.  If  the  oxidation  was  neglected,  he  obtained  an 
equivalent  quantity  of  xanthin  bases.  The  nuclein  prepared  from 
the  spleen-pulp  when  introduced  into  the  animal  body  causes  an 
increase  in  the  elimination  of  uric  acid,  which  IIorbaczeavski  con- 
siders is  not  due  to  a  direct  transformation  of  the  naclein. 
According  to  him  it  may  be  due  indirectly  to  tlie  lencocytosis  pro- 
duced by  the  nuclein.  According  to  Horbaczewski  the  nric  acid 
originates  chiefly  from  the  nuclein  of  the  destroyed  leucocytes,  and 
the  greater  the  number  of  leucocytes  in  the  blood  the  greater  is 
the  destruction  of  the  same,  and  hence  the  elimination  of  uric  acid 

»  Zeitschr.  f.  Biologie,  Bd.  13. 

«  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  24. 

»  Wien  Sitzungsber.,  Bd.  100. 


476  THE   UBINE. 

is  correspondingly  increased.  Observations  on  the  elimination  of 
uric  acid  stand  in  good  accord  with  this  theory.  Thus,  for  example, 
new-born  children  eliminate  more  uric  acid  than  adnlts  because  of 
the  leucocytosis  going  on.  The  increase  in  the  elimination  of  uric 
acid  after  food  rich  in  proteid  is  explained  by  the  leacocytosis,  as 
also  the  abundant  formation  of  uric  acid,  after  animal  as  compared 
with  vegetable  food.  Leucaemia,  in  which  the  elimination  of  uric 
acid  is  greatly  increased,  is  characterized  by  an  abnormally  great 
number  of  leucocytes  in  the  blood.  Such  medicaments,  which 
increase  the  number  of  leucocytes,  also  increase  in  general '  the 
elimination  of  uric  acid. 

It  seems  positively  proven  that  a  certain  relationship  exists 
between  the  elimination  of  uric  acid  and  the  quantity  of  leucocytes 
in  the  blood,  and  Horbaczewski's  view  that  the  uric  acid  is  a 
product  of  the  destruction  of  the  leucocytes  is  very  acceptable. 
The  positive  proof  that  uric  acid  actually  originates  in  the  destruc- 
tion of  the  leucocytes  and  not  in  some  other  way,  in  their  reforma- 
tion or  as  a  metabolic  product,  has,  as  stated  by  Mares, ^  not  been 
given. 

We  cannot  say  anything  positive  in  regard  to  the  organ  or 
organs  in  which  uric  acid  is  formed. 

After  the  extirpation  of  the  kidneys  of  snakes  (Zalesky^)  and 
birds  (v.  Schroder  *)  an  accumulation  of  uric  acid  in  the  blood  and 
tissues  has  been  observed.  This  shows  that  the  kidneys  of  these 
animals  are  not  the  only  organ  producing  uric  acid,  and  any  direct 
proof  of  the  formation  of  this  acid  in  the  kidneys  has  not  to  the 
present  time  been  demonstrated.  A  direct  relationship  between  the 
spleen  and  the  formation  of  uric  acid,  also  in  man,  has  been  sought 
by  several  investigators.  According  to  the  investigations  of 
Horbaczewski  this  relationship  seems  to  be  of  an  indirect  kind,  as 
it  probably  stands  in  close  connection  with  the  importance  of  the 
spleen  to  the  formation  of  the  leucocytes.  If  uric  acid  is  derived  in 
man  and  mammals  chiefly  from  nuclein,  then  we  must  look  for  its 
formation  where  a  destruction  of  tissues  containing  nuclein  takes 
place,  although,  according  to  Horbaczewski,  it  originates  in  the 

'  Horbaczewski,  1.  c. 

'  Wien  Sitzungsber.,  Bd.  101,  Abth.  3,  and  "  Zur  Theorie  der  Harnsaure- 
bildung  im  Saugethierorganismus."    Prag,  1892. 

'  Cited  from  Hermann's  llandb.,  Bd.  5,  Thl.  1,  S.  305. 

■*  Du  Bois-Reymond's  Arch.,  1880,  Suppl.  Bd.,  and  Ludwig's  Festschrift, 
1887. 


PROPERTIES  AND  REACTIONS   OF  URIC  ACID.  477 

first  place  in  the  destruction  of  the  leucocytes.  We  have  no  posi- 
tive basis  for  the  statement  that  uric  acid  is  formed  in  the  liver  of 
man  and  mammals,  but  the  formation  of  uric  acid  in  the  liver  of 
birds  is  shown  to  be  highly  probable  by  the  researches  of  Min- 
kowski. 

Properties  and  Reactions  of  Uric  Acid.  Pure  uric  acid  is  a 
white,  odorless,  and  tasteless  powder  consisting  of  very  small  rhom- 
bical  prisms  or  plates.  Impure  uric  acid  is  easily  obtained  as  some- 
what larger,  colored  crystals. 

In  quick  crystallization,  small,  apparently  colorless,  thin,  four- 
sided  rhombic  prisms  are  formed,  which  can  only  be  seen  by  the  aid 
of  the  microscope,  and  these  sometimes  appear  as  sjdooIs  because  of 
the  rounding  of  their  obtuse  angles.  The  plates  are  sometimes  six- 
sided,  irregnlarly  developed;  in  other  cases  they  are  rectangular 
with  partly  straight  and  partly  Jagged  sides;  and  in  other  cases  they 
show  still  more  irregular  forms,  the  so-called  dumb-bells,  etc.  In 
slow  crystallization,  as  when  the  urine  deposits  a  sediment  or  when 
treated  with  acid,  large,  always  colored  crystals  separate.  Examined 
with  the  microscope  these  crystals  appear  always  yellow  or  yellowish 
brown  in  color.  The  most  ordinary  form  is  the  whetstone  shape 
formed  by  the  rounding  off  of  the  obtuse  angles  of  the  rhombic 
plate.  The  whetstones  are  generally  connected  together,  two  or 
more  crossing  each  other.  Besides  these  forms,  rosettes  of  prismatic 
crystals,  irregular  crosses,  brown-colored  rough  masses  of  destroyed 
needles  and  prisms  occur,  also  other  forms. 

Uric  acid  is  insoluble  in  alcohol  and  ether;  it  is  rather  easily 
soluble  in  boiling  glycerin,  very  difficultly  soluble  in  cold  water 
(14,000-15,000  parts),  and  difficultly  soluble  in  boiling  water  (in 
1800-1900  parts).  It  is  soluble  in  a  warm  solution  of  sodium 
diphosphate,  and  in  the  presence  of  an  excess  of  uric  acid  mono- 
phosphate and  acid  urate  are  produced.  Sodium  phosphate  is  con- 
sidered as  a  solvent  for  the  uric  acid  in  the  urine.  According  to 
KiJDEL '  urea  is  an  important  solvent.  1000  c.  c.  of  a  3^  urea 
solution  can  hold  on  an  average  0.529  grm.  uric  acid  in  solution, 
and  as  the  daily  quantity  of  urine  is  1500-2000  c.  c,  and  this  con- 
tains 2^  urea,  it  is  possible  for  the  urea  alone  to  hold  nearly  all  of 
the  uric  acid  eliminated  in  solution.  Piperazin  (diethylendiamin), 
C^Hj^Nj,  is  also  a  good  solvent  for  uric  acid.     Uric  acid  dissolves 

1  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  30. 


4Y8  THE    URINE. 

without  decomposing  in  concentrated  sulphuric  acid.  It  is  com- 
pletely precipitated  from  the  urine  by  picric  acid  (Jaffe  '). 

Uric  acid  is  dibasic  and  correspondingly  forms  two  series  of 
salts,  neutral  and  acid.  According  to  Bence  Jones'*  hyperacid 
salts,  QUADRiURATES,  With  the  general  formula  (MHU  +  HjU)  also 
occur. 

Of  the  alkali  urates  the  neutral  potassium  and  lithium  salts  dis- 
solve most  easily,  and  the  ammonium  salt  dissolves  with  difficalty. 
The  acid-alkali  urates  are  very  insoluble,  and  separate  as  a  sediment 
(sedimentum  lateritium)  from  concentrated  urine  on  cooling.  The 
salts  with  alkaline  earths  are  very  insoluble. 

If  a  little  uric  acid  in  substance  is  treated  on  a  porcelain  dish 
with  a  few  drops  of  nitric  acid,  tlie  uric  acid  dissolves  on  warming 
with  a  strong  development  of  gas,  and  after  thoroughly  drying  on 
the  water-bath  a  beautiful  red  residue  is  obtained,  which  turns  a 
purple-red  (ammonium  purpurate  or  murexide)  on  the  addition  of 
a  little  ammonia.  If,  instead  of  the  ammonia,  we  add  a  little 
caustic  soda  (after  cooling),  the  color  becomes  more  blue  or  bluish 
violet.  This  color  disappears  quickly  on  warming,  differing  from 
certain  xanthin  bodies.  This  reaction  is  called  the  murexide 
test. 

If  uric  acid  is  converted  into  alloxan  by  the  careful  action  of 
nitric  acid  and  the  excess  of  acid  carefully  expelled  on  treating  this 
with  a  few  drops  concentrated  sulphuric  acid  and  commercial  benzol 
(containing  thiophen),  a  beautiful  blue  coloration  is  obtained 
(Deniges'  '  reaction). 

Uric  acid  does  not  reduce  an  alkaline  solution  of  bismuth,  but 
does,  on  the  contrary,  an  alkaline  copper-hydroxide  solution.  In 
the  presence  of  only  a  little  copper  salt  we  obtain  a  white  precipitate 
consisting  of  copper  urate.  In  the  presence  of  more  copper  salt  red 
suboxide  separates.  The  method  for  the  volumetric  estimation  of 
uric  acid  as  suggested  by  Arthaud  and  Butte,'  as  well  as  the 
method  suggested  by  Kruger  and  Wulff,"  is  based  on  the  insolu- 
bility of  copper  urate. 

'  Zeitscbr.  f,  pUysiol.  Chem.,  BJ.  10. 

*  Journ.  Chem.  Soc,  1862,  vol,  xv.,  p.  8. 

»  Journal  de  Pliarm.  et  de  Chim.,  Tome  18.      Cited  from  Maly's  Jahresber., 
Bd.  18.  S   24. 

*  Compt.  rend.  soc.  biol.,  Tome  41.  Cited  from  Maly's  Jahresber.,  Bd.  20, 
S.  180 

<•  Zeitscbr.  f.  physiol.  Chem..  Bd.  20. 


ESTIMATION  OF  URIC  ACID.  479 

If  a  drop  of  nric  acid  dissolved  in  sodium  carbonate  is  placed  on 
a  piece  of  filter-paper  which  has  been  previously  treated  with  silver- 
nitrate  solution,  a  reduction  of  silver  oxide  occurs  producing  a 
brownish-black  or,  in  the  presence  of  only  0.003  milligramme  uric 
acid,  a  yellow  spot  (Schiff's  '  test). 

Preparation  of  Uric  Acid  from  Urine.  Filtered  normal  urine 
is  treated  with  20-30  c.  c.  of  25^  hydrochloric  acid  for  each  litre  of 
urine.  After  forty-eight  hours  collect  the  crystals  and  pnrify  them 
by  redissolving  in  dilute  alkali,  decolorizing  with  animal  charcoal 
and  repreci  pita  ting  with  hydrochloric  acid.  Large  quantities  of 
uric  acid  are  easily  obtained  from  the  excrements  of  serpents  by 
boiling  them  with  dilute  caustic  potash  until  no  more  ammonia  is 
developed.  A  current  of  carbon  dioxide  is  passed  through  the 
filtrate  until  it  barely  has  an  alkaline  reaction;  dissolve  the  separated 
and  washed  acid  potassium  urate  in  caustic  potash,  and  precipitate 
the  uric  acid  by  addition  of  an  excess  of  hydrochloric  acid  to  the 
filtrate. 

Quantitative  Estimation  of  Uric  Acid  in  the  urine.  As  the 
older  method  as  suggested  by  Heintz,  even  after  recent  modifica- 
tions, gives  inaccurate  results,  we  will  not  give  it  in  detail. 

Salkowski  ^  and  Ludwig's  *  method  consists  in  precipitating 
by  silver  nitrate  the  uric  acid  from  the  urine  previously  treated 
with  magnesia-mixture,  and  weighing  the  uric  acid  obtained  from 
the  silver  precipitate.  Uric-acid  determinations  by  this  method 
are  often  performed  according  to  the  suggestion  of  E.  Ludwig, 
which  requires  the  following  solutions: 

1.  An  AMMONIACAL  SILVER-NTTRATE  solution,  wbicli  Contains  in  one  litre 
26  grnis.  silver  nitrate  and  a  quantity  of  ammonia  sufficient  to  completely  re- 
dissolve  the  precipitate  produced  by  the  first  adilition  of  ammonia.  2.  Mag- 
nesia MIXTURE.  Dissolve  100  grms.  crystallized  magnesium  chloride  in  water 
and  add  enough  ammonia  so  that  the  liquid  smells  strong!}'  of  it,  and 
enough  ammonium  chloride  to  dissolve  the  precipitate  and  dilute  to  1  litre. 
H.  Sodium-sulphide  solution.  Dissolve  10  grms.  caustic  soda  whicU  is 
free  from  nitric  acid  and  nitrous  acid  in  1  litre  of  water.  One  half  of  this 
solution  is  completely  saturated  with  sulphuretted  Lydrogen  and  then  mixed 
with  the  other  half. 

The  concentration  of  the  three  solutions  is  so  arranged  that  10 
c.  c.  of  each  is  sufficient  for  100  c.  c.  of  the  urine. 

100-200  c.  c,  according  to  concentration,  of  the  filtered  urine 
freed  from  proteid  (by  lioiling  after  the  addition  of  a  few  drops  of 
acetic  acid)  are  poured  into  a  beaker.  In  another  vessel  mix  10-20 
c.  c.  of  the  silver  solution  with  10-20  c.  c.  of  the  magnesia  mixture 
and  add  ammonia,  and  when  necessary  also  some  ammonium 
chloride,  until  the  mixture  is  clear.     This  solution  is  added  to  the 

•  Annal.  d   Chem.  u.  Pharra.,  Bd.  109. 

'  Virchow's  Arch.,  Bd.  52,  and  Pli tiger's  Arch.,  Bd.  5. 

»  Wien.  med.  Jahrb.,  1884,  and  Zeitschr.  f.  analyt.  Chem.,  Bd.  24. 


480  THE   URINE. 

urine  while  stirring,  and  the  mixture  allowed  to  stand  quietly  for 
half  an  hoar.  The  precipitate  is  collected  on  a  filter,  washed  with 
ammoniacal  water,  and  then  returned  to  the  same  beaker  by  the  aid 
of  a  glass  rod  and  a  spirt-bottle,  without  destroying  the  filter,  Now 
heat  to  boiling  10-20  c.  c.  of  the  alkali-sulphide  solution,  which 
has  previously  been  diluted  with  an  equal  volume  of  water,  and 
allow  this  solution  to  flow  through  the  above  filter  into  the  beaker 
containing  the  silver  precipitate,  wash  with  boiling  water,  and  warm 
the  contents  of  the  beaker  on  a  water-bath  for  a  time,  stirring  con- 
stantly. After  cooling  filter  into  a  porcelain  dish,  wash  with  boil- 
ing water,  acidify  the  filtrate  with  hydrochloric  acid,  evaporate  to 
about  15  c.  c,  add  a  few  drops  more  of  hydrochloric  acid,  and  allow 
it  to  stand  for  24  hours.  The  uric  acid  which  has  crystallized  is 
collected  on  a  small  weighed  filter,  washed  with  water,  alcohol, 
ether,  and  carbon  disulphide,  dried  at  100-110°  C.  and  weighed. 
For  each  10  c.  c.  of  watery  filtrate  we  must  add  0.00048  grm.  uric 
acid  to  the  quantity  found  directly.  Instead  of  the  weighed  filter- 
paper  a  glass  tube  filled  with  glass-wool  as  described  in  other  hand- 
books may  be  substituted  (Ludwig).  Too  strong  or  continuous 
heating  with  the  alkali  sulphide  must  be  prevented,  otherAvise  a 
part  of  the  uric  acid  may  be  decomposed.  Gkove  '  recommends  a 
solution  of  potassium  iodide  instead  of  the  alkali  sulphide,  thus 
making  the  washing  with  carbon  disulphide  unnecessary.  Camerek  ■' 
has  modified  this  method  in  certain  points,  and  he  determines  the 
nitrogen  in  the  silver  precipitate  (a-uric  acid  =  uric  acid  contami- 
nated with  xanthin  bodies)  and  also  the  uric  acid  isolated  by  Sal- 
kowski-Ludwig's  method  (=  b-uric  acid). 

Haycraft's  Method.^  25  c.  c.  of  the  urine  are  first  treated 
with  1  grm.  bicarbonate,  then  made  strongly  alkaline  by  ammonia, 
and  lastly  precipitated  by  an  ammoniacal  silver  solution.  The 
carefully  washed  precipitate  is  dissolved  in  20-30^  nitric  acid  and 

AT 

this  solution  titrated  with  a  — -r  sulphocyanide  solution  according 

to  Volhard's  method.  Each  c.  c.  of  this  solution  corresponds  to 
0.00168  grm.  uric  acid.  This  method  has  been  modified  in  certain 
points  by  Hermann  '  and  Czapek,^  which  last  titrates  with  alkali 
sulphide  the  silver  salts  remaining  in  solntion  in  the  urine  after  the 
precipitation  of  the  uric  acid  by  a  known  volume  of  ammoniacal 
silver  solution  of  known  strength.  The  advantage  of  Haycraft's 
method  is  the  ease  and  rapidity  with  which  it  can  be  performed, 
and  it  is  therefore  recommended  for  clinical  purposes.     For  exact 

1  Journ.  of  Physiol.,  Bd.  12. 

2  Zeitschr.  f.  Biologie,  Bdd.  27  u.  28. 

3  Zeitschr.  f    analyt.  Cheui.,  Bd.  25. 
*Z  itschr.  f.  physiol.  Chem.,  Bd.  12. 
«  i6«a. ,  Bd.  12,  S.  502. 


OXALIC  ACID.  481 

determinations  it  is  not  quite  reliable,  because  the  amount  of  silver 
in  the  precipitate  of  silver  urate  is  not  constant  (Salkowski  '). 
Hatcraft's  method  gives  the  same  results  as  8alkowski-Lud- 
wig's  method  in  pure  uric-acid  solutions.  With  the  urine 
Hatcraft's  method  gives  on  the  contrary  too  high  results,  which 
is  in  part  due  to  the  fact  that  the  silver  solution  precipitates  from 
the  urine  other  bodies,  such  as  xanthin  bases,  besides  the  uric  acid. 
Since  the  value  of  this  method  has  been  the  subject  of  much 
adverse  criticism,  we  will  not  give  further  particulars." 

In  regard  to  Fokker's  '  method  we  refer  the  reader  to  more 
exhaustive  text-books. 

Hopkins's  '  method  is  based  on  the  fact  that  the  uric  acid  is 
completely  precipitated  from  the  urine  as  ammonium  urate  on 
saturating  with  ammonium  chloride.  The  urine  is  saturated  with 
ammonium  chloride  (for  each  100  c.  c.  urine  add  30  grms. 
ammonium  chloride)  and  filter  after  two  hours.  Wash  with  a 
saturated  solution  of  ammonium  chloride,  and  transfer  the  precipi- 
tate from  filter  to  a  small  beaker  by  means  of  boiling  water,  and 
decomjiose  ib  with  hydrochloric  acid  and  heat.  The  uric  acid  which 
separates  is  determined  by  weighing  it  as  such,  or  by  titration  with 
potassium  permanganate.  This  simple  method  gives  as  good  results 
as  Salkowski-Ludwig's  method.  Kruger  and  Wulff's  method 
will  be  treated  of  in  connection  with  xanthin  bases  in  the  urine. 

OxALURic  Acid,  CH^N^O,  =  (CON5H3)  CO.COOH.  This  acid,  whose  rela- 
tion to  uric  acid  and  urea  has  been  spoken  of  above,  occurs  only  as  traces  in 
the  urine  as  ammonium  salts.  This  salt  is  not  directly  precipitated  by  CaCIj 
and  NH3  ,  but  after  boiling,  when  it  is  decomposed  into  urea  and  oxalate.  In 
preparing  oxaluric  acid  from  urine  the  latter  is  filtered  through  animal  char- 
coal. The  oxalurate  retained  by  the  charcoal  may  be  obtained  by  boiling  with 
alcohol. 

POOTT 
Oxalic  Acid,   C,H,0„   or  pz-wy^-rr*    occurs   under  physiological 

conditions  in  very  small  amounts  in  the  urine,  about  0.02  grm.  in 
24  hours  (Furbringer  ").  According  to  the  generally  accepted 
view  it  exists  in  the  urine  as  calcium  oxalate,  which  is  kept  in  solu- 

'  Pflilger's  Arch.,  Bd.  5;  also  Salskowski  and  Jolin,  Zeitschr.  f.  physiol. 
Chem.,  Bd.  14. 

'•  In  regard  to  the  literature  on  this  subject  see  Huppert-Neubauer's  Harn- 
analyse.  See  also  Lisowski,  Maly's  Jahresber.,  Bd.  20;  Deroide,  ibid.,  Bd.  21, 
S.  172,  Groves,  1,  c. ;  and  Haycraft,  Zeitschr,  f.  physiol.  Chem.,  Bd.  15. 

»  Pflilger's  Arch.,  Bd.  10. 

*  Journal  of  Pathology  and  Bacteriology,  1893,  and  Proceedings  of  Royal 
Society,  Vol.  52. 

»  Deutsch.  Arch.  f.  klin.  Med.,  Bd.  18. 


482  -  THE   URINE. 

tion  by  the  acid  phosphates  present.  Calcium  oxalate  is  a  frequent 
constituent  of  urinary  sediments,  and  occurs  also  in  certain  urinary 
calculi. 

The  origin  of  the  oxalic  acid  in  the  urine  is  not  well  known. 
Oxalic  acid  when  administered  is  eliminated,  at  least  in  part,  by 
the  "urine  unchanged,  and  as  many  vegetables  and  fruits,  such  as 
cabbage,  spinach,  asparagus,  sorrel,  apples,  grapes,  etc.,  contain 
oxalic  acid,  it  is  possible  that  a  part  of  the  oxalic  acid  of  the  urine 
originates  directly  from  the  food.  According  to  Abeles  '  this  is 
not  the  case.  According  to  him  an  alimentary  oxaluria,  that  is,  an 
elimination  of  oxalic  acid  caused  by  partaking  of  the  ordinary  foods 
containing  oxalic  acid,  does  not  exist,  and  the  soluble  oxalates  of  the 
food  are  in  all  probability  converted  into  insoluble  lime-salts  in  the 
digestive  tract.  That  oxalic  acid  may  be  formed  in  the  animal  body 
from  proteid  or  fat  follows  from  the  observations  of  Mills  ^  that 
oxalic  acid  is  found  in  the  urine  of  dogs  after  feeding  with  meat 
and  fat  alone.  Oxalic  acid  is  also  supposed  to  be  derived  by  the 
incomplete  combustion  of  carbohydrates,  and  is  also  considered,  but 
not  with  sufficient  basis,  as  an  oxidation  product  of  uric  acid. 

An  increased  elimination  of  oxalic  acid  may  occur  in  diabetes. 
The  question  whether  it  occurs  as  an  independent  disease  {oxaluria, 
oxalic-acid  diathesis)  has  not  been  positively  decided. 

The  properties  and  reactions  of  oxalic  acid  and  calcium  oxalate 
are  well  known.     Calcium  oxalate  as  a  constituent  of  urinary  sedi 
ments  will  be  described  later. 

Detection  and  Quantitative  Estimation  of  Oxalic  Acid  in  Urine. 
The  presence  of  oxalic  acid  in  solution  in  urine  is  determined 
according  to'  the  method  suggested  by  Neubauer,'  who  treats 
500-600  c.  c.  of  the  urine  with  CaCl^  solution,  makes  alkaline  with 
ammonia  and  then  faintly  acid  with  acetic  acid.  After  24  hours 
the  precipitate  is  collected  on  a  small  filter,  washed  with  water, 
treated  with  hydrochloric  acid  (which  leaves  the  uric  acid  undis- 
solved on  the  filter),  and  washed  again  with  water.  The  filtrate, 
including  the  wash-water,  is  treated  with  an  excess  of  ammonia  and 
allowed  to  stand  24  hours.  Calcium  oxalate  separates  as  quadratic 
octahedra.  The  quantitative  estimation  is  performed  after  the  same 
principle.  The  oxalate  is  converted  into  quicklime  by  heat,  and 
weighed  as  such. 

•  Wien.  klin.  Wocbensclir. ,  1893. 

2  Vircbow's  Arch.,  Bd.  91. 

3  ZeitHchr.  f.  analyt.  Chem.,  Bd.  8,  S.  521. 


ALLANTOm.  483 

AUantoin  or  glyoxyldiureid,  C^H^N^O,  or 

^^/NH.CH.NH.CO.NH,  .     ^,         .        ,    ,.,, 

\j(j<  „„  p^  ,  occurs  m  the  urme  of  children  withm 

the  first  eight  days  after  birth,  and  in  very  small  amounts  also  in 
the  urine  of  adults  (Gusserow,'  Ziegler  and  Hermann').  It  is 
lonnd  in  rather  abundant  quantities  in  the  urine  of  pregnant 
women  (Gusserow),  AUantoin  has  also  been  found  in  the  urine 
of  sucking  calves  (Wohler'),  and  sometimes  in  the  urine  of  other 
animals  (Meissner*).  It  is  also  found  in  the  amniotic  fluid  and, 
as  first  shown  by  Vauquelin  '  and  Lassaigne,°  in  the  allantoic 
fluid  of  the  cow  (hence  the  name),  AUantoin  is  formed,  as  above 
stated,  by  the  oxidation  of  uric  acid.  The  increased  elimination  of 
allantoin  which  Salkowski  '  observed  in  dogs  after  the  administra- 
tion of  uric  acid  shows  that  the  formation  of  allantoin  from  uric 
acid  in  the  organism  is  not  improbable.  Borissow  *  has  observed 
an  abundant  elimination  of  allantoin  in  dogs  after  poisoning  with 
diamid. 

Allantoin  is  a  colorless  substance  often  crystallizing  in  prisms, 
difficultly  soluble  in  cold  water,  easily  soluble  in  boiling  water  and 
also  in  warm  alcohol,  but  not  soluble  in  cold  alcohol  or  ether.  It 
combines  with  acids,  forming  salts.  A  watery  allantoin  solution 
gives  no  precipitate  with  silver  nitrate  alone,  but  by  the  careful 
addition  of  ammonia  a  white  floccnlent  precipitate  is  formed, 
C^H^AgN^O,,  which  is  soluble  in  an  excess  of  ammonia  and  which 
consists  after  a  certain  time  of  very  small,  transparent  microscopic 
globules.  The  dried  precipitate  contains  40.75^  silver,  A  watery 
allantoin  solution  is  precipitated  by  mercuric  nitrate.  On  contin- 
uous boiling  allantoin  reduces  Fehling's  solution.  It  gives 
Schiff's  f urfurol  reaction  less  rapidly  and  less  intensely  than  urea. 
Allantoin  does  not  give  the  murexid  test, 

Allantoin  is  most  easily  prepared  by  the  oxidation  of  uric  acid 
with  lead  peroxide.     In   preparing   allantoin  from  calves'  urine, 

I  Arch.  f.  GynakoL,  Bd.  3. 
'  See  Gusserow,  ibid. 

*  Naclir.  d.  k.  Gesellsch.  d.  Wissenscli.  zu  Qottingen,  1849.      Cited   from 
Hoppe-Seyler's  Physiol.  Cbein.,  S.  816. 

*  Zeitschr.  f.  rat.  Med.  (3),  Bd.  31. 
»  Annal.  d.  Chem.,  Bd,  33. 

*  Annal.  de  cliim.  et  de  phys.,  Tome  17. 

"*  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  9, 

*  Zeitschr.  f.  physiol.  Chem.,  Bd.  19. 


4:84:  THE    URINE. 

concentrate  the  urine  on  the  water-bath  to  a  syrup  and  allow  it  to 
stand  in  the  cold  for  several  days.  The  crystals  which  are  separated 
from  the  precipitate  by  washing  are  dissolved  in  boiling  water  with 
the  addition  of  some  animal  charcoal,  and  filtered  while  hot;  then 
acidify  the  filtrate  faintly  with  hydrochloric  acid  (so  as  to  keep  the 
phosphates  in  solution)  and  allow  it  to  crystallize.  Allantoin  is 
detected  in  human  urine  by  the  method  first  suggested  by  Meiss- 
NER,'  It  consists  chiefly  of  the  following  points:  Precipitate  the 
urine  with  baryta-water,  filter,  remove  the  baryta  with  sulphuric 
acid,  filter,  precipitate  the  allantoin  with  HgCl^  in  alkaline  solution, 
decompose  the  precipitate  with  sulphuretted  hydrogen,  concentrate 
strongly,  purify  the  crystals  which  separate  by  recrystallization,  and 
lastly  prepare  the  silver  combination. 

Xanthin  Bases.  The  xanthin  bases  which  habitually  occur  in 
human  urine  are  xanthin,  liypoxantliin  (Salomon^),  guanin 
(Pouchet"),  carotin  (Polx'het),  paraxanthin  (Thudichum,* 
Salomon"),  lieteroxantMn  (Salomon"  °),  and  episarkin  (Balke '). 
The  quantity  of  these  bodies  in  the  urine  is  very  small.  The 
quantity  of  xanthin  bodies  in  the  urine  is  increased  especially  in 
leuceemia,  in  which  disease  ade^iin  is  also  found  in  the  urine  (Stadt- 
hagen®).  An  increased  elimination  of  certain  xanthin  bases  has 
also  been  observed  by  Pouchet  in  fevers  and  affections  of  the 
nervous  system.  Kkuger  '  has  found  two  new  xanthin  bases  in 
the  urine  of  lunatics.  One  of  these,  epiguanin,  is  similar  to  guanin 
in  solubilities  and  has  the  formula  C^^H^gNgO,.  The  second  could 
not  be  obtained  in  sufficient  quantity  for  analysis.  Xanthin  also 
occurs  as  a  constituent  of  a  variety  of  rare  calculi  (Marcet).  It  is 
also  sometimes  found  as  a  constituent  of  urinary  sediments  (Bence 
Jones)  . 

Paraxanthin,    C7H8N4O2   (dimettylxantliin),    and  heteroxanthin,  C6H9N4O2 
(methyixanthin),  do  not  give  the  xanthin  reaction  with  nitric  acid  and  alkali, 

*  Zeitschr.  f,  rat.  Med.,  Bd.  31. 

^  Reichert's   and   Du   Bois-Reymond's   Arch.,    1876;      Du   Bois-Reymond's 
Arch.,  1882;  and  Zeitschr.  f.  physiol.  Chem.,  Bd.  11. 

*  Contributions  a  la  connaissance  des  matidres  extractives  de  I'urine.  Thfese, 
Paris,  1880.     Cited  from  Huppert-Neubauer. 

*  Grundzuge  d.  anat.  und  klin.  Chem.     Berlin,  1886. 

^  Du  Bois-Reymond's  Arch.,  1882;  Ber.   d.  deutsch.  chem.  Gesellsch.,  Bdd, 
16  and  18. 

*  Du  Bois-Reymond's  Arch.,  1885;  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd. 
18,  and  Zeitschr.  f.  physiol.  Chem.,  Bd.  11. 

"'  Zur  Kenntniss  der  Xanthinkorper.     Inaug.-Diss.    Leipzig,  1893. 

8  Virchow's  Arch.,  Bd.  109. 

'  Du  Bois-Reymond's  Arch.,  1894. 


XANTIIIN  BASES  AND  HIPPURIC  ACID.  485 

but  give  Weidel's  redaction  (see  page  105).  They  differ  from  other  xanthin 
bodies  by  forming  cry  Si  alline  combinations  with  alkalies  which  are  difficultly 
soluble.  Amorphous  heteroxauthin  separates  on  neutralizing  the  sodium  com- 
bination, but  paraxanthin,  on  the  contrary,  separates  in  acrystalline  condition. 
Paraxanthin  gives  an  easily  soluble  combination  with  hydrochloric  acid,  while 
heteroxauthin  forms  an  insoluljle,  beautiful  crystalline  combination. 

Episarkin  is  the  name  given  by  Balke  to  a  new  xanthin  base  occurring  in 
human  urine.  The  same  body  has  been  observed  by  Salomon  '  in  pig's  and 
dog's  urine,  as  well  as  in  urine  in  leucaemia.  Balke  gives  C4H6N3O  as  the 
probable  formula  for  episarkin.  It  is  nearly  insoluble  in  cold  water,  dissolves 
with  difficulty  in  hot  water,  but  may  be  ol)tained  therefrom  as  lonu-  fine 
needles.  Episarkin  does  not  give  the  xanthin  reaction  with  nitric  acid  nor 
Weidel's  reaction.  It  gives,  on  the  contrary,  the  murexid  test  with  hydro- 
chloric acid  and  potassium  chlorate.  The  silver  combination  is  difficultly 
soluble  in  nitric  acid. 

In  preparing  xanthin  bodies  from  the  urine,  it  is  supersaturated  with  am- 
monia and  precipitated  by  a  silver-nitrate  solution.  The  precipitate  is  then 
decomposed  with  sulphuretted  hydrogen.  The  boiling- hot  filtrate  is  evap- 
orated to  dryness  and  the  dried  residue  treated  with  3^  sulphuric  acid.  The 
xanthin  bodies  are  dissolved,  while  the  uric  acid  remains  undissolved.  This 
filtrate  is  saturated  with  ammonia  and  precipitated  by  silver-nitrate  solution. 
The  different  xanthin  bodies  may  be  separated  from  each  other  by  treating  the 
silver  precipitate  with  boiling-hot  nitric  acid  of  a  sp.  gr.  of  1.1  (see  page  108). 

The  xanthin  bases  may  be  quantitatively  estimated  according  to  the  follow- 
ing method  as  suggested  by  Kkliger  and  Wulff.'  This  method  is  based  on 
the  property  of  the  xantliin  bases  and  uric  acid  of  being  completely  jjrecip- 
itated  as  an  insoluble  copper-oxide  combination  on  the  addition  of  copper-sul- 
phate and  sodium-bisulphite  solution. 

The  author  uses  a  IBje  copper-sulphate  solution,  a  50$?  bisulphite  solution, 
and  a  \Q%  BaC'lj  solution.  The  addition  of  BaClj  has  the  purpose  of  facilitating 
the  settling  and  filtration  of  the  precipitated  cc^pper  oxide  combination  by  the 
BaSOi  foi'med.  100  c.  c.  of  the  urine,  free  irom  proteid,  is  heated  to  boiling, 
10  c.  c  of  the  bisulphite  solution  adiled  and  immediately  thereupon  10  c.  c.  of 
the  copper-sulphate  solution,  and  again  heated  to  boiling.  Then  add  5  c.  c. 
BaCl2  solution  and  allow  to  settle  for  two  hours,  filtrr  and  wash  completely 
with  boiled  wnter  which  has  been  cooled  to  60"  C.  The  filter  and  contents  are 
treated  according  to  Kjeldahl  Gunning  and  the  nitrogen  determined.  This 
nitrogen  is  the  total  nitrogen,  of  the  uric  acid  and  xanthin  bases.  If  the  nitro- 
gen of  the  uric  acid  precipitated  according  to  Salkowski-Ludwig's  method  is 
determined  in  another  portion  of  the  urine,  then  the  difference  between  these 
two  results  gives  the  nitrogen  of  the  xanthin  bases.  This  multiplied  by  2.755 
gives  the  total  quantity  of  xanthin  bases. 

If  uric  acid  is  to  be  determined  by  this  method,  the  copper-oxide  precipitate 
is  treated  with  sodium  sulphide,  filtered,  acidified  with  hydrochloric  acid,  con- 
centrated by  evaporation,  and  the  precipitati-d  uric  acid  collected  on  a  filter 
after  a  certain  time.  We  refer  the  reader  to  the  original  article  in  regard  to 
the  method  of  estimating  uric  acid  and  xanthin  bases  as  suggested  by  Sal- 
KOWSKI.* 

Hippuric  acid,  or  benzoyl-amido-acetic  acid,  CgH^NO,  or 
CgH^.CO.NH.CH^.COOH.  This  acid  decomposes  into  benzoic  acid 
.and  glycocoll  on  boiling  the  nrine  with  mineral  acids  or  alkalies, 
and  also  by  putrefaction.  The  reverse  of  this  occurs  if  these  two 
oomponents  are  lieated  in  a  sealed  tube  according  to  the  following 

'  Zeitschr.  f.  physiol.  Chem.,  Bd.  18. 

5  Ihid  ,  Bd.  20. 

3  Centralbl.  f.  d.  med.  Wissensch.,  1894,  No.  30. 


486  TEE   URINE. 

equation:  C,H,COOH  +  NH,.CH,.COOH  =  C,H,.CO.NH.CH,. 
COOH  +  H^O.  This  acid  may  be  synthetically  prepared  from 
benzamid  and  monoclilor-acetic  acid,  C^H^.CO.NH^-f  CH3CLCOOH 
=  C,H,.CO.NH.CH,.COOH  +  HCl,  also  in  other  different  ways. 

Hippuric  acid  occurs  in  large  amounts  in  the  urine  of  herbivora, 
bat  only  in  small  quantities  in  that  of  carnivora.  The  quantity  of 
hippuric  acid  eliminated  in  human  urine  on  a  mixed  diet  is  usually 
less  than  1  grm.  per  24  hours;  as  an  average  it  is  0.7  grm.  After 
eating  freely  of  vegetables  and  fruit,  especially  such  fruit  as  plums, 
the  quantity  may  be  more  than  2  grms.  Hippuric  acid  is  also 
found  in  the  perspiration,  blood,  suprarenal  capsule  of  oxen,  and  in 
ichthyosis  scales.  Nothing  is  positively  known  in  regard  to  the 
quantity  of  hippuric  acid  in  the  urine  in  disease. 

The  Formation  of  Hippuric  Acid  in  the  organism.  Benzoic 
acid  and  also  the  substituted  benzoic  acids  are  converted  into 
hippuric  acid  aud  substituted  hippuric  acids  within  the  body.  Also, 
those  bodies  are  transformed  into  hippuric  acid  which  by  oxidation 
(toluol,  cinnamic  acid,  hydrocinnamic  acid)  or  by  reduction  (quinic 
acid)  are  converted  into  benzoic  acid.  The  question  of  the  origin 
of  hippuric  acid  is  therefore  connected  with  the  question  of  the 
origin  of  benzoic  acid;  for  the  formation  of  the  second  component, 
glcyocoll,  from  the  protein  substances  in  the  body  is  without  ques- 
tiou. 

Hippuric  acid  is  found  in  the  urine  of  starving  dogs  (Sal- 
KOWSKi'),  also  in  dog's  urine  after  a  diet  consisting  entirely  of 
meat  (Meissister  and  Shepaed,'  Salkowski,  and  others).  It  is 
evident  that  the  benzoic  acid  originates  in  these  cases  from  the 
proteids.  Benzoic  acid  may  indeed  be  produced  outside  of  the 
body  by  the  oxidation  of  proteids;  the  benzoic  acid  produced  on 
a  diet  consisting  entirely  of  meat  seems  to  be  derived  from  t4ie 
putrefaction  of  the  proteids  in  the  intestine.  Among  the  products 
of  the  putrefaction  of  proteid  outside  of  the  body  Salkowski  '  has 
found  phenylpropionic  acid,  CJI,.CH,.CH,.COOH,  which  is  oxi- 
dized in  the  organism  to  benzoic  acid  and  eliminated  as  hippuric 
acid  after  combining  with  glycocoll.  Phenylpropionic  acid  seems 
to  be  formed  from  the  amidophenylpropionic  acid,  which  is  prepared 

'  Ber.  d.  deutscli.  chem.  Gesellsch.,  Bd.  11. 

'  Untersucli.  ilber  das  Entsteben  der  Hippursaure  im  thierischen  Organ- 
ismus.     Hannover,  1866, 

»  E.  and  H.  Salkowski,  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  12. 


HipprRTC  Arm.  487 

only  from  the  plant  proteids,  and  the  supposition  that  the  phenyl- 
propionic  acid  is  produced  from  tyrosin  by  putrefaction  in  the 
intestine  has  not  been  substantiated  by  the  researches  of  Bau- 
MANN,'  ScHOTTEisr/  and  Baas.'  The  importance  of  putrefaction 
in  the  intestine  in  producing  hippuric  acid  is  evident  from  the  fact 
that  after  thoroughly  disinfecting  the  intestine  of  dogs  with  calomel 
the  hippuric  acid  disappears  from  the  urine  (Baumann  *). 

The  large  quantity  of  hippuric  acid  present  in  the  urine  of 
herbivora  is  partly  explained  by  the  fact  that  vegetable  proteids 
yield  perhaps  larger  amounts  of  amidophenylpropionic  acid,  and 
partly  by  the  specially  active  processes  of  putrefaction  going  on  in 
the  intestine  of  herbivora.  These  circumstances  do  not  entirely 
explain  this  excess  of  hippuric  acid.  The  abundant  elimination  of 
hippuric  acid  by  herbivora  may  in  part  depend  on  the  great  amount 
of  aromatic  substances  in  the  food  of  these  animals  which  is  con- 
verted into  benzoic  acid  in  the  organism.  There  is  hardly  any 
doubt  that  the  hippuric  acid  in  human  urine  after  a  mixed  diet, 
and  especially  after  a  diet  of  vegetables  and  fruits,  has  in  part  a 
similar  origin. 

The  kidneys  may  be  considered  in  dogs  as  special  organs  for  th*e 
synthesis  of  hippuric  acid  (Schmiedeberg  and  Bunge  ').  In  other 
animals,  as  in  rabbits,  the  formation  of  hippuric  acid  seems  to  take 
place  in  other  organs,  such  as  the  liver  and  muscles.  The  synthesis 
of  hippuric  acid  is  therefore  not  exclusively  limited  to  any  special 
organ,  though  perhaps  in  some  species  of  animals  it  may  be  more 
abundant  in  one  organ  than  in  another. 

Properties  and  reactions  of  hippuric  acid.  This  acid  crystallizes 
in  semi-transparent,  milk-white,  long,  four-sided  rhombic  prisms  or 
columns,  or  in  needles  by  rapid  crystallization.  They  dissolve  in 
600  parts  cold  water,  but  more  easily  in  hot  water.  They  are  easily 
solnble  in  alcohol,  but  with  difficulty  in  ether.  They  are  more 
easily  solnble  (about  12  times)  in  acetic  ether  than  in  ethyl  ether. 
Petroleum  ether  does  not  dissolve  them. 

On  heating  hippuric  acid  it  first  melts  at  187.5°  C.  to  an  oily 
liquid  which  crystallizes  on  cooling.     By  continuing  the  heat  it 

'  Zeitscbr.  f.  physiol.  Chem.,  Bd.  7. 
'Ubid.,  Bd.  8. 
^  Ibid.,  Bd.  11. 
*  Ibid.,    Bd.  10,  S.  131. 

■•  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  6.  Also  Ar.  Hoffmann,  ibid.,  Bd.  7, 
and  Kochs,  Pfliiger's  Arch.,  Bd.  20. 


48 S  THE   URINE. 

decomposes,  producing  a  red  mass  and  a  sublimate  of  benzoic  acid, 
-with  the  generation,  first,  of  a  peculiar  pleasant  odor  of  liay,  and 
then  an  odor  of  hydrocyanic  acid.  Hippuric  acid  is  easily  differen- 
tiated from  benzoic  acid  by  this  behavior,  also  by  its  crystalline 
form  and  its  insolubility  in  petroleum  ether.  Hippuric  acid  and 
'benzoic  acid  both  give  Lucke's  reaction,  namely,  they  generate  an 
intense  odor  of  nitrobenzol  when  evaporated  with  nitric  acid  to 
dryness  and  when  the  residue  is  heated.  Hippuric  acid  forms 
crystallizable  salts,  in  most  cases,  with  bases.  The  combinations 
with  alkalies  and  alkaline  earths  are  soluble  in  water  and  alcohol. 
The  silver,  copper,  and  lead  salts  are  soluble  with  difficulty  in 
water;  the  iron-oxide  salt  is  insoluble. 

Hippuric  acid  is  best  prepared  from  the  fresh  urine  of  a  horse 
or  cow.  The  urine  is  boiled  a  few  minutes  with  an  excess  of  milk 
of  lime.  The  liquid  is  filtered  while  hot,  concentrated  and  then 
cooled,  and  the  hippuric  acid  precipitated  by  the  addition  of  an 
excess  of  hydrochloric  acid.  The  crystals  are  pressed,  dissolved  in 
milk  of  lime  by  boiling,  and  treated  as  above;  the  hippuric  acid  is 
precipitated  again  from  the  concentrated  filtrate  by  hydrochloric 
acid.  The  crystals  are  purified  by  recrystallization  and  decolorized, 
when  necessary,  by  animal  charcoal. 

The  quantitative  estimation  of  hippuric  acid  in  the  urine  may 
be  performed  by  the  following  method  (Btjnge  and  Schmiede- 
BERG  ') :  The  urine  is  first  made  faintly  alkaline  with  soda,  evapo- 
rated nearly  to  dryness,  and  the  residue  thoroughly  extracted  with 
strong  alcohol.  After  the  evaporation  of  the  alcohol  dissolve  in. 
water,  acidify  with  sulphuric  acid,  and  completely  extract  by 
agitating  (at  least  five  times)  with  fresh  portions  of  acetic  ether. 
The  acetic  ether  is  then  repeatedly  washed  with  water,  which  is 
removed  by  means  of  a  separatory  funnel,  then  evaporated  at  a 
medium  temperature,  and  the  dry  residue  treated  repeatedly  with 
petroleum  ether,  which  dissolves  the  benzoic  acid,  oxyacids,  fat,  and 
phenol,  while  the  hippuric  acid  remains  undissolved.  This  residue 
is  now  dissolved  in  a  little  warm  water  and  evaporated  at  50-60°  C. 
to  crystallization.  The  crystals  are  collected  on  a  small  weighed 
filter.  The  mother-liquor  is  repeatedly  shaken  with  acetic  ether. 
This  last  is  removed  and  evaporated;  the  residue  is  added  to  the 
above  crystals  on  the  filter,  dried  and  weighed. 

Phenaceturic  Acid,  CoHmNOs  =  C6H5.CH,.CO.NH.CH2.COOH.  This  acid, 
which  is  produced  in  the  animal  body  by  a  grouping  of  the  phenylacetic  acid, 
CefJb.CHj.COOH,  formed  by  the  putrefaction  of  the  proteids  with  glycocoll,  has 
■been  ]n-epared  from  horse's  urine  by  Salkowski,*  but  it  probably  also  occurs 
in  human  urine. 

'  L.  c. 

*  Zeitschr.  f.  physiol.  Chem.,  Bd.  9.  See  also  E.  and  H.  Salkowski,  ihid., 
Bd.  7. 


ETHEREAL  SULPHURIC  ACIDS.  489 

Benzoic  Acid,  CtIIbOo  or  CeHs.COOH,  is  found  in  rabbit's  urine  and  some- 
times, tliougli  in  small  amounts,  in  dog's  urine  (Weyl and  V.  Aneep').  Ac- 
cording to  Jaaksveld  and  Stokvis^  and  to  Kronecker^  it  is  also  found  in 
human  urine  in  diseases  of  the  kidneys.  The  occurrence  of  benzoic  acid  in  the 
urine  seems  to  be  due  to  a  fermentative  decomposition  of  hippuric  acid.  Such 
a  decomposition  may  very  easily  occur  in  an  alkaline  urine  or  one  containing 
proteid  (Vax  de  Velde  and  Stokvis'').  In  certain  animals— pigs  and  dogs — 
the  kidneys,  according  to  Schmiedeberg  ^  and  Minkowski,'  contain  a  special 
enzyme,  Schmiedeberg's  histozym,  which  spliis  the  hippuric  acid  with  the 
separation  of  benzoic  acid. 

Ethereal  Sulphuric  Acids.  In  the  putrefactiou  of  proteids  in 
the  intestine,  phenol,  whose  mother-substance  is  considered  to  be 
tyrosin,  and  indol  and  skatol  are  produced.  The  two  last-named 
bodies,  after  they  have  been  oxidized  into  indoxyl  and  skatoxyl, 
pass  into  the  urine  as  ethereal  sulphuric  acids  after  uniting  with 
snli^huric  acid.  The  most  important  of  these  ethereal  acids  are 
phenol-  and  cresol-sulphnric  acid — which  were  formerly  also  called 
phenol-forming  substance — indoxyl-  and  skatoxyl-sulphurie  acid. 
To  this  group  belong  also  the  pyrocatecliin-sulplmric  acid.,  which 
only  occurs  in  very  small  anioants  in  human  urine,  and  uydro- 
chinon-sulpliuric  acid.,  which  appears  in  the  urine  after  poisoning 
with  phenol,  and  perhaps  under  physiological  conditions  other 
ethereal  acids  occur  which  have  not  been  isolated.  The  ethereal 
sulphuric  acids  of  the  urine  were  discovered  and  specially  studied 
by  Baujiaxx.'  The  quantity  of  these  acids  in  human  urine  is 
small,  while  horse's  arine  contains  larger  quantities.  According  to 
the  determinations  of  t.  d.  Velden"  *  the  quantity  of  ethereal  sul- 
phuric acid  in  human  urine  in  the  24  hours  varies  between  0.094 
and  0.6"20  grms.  The  relationship  of  the  sulphate-sulphuric  acid 
A  to  the  conjugated  sulphuric  acid  B  in  health  is  on  an  average  as 
10  :  1.  It  undergoes  such  great  variation,  as  found  by  Baumann" 
and  Herter  '  and  after  them  by  many  other  investigators,  that  it 
is  hardly  possible  to  consider  the  average  figures  as  normal.  After 
taking  phenol  and  certain  other  aromatic  substances,  as  also  with 
abundant   putrefaction  within  the   organism,  the   elimination   of 

'  Zeitschr.  f.  physiol.  Chem.,  Bd.  4. 

*  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  10. 

» lUd.,  Bd.  16. 

*Ibid.,  Bd.  17. 

'  Ibid.,  Bd.  14,  S.  379. 

«/6«Z.,  Bd.  17. 

'  Pfliiger's  Arch.,  Bdd.  12  and  13. 

8  Virchow's  Arch.,  Bd.  70. 

'  Zeitschr.  f.  physiol.  Chem.,  Bd.  1. 


490  THE   URINE. 

ethereal  sulphuric  acid  is  greatly  increased.  On  the  contrary  it  is 
diminished  when  the  putrefaction  in  the  intestine  is  reduced  or 
prevented.  For  this  reason  it  may  be  greatly  diminished  b^  carbo- 
hydrates and  one-sided  milk  diet.^  The  elimination  of  ethereal 
sulphuric  acid  has  also  been  diminished  in  certain  cases  by  certain 
therapeutic  agents  which  have  an  antiseptic  acid ;  still  the  state- 
ments are  not  unanimous.^ 

Great  weight  has  been  put  upon  the  relationship  between  the 
total  sulphuric  acid  and  the  conjugated  sulphuric  acid,  or  between 
the  conjugated  sulphuric  acid  and  the  sulphate-sulphuric  acid,  in 
the  study  of  the  intensity  of  the  putrefaction  in  the  intestine  under 
different  conditions.  Several  investigators,  F.  Mullee,"  Sal- 
KOWSKi,^  and  v.  Nooeden,^  consider  correctly  that  this  relation- 
ship is  only  of  seconda.ry  value  and  that  it  is  more  correct  to 
consider  the  absolute  value.  It  must  be  remarked  that  the  absolute 
values  for  the  conjugated  sulphuric  acid  also  undergo  great  varia- 
tion, so  that  it  is  at  present  impossible  to  give  the  upper  or  lower 
limit  for  the  normal  value. 

Phenol-  and  p-Cresol-sulphuric  Acid,  C^H^.O.SO^.OH  and 
C  H  .O.SO  .OH.  These  acids  are  found  as  alkali  salts  in  human 
urine,  in  which  also  orthocresol  has  been  detected.  The  quantity 
of  cresol-sulphuric  acid  is  considerably  greater  than  phenol-sul- 
phuric acid.  In  the  quantitative  estimation  the  phenols  set  free 
from  the  two  ethereal  acids  are  determined  together  as  tribrom- 
phenol.  The  quantity  of  phenols  which  are_  separated  from  the 
ethereal  sulphuric  acids  of  the  urine  amounts  to  17-51  milligrammes 
in  the  24  hours  (Munk  ').  The  methods  for  the  quantitative 
estimation  used  heretofore  give,  according  to  Eumpf  '  and  also 
KosSLER  and  PEi^Tiq-Y,  ^  such  inaccurate  results  that  new  determin- 
ations are  very  desirable.     After  a  vegetable  diet  the  quantity  of 

'  See  Hirscliler,  Zeitsclir.  f.  physiol.  Chem.,  Bd.  10;  Biernacki,  Deutsch. 
Arch.  f.  klin.  Med.,  Bd.  49,  Rovigbi,  Zeitsclir.  f.  physiol.  Chem.,  Bd.  16; 
Winteraitz,  ibid.,  and  Schmitz,  ibid.,  Bdd.  17  and  19. 

2  See  Baiimannand  Morax,  Zeitschr.  f.  physiol.  Chem.,  Bd.  10;  SteifE,  Zeit- 
schr.  f.  klin.  Med.,  Bd.  16;  Rovighi,  1.  c;  Stern,  Zeitschr.  f.  Hygiene,  Bd.  12; 
and  Bartoschewitsch,  Zeitschr.  f.  physiol.  Chem.,  Bd.  17. 

3  Zeitschr.  f.  klin.  Med.,  Bd.  12. 

*  Zeitschr.  f.  physiol.   Chem.,  Bd.  12. 
^  Zeitschr.  f.  klin.  Med.,  Bd.  17. 
«  Pfliiger's  Arch.,  Bd.  12. 
■"  Zeitschr.  f .  physiol.  Chem. ,  Bd.  16. 
»  Ibid.,  Bd.  17. 


PHENOL-   AND  P-CRESCL-SULPHURIC  ACID.  491 

these  ethereal-sulpliuric  acids  is  greater  than  after  a  mixed  diet. 
After  taking  carbolic  acid,  which  is  in  great  part  converted  by 
synthesis  within  the  organism  into  phenol-ethereal-sulphnric  acid, 
besides  also  pyrocatechin-  and  hydrochinon-sulphuric  acid,'  and  also 
when  the  amount  of  sulphuric  acid  is  not  sufficient  to  combine  with 
the  phenol,  forming  phenyl-glycnronic  acid,'  the  quantity  of 
phenols  and  ethereal-sulphuric  acids  in  the  urine  is  considerably 
increased  at  the  expense  of  the  sulphate-sulphuric  acid. 

An  increased  elimination  of  phenol-sulphuric  acids  occurs  in 
active  putrefaction  in  the  intestine  with  stoppage  of  the  contents  of 
the  intestine,  as  in  ileus,  diffused  peritonitis  with  atony  of  the 
intestine,  or  tuberculous  enteritis,  but  not  in  simple  obstruction. 
The  elimination  is  also  increased  by  the  absorption  of  the  products 
of  putrefaction  from  purulent  wounds  or  abscesses.  An  increased 
elimination  of  phenol  has  been  observed  in  a  few  other  cases  of 
diseased  conditions  of  the  body.^ 

The  alkali  salts  of  phenol-  and  cresol-sulphuric  acids  crystallize 
in  white  plates,  similar  to  mother-of-pearl,  which  are  rather  freely 
soluble  in  water.  They  are  soluble  in  boiling  alcohol,  but  only 
slightly  soluble  in  cold.  On  boiling  with  dilate  mineral  acids  they 
are  decomposed  into  sulphuric  acid  and  the  corresponding  phenol. 

Phenol-sulphuric  acids  have  been  synthetically  prepared  by 
Baumaxx  from  potassium  pyrosnlphate  and  phenol-  or  p-cresol- 
potassium.  For  the  method  of  their  preparation  from  nrine,  which 
is  rather  complicated,  the  reader  is  referred  to  other  text-books. 
The  quantitative  estimation  of  these  ethereal  sulphuric  acids  is  done 
by  determining  the  amount  of  phenol  which  may  be  separated  from 
the  urine  as  tribromphenol.  In  this  determination,  when  the  urine 
is  not  specially  rich  in  phenol,  about  one  fourth  of  the  total  quantity 
in  the  24  hours  is  used;  it  is  acidified  with  concentrated  hydro- 
chloric acid — 5  c.  c.  for  every  100  c.  c.  of  urine — and  distilled  until 
a  portion  of  the  distillate  does  not  give  the  slightest  reaction  for 
phenol  with  Millox's  reagent  or  with  bromine-water.  The  distil- 
late is  now  carefully  neutralized  with  soda  solution  (which  combines 
with  the  benzoic  acid,  etc.)  and  again  distilled  until  a  portion  of 
the  distillate  is  free  from  j)henol,  as  shown  by  the  above-mentioned 
reagents.  This  distillate  is  treated  with  bromine-water  until  a  per- 
manent yellow  color  is  produced,  and  then  allowed   to  stand  for 

'  See  Baumaan,  Pflliger's  Arch.,  Bdd.  12  and  13,  audBaumann  and  Preusse, 
Zeitscbr.  f.  physiol.  Chern.,  Bd.  3,  S.  156. 

'  Schmiedeberg,  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  14. 

^  See  G.  Hoppe-Seyler,  Zeitschr.  f.  physiol.  Chem. ,  Bd.  12.  This  contains 
also  all  references  to  the  literature  on  this  subject. 


492  THE    URINE. 

about  24  hours  in  the  cold;  the  crystalline  precipitate  is  then 
collected  on  a  small  weighed  filter,  washed  with  dilute  bromine- 
water,  dried  over  sulphuric  acid  without  the  use  of  a  yacuum,  and 
weighed  (100  parts  tribromphenol  correspond  to  28.4  parts  phenol). 
It  is  assumed  that  the  paracresol  is  first  converted  by  the  bromine- 
water  into  tribromcresol  bromine,  and  that  this  is  then  gradually 
changed  into  tribromphenol  with  the  discharge  of  carbon  dioxide. 
As  shown  by  Eumpf  '  this  is  not  the  case,  but  dibromcresol  is  chiefly 
formed  instead.  This  method  is  therefore  not  available  for  this  and 
other  reasons.  Among  the  other  methods  which  have  been  sug- 
gested, the  following  seems  to  be  the  most  available. 

KossLEE  and  Penny's  '  method.  This  method  is  a  modification 
of  Messinger  and  Vortmann's''' volumetric  process  for  estimat- 
ing phenols.     The  principle  of  this  process  is  as  follows:  The  liquid 

n 
containing  phenol  is  treated  with  —  caustic  soda  until  strongly 

alkaline,  warmed  on  the  water-bath  in  a  fiask  with  a  glass  stopper, 

and  then  treated  with  an  excess  of  —  iodine  solution,  the  quantity 

being  exactly  measured.  Sodium  iodide  is  first  formed  and  then 
sodium  hypoiodite,  which  latter  forms  tri-iodophenol  with  the 
phenol  according  to  the  following  equation : 

C„H,OH  +  SNalO  =  C,HJ3.0H  +  3NaOH. 

On  cooling  acidify  with  sulphuric  acid,  and  determine  by  titration 

with  —  sodium  thiosulphate  solution  the  excess  of  iodine  not  used. 

This  process  is  also  available  for  the  estimation  of  paracresol.  Each 
<3.  c.  of  the  iodine  solution  used  is  equivalent  to  1.5670  grms. 
phenol  or  1.8018  grms.  cresol.  As  the  determination  does  not  give 
any  idea  as  to  the  variable  proportions  of  the  two  phenols,  the 
quantity  of  iodine  used  must  be  calculated  as  one  or  the  other  of 
the  two  phenols.  In  regard  to  greater  details,  and  especially  to 
precaations,  we  must  refer  the  reader  to  the  original  article  of 
Kossler  and  Penny. 

The  methods  for  the  separate  determination  of  the  conjugated 
sulphuric  acid  and  the  sulphate-sulphuric  acid  will  be  spoken  of 
later  in  connection  with  the  determination  of  the  sulphuric  acid  of 
the  urine. 

Pyrocatechin-sulphuric  Acid  (and  Pyrocatechin).  This  acid  was  first  found 
in  horse's  urine  in  rather  larg^e  quantities  by  Batjmann.'*  It  occurs  in  human 
urine  only  in  the  very  smallest  quantities,  and  perhaps  not  constantly,  but  it 

1  Zeitschr.  f.  physlol.  Chem.,  Bd.  16. 

■^  Ibid.,  Bd.  17. 

^  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  22. 

''  Baumann  and  Herter,  Zeitschr.  f.  physiol.  Chem.,  Bd,  1. 


INDOXYL-SLl.PIU'RW  AVID.  493 

occurs  abundantly  in  the  urine  after  talking  phenol,  pyrocatechin,  or  proto- 
catechuic  acid. 

On  an  exclusive  meat  diet  this  acid  does  not  occur  in  the  urine,  and  it  there- 
fore originates  from  the  vegetable  food.  It  probably  originates  from  the  i)ro- 
tocatecliuic  acid,  which,  according  to  Preusse,'  passes  in  jiart  into  the  urii.e 
as  pyrocatechin-sulphuric  acid.  This  acid  may  also  ]jerliaps  depend  on  oxida- 
tion of  phenol  within  the  organism  (Baumann  and  Preusse^). 

Pyrocatechin,  or  o-Dioxybenzol,  C6H4(0H)2,  was  first  observed  in  the 
urine  ot  a  child  (Ebstein  and  J.  MlIller^).  The  reducing  body  alcapton, 
first  found  by  Bodeker  *  in  human  urine  and  which  was  ccnisidered  for  a  long 
time  as  identii'al  with  pyrocatechin,  was  probably  homugentisir  acid  or  uroleuic 
acid  (see  below). 

Pyrocatechin  crystallizes  in  prisms  which  are  soluble  in  alcohol,  ether,  and 
water.  It  melts  at  102-104°  C.  and  sublimesi  n  shining  plates.  The  watery 
solution  becomes  green,  brown,  and  ultimately  black  in  tlie  presence  of  alkali 
and  the  oxygen  of  the  air.  If  very  dilute  ferrc  chloride  is  treated  with  tartaric 
acid  and  tlien  made  alkaline  with  ammonia,  and  this  added  to  a  watery  solution 
of  pyrocatechin,  we  obtain  a  violet  or  cherry-red  liquid  which  becomes  green 
on  saturating  with  acetic  acid.  Pyrocatechin  is  precipitated  by  lead  acetate. 
It  reduces  an  ammoniacal  silver  solution  at  the  ordinary  temperature  and 
reduces  alkaline  copper-oxide  solutions  with  heat,  but  does  not  reduce  bismuth 
oxide. 

A  urine  containing  pyrocatechin,  if  exposed  to  the  air,  especially  when  alka- 
line, quickly  becomes  dark  and  reduces  alkaline  copper  solutions  when  heated. 
In  detecting  pyrocatechin  in  the  urine  it  is  concentrated  when  necessary, 
filtered,  boiled  with  the  addition  of  sulphuric  acid  to  remove  the  phenols,  and 
repeatedly  shaken  after  cooling  with  ether.  The  ether  is  distilled  from  the 
sevej-al  ethereal  extracts,  the  residue  neutralized  with  barium  carbonate  and 
shaken  again  with  ether.  The  pyrocatechin  which  reujains  after  evaporating^ 
the  ether  may  be  purified  by  reerystallization  from  benzol. 

Hydrochinon,  or  p-Dioxtbenzol,  C6H4(OH)a,  often  occurs  in  the  urine  after 
the  u.-e  of  phenol  (Baumann  and  Preusse).  The  dark  color  which  certain 
urines,  so-called  "carbolic  urines,"  take  in  the  air  is  due  to  decomposition 
products.  Hydrochinon  does  not  occur  as  a  normal  constituent  of  urine,  but 
after  the  administration  of  hydrochinon;  according  to  Lewin^  it  passes  into 
the  urine  of  rabbits  as  ethereal-sulphuric  acid,  as  a  decomposition  product  of 
arbutin. 

Hydrochinon  forms  rhombical  crystals  which  are  readily  soluble  in  water, 
alcohol,  and  ether.  It  melts  at  169°  C.  Like  pyrocatechin,  it  easily  reduces 
metallic  oxides.  It  acts  like  pyrocatechin  with  alkalies,  but  is  not  precipitated 
with  lead  acetate.  It  is  oxidized  into  chinon  by  ferric  chloride  and  other  oxidiz- 
ing agents,  and  chinon  is  detected  by  its  peculiar  odor.  Hydrochinon-sul- 
phuric  acid  is  detected  in  the  urine  by  the  same  methods  as  pyrocatechin-sul- 
phuric acid. 

Indoxyl-sulphuric  acid,  C^n,NSO,  or  C,H,N.O.SO,.OH,  also 
called  URINE  indicax,  formerly  called  uroxanthin  (Heller), 
occurs  as  alkali-salt  in  the  urine.  This  acid  is  the  mother-substance 
of  a  great  part  of  the  indigo  of  the  urine.  The  quantity  of  indigo 
which  can  be  separated  from  the  urine  is  considered  as  a  measure 
of  the  quantity  of  indoxyl-sulphuric  acid  (and  indoxyl-glycuronic 

'  Zeitschr.  f.  physiol.  Chem.,  Bd.  2. 

'  Ibid. ,  Bd.  3. 

»  Virchow's  Arch.,  Bd.  62. 

*  Zeitschr.  f.  rat.  Med.  (3),  Bd.  7. 

»  Virchow's  Arch.,  Bd.  92. 


494  THE    URINE. 

acid)  contained  in  the  urine.  This  amount,  according  to  Jaffe,' 
for  man  is  5-20  milligrammes  per  24  hours.  Horse's  urine  contains 
about  25  times  as  much  indigo-forming  substance  as  human  urine. 

Indoxyl-snlphuric  acid  is  derived,  as  above  mentioned  (page 
489),  from  indol,  which  is  first  oxidized  in  the  body  into  indoxyl 
and  then  is  coupled  with  sulphuric  acid.  After  subcutaneous 
injection  of  indol  the  elimination  of  indican  is  considerably 
increased  (Jaffe,^  Baumais'N'  and  Brieger^).  It  is  also  increased 
by  the  introduction  of  orthonitropbenylpropiolic  acid  in  the  organ- 
ism of  animals  (G.  Hoppe-Setler^).  Indol  is  formed  by  the 
putrefaction  of  proteids,  and  it  is  therefore  easy  to  understand  why 
the  quantity  of  indoxyl-sulphuric  acid  is  greater  with  a  meat  than 
with  a  vegetable  diet.  The  putrefaction  of  secretions  rich  in  proteid 
in  the  intestine  explains  also  the  occurrence  of  indican  in  the  urine 
during  starvation.  Gelatine,  on  the  contrary,  does  not  increase  the 
elimination  of  indican.  An  abnormally  increased  elimination  of 
indican  occurs  in  such  diseases  as  obstruct  the  small  intestine, 
causing  an  increased  putrefaction,  thus  producing  an  abundant 
formation  of  indol.  Such  an  increased  elimination  of  indican 
occurs  on  tying  the  small  intestine  of  a  dog,  but  not  the  large 
intestine  (Jaffe*). 

The  elimination  of  indican  may  also  be  caused  by  the  putrefac- 
tion of  proteids  in  other  organs  and  tissues  of  the  body  besides  the 
intestine.  An  increased  elimination  of  indican  has  been  observed 
in  many  diseases",  and  in  these  cases  the  quantity  of  phenol  elimi- 
nated is  generally  increased.  A  urine  rich  in  phenol  is  not  always 
rich  in  indican. 

The  potassium- salt  of  indoxyl-sulphuric  acid,  which  was  prepared 
by  Baumann  and  Brieger'  from  the  urine  of  a  dog  fed  on  indol, 
crystallizes  in  colorless,  shining  plates  or  leases  which  are  easily 
soluble  in  water  but  less  readily  in  alcohol.  It  is  split  by  mineral 
acids  into  sulphuric  acid  and  indoxyl.     The  latter  without  access 

1  Pfliiger's  Arch.,  Bd.  3. 

*  Centralbl.  f.  d   med.  Wissenscli.,  1872. 

*  Zeitsc  ir.  f.  physiol.  Cuem.,  Bd.  3. 
^Ibid.,  Bdd.  7  and  8. 

*  Vircliow's  Arcb.,  Bd.  70. 

*  See  Jaffe,  Pfliiger's  Arcli.,  Bd.  3;  Senator,  Centralbl.  f.  d.  med.  Wissenscli., 
1877;  G.  Hoppe-Seyler,  Zeitscb-.  f.  physi  .1.  Ciiem.,  Bd.  12  (coniains  older  liter- 
ature); also  Berl.   klin.  Wochenscbr.,  1892. 

1  Zeitscbr.  f.  physiol.  Chem.,  Bd.  3,  S.  254. 


TESTS  FOE  INDICAN.  495 

of  air  passes  into  a  red  compound,  indoxyl-red,  but  in  the  presence 
of  oxidizing  reagents  is  converted  into  indigo-blue:  2CgH,N0  + 
20  =  C,,H,„N,0,  +  3H,0.  The  detection  of  indican  is  based  on 
this  last  fact. 

For  the  rather  complicated  preparation  of  indoxyl-snlphnric  acid 
as  potassium-salt  from  uriue  the  reader  is  referred  to  other  text- 
books. For  the  detection  of  indican  in  urine  in  ordinary  cases  the 
following  method  of  Jaffe/  which  also  serves  as  an  approximate 
test  for  the  quantity  of  indican,  is  sufficient. 

Jaffe's  Indican  Test.  20  c.  c.  of  urine  are  treated  in  a  test- 
tube  with  2-3  c.  c.  chloroform  and  mixed  with  an  equal  volume  of 
concentrated  hydrochloric  acid.  Immediately  after  a  concentrated 
chloride-of-lime  solution  or  a  ^fo  potassium  permanganate  solution 
is  added  drop  by  drop,  and  after  each  drop  the  mixture  is 
thoroughly  shaken.  The  chloroform  is  gradually  colored  faintly  or 
strongly  blue.  An  excess  of  oxidizing  reagent,  especially  chloride 
of  lime,  interferes  with  the  reaction  and  must  therefore  be  avoided. 
The  test  is  repeated  with  somewhat  varying  amounts  of  oxidizing 
material  until  a  point  is  found  at  which  the  maximum  coloration  of 
the  chloroform  takes  place.  From  the  intensity  of  the  color  the 
quantity  of  indigo  is  determined. 

Obermayer^  uses  fuming  hydrochloric  acid  containing  2-4 
parts  ferric  chloride  per  litre  to  decompose  the  indican  and  to 
oxidize  the  indoxyl.  The  urine  is  first  precipitated  with  not  too 
much  lead  acetate  and  the  filtrate  shaken  for  1-2  minutes  with  an 
equal  volume  of  the  above  hydrochloric  acid.  The  indigo  blue  is 
taken  up  by  chloroform  in  this  case  also. 

According  to  Rosi:n"'  some  indigo-red  is  always  formed  besides 
the  indigo-blue  in  Jaffe's  indican  test.  Greater  quantities  of 
indigo-red  are  formed  when  the  decomposition  of  the  indican  takes 
place  in  the  warmth  (see  Kosenbach's  urine  test). 

An  exact  determination  of  the  amount  of  indigo  in  urine  is  very 
rarely  made.  The  methods  suggested  for  this  purpose  are  very 
complicated,  and  even  then  they  are  not  quite  accurate;  therefore 
the  reader  is  referred  to  other  text-books  for  their  description. 

Indol  seems  also  to  pass  into  the  urine  as  a  glycuronic  acid, 
indoxyl-glycuronic  acid  (Schmiedbberg  *).  Such  an  acid  has  been 
found  in  the  urine  of  animals  after  the  administration  of  the 
sodium-salt  of  o-nitrophenylpropiolic  acid  (G.  Hoppe-Setler^). 

Skatoxyl-sulphuric   Acid,    C.H.NSO,    or    C,H,.N.O.SO,.OH. 

'  Pflliger's  Arch.,  Bd.  3. 

*  Wien.  klin.  Wochenscbr.,  1890. 
'Vircbow's  Arch.,  Bd.  123. 

*  Arch.  f.  exp.  Path.  u.  Pharm. ,  Bd.  14. 

*  Zeitschr.  f.  pLysiol.  Chem.,  Bdd.  7  and  8. 


496  THE    URINE. 

The  potassium-salt  of  this  acid  seems  to  occur  generally  in  human 
urine  as  a  chromogen,  which  yields  a  red  or  violet  coloring  matter 
on  decomposing  with  strong  acids,  and  an  oxidizing  reagent.  This 
salt  has  been  prepared  by  Otto  '  from  diabetic  human  urine.  Little 
is  known  of  the  quantity  of  this  skatol-chromogen,  to  which  prob- 
ably also  the  skatoxyl-glycuronic  acid  must  be  counted,  under 
physiological  and  pathological  conditions. 

Skatoxyl-sulphuric  acid  originates  from  skatol  formed  by  putre- 
faction in  the  intestine,  which  is  coupled  with  sulphuric  acid  after 
oxidation  into  skatoxyl.  That  skatol  introduced  into  the  body 
passes  partly  as  an  ethereal-sulphuric  acid  into  the  urine  has  been 
shown  by  Briegee,.*  Indol  and  skatol  act  diiferently,  at  least  in 
dogs;  indol  producing  a  considerable  amount  of  ethereal-sulphuric 
acid,  while  skatol  only  gives  a  small  quantity  (Mester  ^).  Skatol 
seems  partly  to  pass  into  the  urine  as  a  shatoxyl-glycuronic  acid. 

The  potassium-salt  of  skatoxyl-sulphuric  acid  is  crystalline;  it 
dissolves  in  water,  but  with  difficulty  in  alcohol.  A  watery  solution 
becomes  deep  violet  with  ferric  chloride,  and  red  with  concentrated 
nitric  acid.  The  salt  is  decomposed  by  concentrated  hydrochloric 
acid  with  the  separation  of  a  red  precipitate.  The  nature  of  this 
red  coloring  matter  produced  by  the  decomposition  of  skatoxyl- 
sulphuric  acid  is  not  well  known;  neither  is  the  relationship  existing 
between  this  and  other  red  coloring  matters  in  the  urine  known. 
On  distillation  with  zinc-dust  the  skatol  chromogen  yields  skatol. 

Urines  containing  skatoxyl  are  colored  dark  red  to  violet  by 
Jaefe's  indican  test  even  on  the  addition  of  hydrochloric  acid; 
with  nitric  acid  they  are  colored  cherry-red,  and  red  on  warming 
with  ferric  chloride  and  hydrochloric  acid.  The  coloring  matter 
which  yields  skatol  with  zinc-dust  may  be  removed  from  the  urine 
by  ether.  Urines  rich  in  skatoxyl  darken  when  allowed  to  stand  in 
the  air  from  the  surface  downward,  and  may  become  reddish,  violet, 
or  nearly  black.  Rosiisr '  is  of  the  opinion  that  no  skatol-chromogen 
exists  in  human  urine,  and  that  the  observations  made  heretofore 
were  due  to  a  confusion  with  indigo-red  or  urorosein. 

Salkowski^  lias  sliown  that  the  occurrence   oi  skatol-earbo7iie  acid,C^^t. 
N.COOH,  in   normal  urine  is  probable.     This  is  also  a  putrefaction  product. 

»  Pfluger's  Arch.,  Bd.  33. 

"^  Ber.  d.  deutsch.  chem.  Qeseilsch.,  Bd.  12,  and  Zeitschr.  f.  physiol.  Chem., 
Bd.  4,  S.  414. 

'Zeitschr.  f.  physiol.  Chem.,  Bd.  12. 

*L.  c. 

'  Zeitschr.  f.  physiol.  Chem.,  Bd.  9. 


AROMATIC  OXTACIDS.  497 

Aromatic  Oxyacids.  In  the  pntrefaction  of  profceids  in  the 
intestine,  paraoxyphenyl-acetic  acii/,  C5H^(0H).CH,C00H,  and 
paraoxi/phenyl-projnonic  acid,  0^11^(011). C,H^.COOH,  are  formed 
from  ty rosin  as  intermediate  steps,  and  these  in  great  part  pass 
unchanged  into  the  urine.  They  were  first  detected  by  Baumann".' 
The  quantity  of  these  acids  is  usually  very  small.  They  are 
increased  by  the  same  circumstances  as  phenol,  especially  in  acute 
phosphorus-poisoning,  in  which  the  increase  is  considerable.  A 
small  portion  of  these  oxyacids  is  combined  with  sulphuric  acid. 

Besides  these  two  oxyacids  which  regularly  occur  in  human 
urine  we  sometimes  have  other  oxyacids  in  urines.  To  these  belong 
homogentisic  acid  and  uroleucicacid,  which  form  the  specific  constit- 
uents of  the  urine  in  most  cases  of  alcaptonuria,  oxymandelic  acid, 
found  by  Schultzex  and  Riess"  in  urine  in  acute  atrophy  of  the 
liver,  oxyliydroparacumaric  acid,  found  by  Blendeemann  '  in  the 
urine  on  feeding  rabbits  with  tyrosin,  gallic  acid,  which,  according 
to  Baumaxx,*  sometimes  appears  in  horse's  urine,  and  kynurenic 
acid  (oxychinolincarbonic  acid),  which  has  only  been  found  up  to 
the  present  time  in  dog's  urine.  The  first  two  above-mentioned 
oxyacids,  and  also  homogentisic  and  uroleucic  acids,  will  be  treated 
of  here. 

Paraoxyphenylacetic  acid  and   p-oxyphenylpropionic  acid  are 

crystalline  and  are  both  soluble  in  water  and  in  ether.     The  first 

melts  at  148°  C.  and  the  other  at  125°  C.     Both  give  a  beautiful 

red  coloration  on  being  warmed  with  Millox's  reagent. 

To  detect  the  presence  of  these  oxyacids  proceed  in  the  following  way 
(Baumaj^x)  :  Warm  the  urine  for  a  while  on  the  water-bath  witli  hydrochloric 
acid,  in  order  to  drive  off  the  volatile  phenols.  After  cooling-  shake  three  times 
with  ether,  and  then  shake  the  ethereal  extracts  with  dilute  soda  solution, 
which  dissolves  the  oxyacids,  while  the  residue  of  the  phenols  soluble  in  ether 
remains.  The  ahxaline  solution  of  the  oxyacids  is  now  faintly  acidifi -d  with 
sulphuric  acid,  shaken  again  with  ether,  the  ether  removed  and  allowe  ;  to  evap- 
orate, the  residue  dissolved  in  a  little  water,  and  the  solution  tested  with 
MiLLONS  reagent.  The  two  oxyacids  are  best  differentiated  by  their  different 
melting-points.  The  reader  is  referred  to  other  works  for  the  method  of 
isolating  and  separating  these  two  oxyacids. 

Homogentisic  acid,  C,H,0,  or  C,H,(OH),.CH,.COOH.  This 
acid  was  detected  by  Wolkow  and  Baumann.^     They  isolated  it 

'  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bdd.  12  and  13,  and  Zeitschr.  f. 
physiol.  Chem.,  Bd.  4. 

»  Chem.  Centralbl.,  1869. 

»  Zeitschr.  f.  Physiol.  Chem.,  Bd.  6,  S.  257. 

*  lUd..  Bd.  6,  S.  193. 

^  Ibid.,  Bd.  15. 


498  THE   URINE. 

from  the  urine  iu  a  case  of  alcaptonuria  (see  below)  and  showed  that 
the  characteristics  of  so-called  alcaptonuric  urine  in  this  case  were 
due  to  this  acid.  This  acid  has  later  been  found  in  other  cases  of 
alcaptonuria  by  Embden"/  Garniee  and  Voiein/  and  Ogdek.' 
Glycosuric  acid,  isolated  from  alcaptonuric  urine  by  Maeshall  *  and 
recently  by  G-eygee/  seems  to  be  identical  with  homogentisic  acid. 
Tyrosin  is  considered  as  the  mother-substance  of  this  acid.  On  the 
introduction  of  tyrosin  in  persons  with  alcaptonuria,  "Wolkow  and 
BAUMANisr  and  Embden  observed  a  greater  or  less  increase  in  the 
quantity  of  homogentisic  acid  in  the  urine.  According  to  Wolkow 
and  Baumann  this  acid  is  formed  from  the  tyrosin  by  abnormal 
putrefactive  processes  in  the  upper  part  of  the  intestine. 

Homogentisic  acid  is  that  dioxyphenyl-acetic  acid  derived  from 
hydrochinon.  On  fusion  with  potash  it  yields  gentisic  acid  (hydro- 
chinon-carbonic  acid)  and  hydrochinon.  When  introduced  into  the 
intestinal  tract  of  dogs  it  is  in  part  converted  into  tolu-hydrochinon, 
which  is  eliminated  in  the  form  of  ethereal-sulphuric  acid.  Homo- 
gentisic acid  has  recently  been  prepared  synthetically  by  Batjman"1S" 
and  Feankel/  starting  with  gentisic  aldehyde. 

Homogentisic  acid  crystallizes  with  1  mol.  water  in  large,  trans- 
parent prismatic  crystals,  which  become  non-transparent  at  the 
temperature  of  the  room  with  the  loss  of  water  of  crystallization. 
They  melt  at  146.5-147°  C.  They  are  soluble  in  water,  alcohol, 
and  ether,  but  nearly  insoluble  in  chloroform  and  benzol.  Homo- 
gentisic acid  is  optically  inactive  and  non-fermentable.  Its  watery 
solution  has  the  properties  of  so-called  alcaptonuric  urine.  It 
becomes  greenish  brown  from  the  surface  downward  on  the  addition 
of  very  little  caustic  soda  or  ammonia  with  excess  of  oxygen,  and  on 
stirring  it  becomes  quickly  dark  brown  or  black.  It  reduces  alka- 
line copper  solutions  with  even  slight  heat,  and  ammoniacal  silver 
solutions  immediately  in  the  cold.  It  does  not  reduce  alkaline 
bismuth  solutions.  Among  the  salts  of  this  acid  we  must  mention 
the  lead  salt  containing  water  of  crystallization  and  34.79^  Pb. 
This  salt  melts  at  214-215°  C. 

'  Zeitsclir.  f.  pliysiol.  Chem.,  Bdd.  17  and  18. 

2  Arch   de  Physiol.,  (5)  Tome  4. 

3  Z^'itsclir.  f.  physiol.  Cliem.,  Bd.  20. 

4  See  Malv's  Jaliresber.,  Bd.  17 

5  Pbiinu.  Ztg.,  6  Aug.  1893,  S.  488.     Cited  from  Embden,  Zeitschr.  f.  phys- 
iol. Chem.,  Bd.  18. 

6  Zeitschr.  f.  Physiol.  Chem.,  Bd.  20. 


URINARY  PIGMENTS.  499 

In  preparing  this  acid  the  strongly  acidified  nrine  is  shaken 
■with  ether.  The  residue  obtained  on  the  distillation  of  the  etlier 
is  dissolved  in  water,  the  solution  heated  to  boiling  and  treated  with 
a  lead  acetate  solution  (1  :  5),  and  the  brown  resinous  precipitate 
quickly  separated  by  filtration.  The  lead  salt  gradually  crystallizes 
from  the  filtrate.  This  is  decomposed  by  sulphuretted  hydrogen 
and  the  acid  obtained  as  crystals  from  the  filtrate  after  carefully 
concentrating  the  filtrate  finally  in  vacuo. 

In  regard  to  the  quantitative  estimation  we  proceed  according 

to  the  suggestion  of  Baumanx  by  titrating  the  acid  with  a  —  silver 

•solution.       As  regards  details  of  this  method  we  must   refer  the 
reader  to  the  original  publication.' 

Tlroleucic  acid,  C9H10O5,  is,  according  to  Huppert,'  probably  at  rioxypbenol- 
propionic  acid,  (HO^a.CsHaCHo.CH.j.C'OOH.  Tbis  acid  was  first  prepared  by 
Kirk'  from  tbe  urine  of  children  with  alcaptonuria.  According  to  WoLKOW 
and  Bacmann  it  is  not  id  ntical  with  liomogentisic  acid,  and  bas  a  melting- 
point  of  133°  C.  Otberwise,  in  regard  to  its  behavior  with  alkalies,  with  ac- 
cess of  air,  and  also  with  alkaline  copper  solutions  and  ainiiioniacal  silver  solu- 
tions, it  is  similar  to  homogeutisic  acid.  In  chemical  properties  it  is  very  sim- 
ilar to  gallic  acid. 

Urinary  Pigments  and  Chromogens.  The  yellow  color  of 
normal  urine  depends  apparently  upon  several  coloring  matters 
which  have  not  been  isolated  and  studied.  Besides  these  bodies, 
UROBILIN  sometimes  occurs  in  fresh  normal  nrine,  but  by  no  means 
always.  Instead  of  urobilin,  normal  urine  often  contains  a  mother- 
substance  of  the  same,  a  chromogen  or  urobilinogen^,  from  which 
the  urobilin  is  gradually  formed  by  oxidation  on  allowing  the  urine 
to  stand  exposed  to  the  air  (Jaffe,*  Disque,'  and  others).  Besides 
this  chromogen,  urine  contains  various  other  bodies  from  which 
coloring  matters  may  be  produced  by  the  action  of  chemical  agents. 
Humin  substances  (perhaps  in  part  from  the  carbohydrates  of  the 
nrine)  may  be  formed  by  the  action  of  acids  (v.  Udranszky  ') 
without  regard  to  the  fact  that  such  substances  may  sometimes 
originate  from  the  reagents  used,  as  from  impure  amyl-ahsohol 
(v.  Udranszkt  and  Hoppe-Seyler').      To  these  humin  bodies 

■  Zeitschr.  f.  pbysiol.  Chem.,  Bd.  16. 

*  Hiippert-Neubauer,  Analyse  des  Harns,  10.  Aufl.,   S.  246. 

'  Brit.  Med.  Journal.  18S6  and  1888;  Journal  of  Anat.  and  Physiol.,  Vol.  23. 

*  Centralbl.  f.  d.  med.  Wisst-nsch  ,  1868  and  1869;  Virchow's  Arch.,  Bd.  47. 

*  Zeitschr.  f.  pbysiol.  Chem.,  Bd.  2. 

*  Ii;i.,  Bdd.  11  and  12. 

^  Hoppe-Seyler,  Ber.  d.  deutscb.  Chem.  Gellscb.,  Bd.  18,  and  v.  Udranszky, 
Zeitschr.  f.  pbysiol  Chem.,  Bd.  13. 


600  THE   URINE. 

developed  by  the  action  of  acid  in  normal  urine  when  exposed  to 
the  air  must  be  added  the  urophaik  of  Heller,'  the  various 
TJROiiELAisriisrs,  and  other  bodies  described  by  different  investigators 
(Plos'z,^  Thudichum/  SchujS'ck'),  Indigo-blue  (uroglaucik 
of  Heller,  UROCTA:Nri]sr,  CTAisruRiisr,  and  other  coloring  matters  of 
older  investigators  ^)  is  split  oif  from  the  indoxyl-sulphuric  acid  or 
indoxyl-glycnronic  acid.  Red  coloring  matters  may  be  formed  from 
the  conjugated  indoxyl  and  skatoxyl  acids,  and  urohodijST 
(Heller),  urorubin"  (Plos'z),  uroh^matik  (Harley'),  and 
perhaps  also  UROROSEiisr  (Neistcki  and  Sieber')  probably  have, 
such  an  origin. 

We  cannot  enter  into  too  many  details  of  the  different  coloring 
matters  obtained  as  decomposition  products  from  normal  urine; 
and  as  the  preformed  physiological  coloring  matters  of  urine  have 
not  been  closely  studied,  we  can  only  discuss  the  most  carefully 
investigated  urinary  pigment,  urobilin. 

Urobilin  was  first  prepared  from  urine  by  Jaffe.'  This  color- 
ing matter  occurs  in  urine  especially  in  fevers,  and  it  is  therefore 
designated  febrile  urobilust  by  MacMukn."  The  urobilin 
occurring  in  normal  urine  is  somewhat  different  from  an  optical 
standpoint  from  the  above,  and  is  called  normal  urobilin  by 
MacMunn.  As  above  stated,  a  mother-substance  of  urobilin,  a 
UROBILINOGEN,  occurs  in  the  urine,  from  which  urobilin  is  pro- 
duced by  the  action  of  the  air. 

Many  investigators  claim  that  urobilin  is  identical  with  hydro- 
bilirnbin  (Maly)  and  corresponds  to  the  composition  Cj^H^^^N^O,. 
Also,  that  urobilin  is  formed  by  a  redaction  of  bilirubin  in  the 
intestine.  The  correctness  of  this  view  is  disputed  by  others 
(MacMunn,  Le  Nobel").     According  to  MacMunn,  hydrobili- 

'  Heller's  Arcli.  (3),  Bd.  1.     Cited  from  Huppert-Neubauer,  S.  326. 
'  Zeitsclir.  f.  physiol.  Chem.,  Bd.  8. 

*  Brit.  Med.  Journal,  Vol.  201  (1864),  and  Journ.  f.  prakt.  Chem.,  Bd.  104. 

*  Cited  from  Huppert-Neubauer,  S.  509. 
'  Ibid.,  S.  161. 

'  In  regard  to  this  and  other  red  pigments  see  Huppert-Neubauer,  S.  557- 
598. 

•>  Journ.  f.  prakt.  Chem.  (2),  Bd.  26. 

*  L.  c. 

^  Proc.  Roy.  Soc,  Vols.  31  and  35;  Bar.  d.  deutsch.  chem.  Gesellsch.,  Bd. 
14;  Journal  of  Physiol.,  Vols.  6  and  10.  In  regard  to  different  urobilins,  see 
Bogoraoloff,  Maly's  Jahresber. ,  Bd.  22,  and  Eichholz,  Journal  of  Physiol., 
Vol.  14. 

'"  See  Chapter  VIII,  on  Bile-pigments. 


UROBILIN.  501 

rnbin  and  urinary  urobilin  are  not  identical  bodies,  because  he 
obtained  normal  urobilin  by  the  action  of  peroxide  of  hydrogen 
upon  a  solution  of  ha3matin  in  alcohol  containing  sulphuric  acid. 

Pigments  similar  to  urobilin,  though  not  identical,  have  been 
obtained  from  the  biliary  and  blood  coloring  matters.  Besides 
hydrobilirubin,  prepared  by  Maly  from  bilirubin,  Stokvis  ' 
obtained  a  choletelin  from  a  biliary  pigment,  cholecyanin,  by  the 
action  of  zinc  chloride  and  tincture  of  iodine,  or  by  boiling  with  a 
little  lead  peroxide.  This  choletelin  acts  like  urobilin,  but  that 
obtained  from  bilirubin  by  the  action  of  nitric  acid  does  not. 
Bodies  similar  to  urobilin  have  also  been  obtained  by  IIoppe- 
Setlee  "  by  the  reduction  of  hsematiu  and  haemoglobin  with  zinc 
and  hydrochloric  acid;  by  Le  Nobel  ^  by  treating  an  acid-alcoholic 
or  alkaline  solution  of  h^matoporphyrin  with  tin  or  zinc;  and  lastly 
by  Nencki  and  Sieber  ^  by  treating  hgematoporphyrin  with  zinc 
and  hydrochloric  acid.  From  the  observations  of  Le  Nobel  and 
Nencki  and  Sieber  it  follows  that  these  pigments  artificially  jore- 
pared  from  the  blood-coloring  matters  are  not  identical  with  urinary 
urobilin,  even  though  they  are  closely  related  from  an  optical  stand- 
point. It  must  be  left  undecided  whether  these  bodies  are  identical 
with  each  other  or  with  the  urinary  urobilin,  or  if  the  observed 
difference  is  only  due  to  a  contamination  with  other  bodies. 

We  have  numerous  observations  on  the  elimination  of  urobilin 
in  disease,  especially  by  Jaffe,  Disque,  Dreyfuss-Brissac, 
Gerhardt,  G.  Hoppe-Seyler,^  and  others.  Because  of  our  im- 
perfect knowledge  of  the  urobilin  of  the  urine  and  the  urobilin"- 
oiDiN"  (this  name  has  been  given  by  Le  Nobel  to  the  substance 
similar  to  urobilin  artificially  prepared  by  him)  it  is  difficult  to  say 
anything  positive  in  regard  to  the  occurrence  of  urobilin  in  the 
urine  in  disease.  During  the  absorption  of  large  blood  extrava- 
sations, as  also  in  diseases  connected  with  destruction  of  the  blood- 
corpuscles  or  of  the  appearance  of  methaemoglobin  in  the  blood- 
plasma,  the  urine  becomes  dark  in  color,  which  generally  depends 
upon  an  increased  elimination  of  urobilin.     The  question  whether 

'  See  Chapter  VIII. 

■^  Ber.  d.  deutscli.  cbem.  Qesellscb.,  Bd.  7. 

3  Pfliiger's  Arch.,  Bd.  40. 

*  Moiiatshefte  f.  Chem.,  Bd.  9,  and  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  24. 

'  In  regard  to  the  literature  on  this  subject  we  refer  the  reader  to  D.  Ger- 
hardt, "  Ueber  Hydrobilirubin  und  seine  Beziehungeu  zumlkterus"  (Berlin 
1889),  and  also  G.  Hoppe-Seyler,  Virchow's  Arch.,  Bd.  124. 


502  THE   URINE. 

it  depends  on  an  increased  elimination  of  nrinary  urobilin  or,  as 
is  more  probable,  upon  the  urobiliuoidin  produced  from  the 
blood-coloring  matters  is  still  doubtful.  In  icterus  the  elimination 
of  urobilin  is  often  increased,  and  indeed  cases  occur  in  which 
urobilin  is  almost  the  only  coloring  matter  which  can  be  detected 
in  the  urine  (urobiliin'icterus).  In  these  cases  we  are  probably 
dealing  with  a  urobilinoid  substance  produced  from  bilirubin  in  the 
intestinal  tract  by  reduction. 

The  urobilin  obtained  from  fever  urine  is,  according  to  Jaefe, 
amorphous,  red,  dingy  red,  or  reddish  yellow,  according  to  the 
method  of  preparation.  It  dissolves  easily  in  alcohol,  amyl-alcohol, 
and  chloroform,  but  less  readily  in  ether.  It  is  less  soluble  in, 
water,  but  the  solubility  is  augmented  in  the  presence  of  a  neutral 
salt.  It  may  be  precipitated  from  a  solution  saturated  with 
ammonium  sulphate  by  the  addition  of  sulphuric  acid  (Mehy'). 
It  is  soluble  in  alkalies,  and  is  incompletely  precipitated  from  the 
alkaline  solution  by  the  addition  of  acid.  It  is  partly  dissolved  by 
chloroform  from  an  acid  (watery-alcoholic)  solution;  alkali  solutions 
remove  the  urobilin  from  the  chloroform.  Alkaline  solutions  of 
urobilin  give  insoluble  combinations  with  salts  of  the  heavy  metals, 
such  as  zinc  and  lead.  Urobilin  does  not  give  Gmelin's  test  for 
bile-pigments. 

Neutral  alcoholic  urobilin  solutions  are  in  strong  concentration 
brownish  yellow,  in  great  dilation  yellow  or  rose-colored.  They 
have  a  strong  green  fluorescence.  The  acid-alcoholic  solutions  are 
brown,  reddish  yellow,  or  rose-red,  according  to  concentration. 
They  are  not  fluorescent,  but  show  a  faint  absorption-band,  j/, 
between  h  and  F,  which  borders  on  i^,  or  in  greater  concentration 
extends  over  F.  The  alkaline  solutions  are  brownish  yellow,  yellow, 
or  (the  ammoniacal)  yellowish  green,  according  to  concentration. 
If  some  zinc-chloride  solution  is  added  to  an  ammoniacal  solu- 
tion, it  becomes  red  and  shows  a  beautiful  green  fluorescence. 
This  solution,  as  also  that  made  alkaline  with  fixed  alkalies,  shows 
a  darker  and  more  sharply  defined  band,  d,  almost  midway  between 
h  and  F. 

The  urobilins  obtained  from  the  urine  by  MacMunn  by  another 
method,  and  that  obtained  by  Jaffe,  differ  from  each  other  mainly 
in  the  following:  A  solution  of  normal  urobilin  becomes  deeper  red 

*  Journal  de  pLarm.  et  de  chim.,  1878.  Cited  from  Maly's  Jaliresber.,  Bd.. 
8,  S.  369. 


PREPARATION  AND  ESTIMATION  OF   UROBILIN.         .A>3 

with  soda,  while  febrile  urobilin  becomes  yellow.  The  band  y  of 
normal  urobilin  disappears  on  the  addition  of  alkali,  while  the 
corresponding  band  of  febrile  urobilin  moves  towards  the  left.  The 
ethereal  solution  of  febrile  urobilin  shows  two  faint  absorption-bands 
on  each  side  of  D  which  are  not  to  be  seen  in  the  water}'  solution 
nor  in  the  urine.  Febrile  urobilin  is  a  brownish-red  and  the  normal 
a  yellowish-brown  powder.  Febrile  urobilin  is,  according  to 
MacMuxx,  converted  into  normal  urobilin  by  potassium  perman- 
ganate. 

In  preparing  urobilin  from  normal  urine,  precipitate  the  urine 
with  basic  lead  acetate  (Jaffe),  wash  the  precipitate  with  water, 
dry  at  the  ordinary  temperature,  then  boil  it  with  alcohol,  and 
decompose  it  when  cold  with  alcohol  containing  sulphuric  acid. 
The  filtered  alcoholic  solution  is  diluted  with  water,  saturated  with 
ammonia,  and  then  treated  with  zinc-chloride  solution.  This  new 
precipitate  is  washed  free  from  chlorine  with  water,  boiled  with 
alcohol,  dried,  dissolved  in  ammonia,  and  this  solution  precipitated 
with  sugar  of  lead.  This  precipitate,  which  is  washed  with  water 
and  boiled  with  alcohol,  is  decomposed  by  alcohol  containing  sul- 
phuric acid,  the  filtered  alcoholic  solution  is  mixed  with  h  vol. 
chloroform,  diluted  with  water,  and  shaken  repeatedly,  but  not  too 
energetically.  The  urobilin  is  taken  up  by  the  chloroform.  This 
last  is  washed  once  or  twice  with  a  little  water  and  then  distilled, 
leaving  the  urobilin,  which  is  purified  from  a  contaminating  red 
coloring  matter  by  means  of  ether. 

According  to  Jaffe,  tlie  coloring  matter  can  be  directly  precipitated  from 
a  fever  mine  rich  in  unibilin  by  ammonia  and  zinc  chloride,  and  this  precipi- 
tate treated  as  above.  Mehy  faiu'ly  acidifies  tbe  urine  with  sulphuric  acid 
(1-2  grms.  per  litre),  then  saturates  with  ammonium  sulphate,  washes  tbe  pre- 
cipitate on  a  filter  with  an  acidified  ammonium-sulphate  solutiun,  presses  the 
filter,  and  extracts  the  coloring  matter  with  absolute  alcohol  at  a  gentle  heat 
after  the  addition  of  a  few  drops  of  ammonia.  MacMunx  precipitates  the 
urine  with  sugar  of  lead  and  basic  lead  acetate,  decomposes  the  precipitate 
with  acidified  alcohol,  dilutes  the  solution  with  water,  shakes  with  chloroform, 
evaporates  this  last,  and  dissolves  the  residue  repeatedly  with  chloroform. 
The  method  of  preparation,  according  to  MacMunx,  is  the  same  for  both, 
urobilins,  the  normal  and  the  febrile. 

The  color  of  the  acid  or  alkaline  solution,  the  beautiful  fluores- 
cence of  the  ammoniacal  solution  treated  with  zinc  chloride,  and 
the  absorption-bands  of  the  spectrum,  all  serve  as  means  of  detect- 
ing urobilin.  In  fever  urines  the  urobilin  may  be  detected  directly 
or  after  the  addition  of  ammonia  and  zinc  chloride  by  its  spectrum. 
It  may  rlso  be  detected  sometimes  in  normal  urine  directly  or  after 
the  urine  has  stood  exposed  to  the  air  until  the  chromo.2:en  has  been 
converted  into  urobilin.  If  it  cannot  be  detected  bv  means  of  the 
spectroscope,  then  the  urine  may  be  treated  vith  a  mineral  acid 
and  shaken  with  ether.     The  ethereal  solution,   directly  or  after 


504  THE    URINE. 

coucentration,  may  be  tested  with  the  spectroscope.  It  is  often  better 
to  dissolve  the  residue,  after  the  evaporation  of  the  ether,  in  abso- 
lute alcohol,  and  use  this  for  the  spectroscopic  investigation. 
According  to  Salkowski,  the  urobilin  may  be  directly  extracted 
by  gently  shaking  with  ether  free  from  alcohol.  If  the  urobilin 
cannot  be  detected  by  the  above-described  methods,  then  precipi- 
tate the  urine  with  basic  lead  acetate,  decompose  the  precipitate 
with  acidified  alcohol,  test  this  solution  or  extract  the  coloring 
matter  by  dilating  with  water  and  shaking  with  chloroform. 

In  the  quantitative  estimation  of  urobilin  we  proceed  as  follows, 
according  to  G.  Hoppe-Seyler:  '  100  c.  c.  of  the  urine  are 
acidified  with  sulphuric  acid  and  saturated  with  ammonium  sul- 
phate. The  precipitate  is  collected  on  a  filter  after  some  time, 
washed  with  a  saturated  solution  of  ammonium  sulphate,  and 
repeatedly  extracted  with  equal  parts  alcohol  and  chloroform  after 
pressing.  The  filtered  solution  is  treated  with  water  in  a  separa- 
tory  funnel  until  the  chloroform  separates  well  and  becomes  clear. 
The  chloroform  solution  is  evaporated  on  the  water-bath  in  a 
weighed  beaker,  the  residue  dried  at  100°  C,  and  then  extracted 
with  ether.  The  ethereal  extract  is  filtered,  the  residue  on  the  filter 
dissolved  in  alcohol,  and  transferred  to  the  beaker  and  evaporated, 
then  dried  and  weighed.  According  to  this  method  Gr.  Hoppe- 
Setler  found  0.08-0.14  grm.  urobilin  in  one  day's  urine  of  a 
healthy  person,  or  an  average  of  0.123  grm. 

The  real  yellow  pigment  of  urine  has  been  only  slightly  investi- 
gated. This  pigment  has  been  called  urochrom  by  Garrod,' 
which  name  has  been  used  by  Thudichum  earlier  to  designate  a 
mixture  of  pigments  and  other  substances.  The  pigment  isolated 
by  Garrod  by  a  rather  complicated  method  was  amorphous  brown, 
very  easily  soluble  in  water  and  ordinary  alcohol,  less  soluble  in 
absolute  alcohol,  and  insoluble  in  ether,  chloroform,  and  benzol.  It 
shows  uo  absorption-bands,  and  does  not  fluoresce  on  the  addition 
of  ammonia  and  zinc  chloride. 

Uroerythrin  is  that  coloring  matter  which  often  colors  the  urinary  sedi- 
ment (sedimenium  lateritium)  beautifully  red.  It  occurs  especially  in  fevers 
and  other  diseases,  but  it  is  also  found  in  the  urine  of  perfectly  healthy  per- 
sons. Its  solution  is  colored  green  by  alkalies  and,  according  to  Zoja,^ 
shows  a  strong  absorption  beginning  between  D  and  E  and  extending  to  F. 
This  absorption  consists  of  two  bands,  of  which  the  one  at  F  is  the  stronger. 
Uroerythrin  dissolves  readily  in  amyl  alcohol.  Garrod*  has  suggested  a 
method  for  obtaining  uroerythrin,  and  has  given  further  contributions  for  the 
detection  of  the  same.  Attention  is  called  especially  to  the  well-known  prop- 
erty of  uroerythrin  of  being  bleached  on  exposure  to  light. 

'  Virchow's  Arch.,  Bd.  134. 

'  Proc.  of  Roy.  Soc,  Vol.  55,  1894.  See  also  Thudichum,  Brit.  Med.  Jour- 
nal, 1864,  Vol.  2;  Journal  f.  prakt.  Chem.,  Bd.  104. 

3  Arch.  ital.  di  clinica  med.,  1893;  alsoCentralbl.  f.  d.  med. Wissensch. ,  1892. 
*  Journal  of  Physiol.,  Vol.  17. 


CARBOHYDRATES  IN  THE   URINE.  505 

Volatile  fatty  acids,  such  as  formic  acid,  acetic  acid,  and  perhaps  also 
butyric  acid,  occur  under  normal  conditions  in  human  urine  (v.  Jaksch  '),  also 
in  that  of  dogs  and  herbivora  (Schotten'-').  The  acids  poorest  in  carbon,  such 
as  formic  acid  and  acetic  acid,  are  more  constant  in  the  body  than  those  richer 
in  carbon,  and  therefore  the  relatively  greater  part  of  these  pass  unchanged 
into  the  urine  (Schotten).  Normal  human  urine  contains  besides  these  bodies 
others  which  yield  acetic  acid  when  oxidized  by  potassium  dichromate  and  sul- 
phuric acid  (v.  JAKScn).  The  quantity  of  volatile  fatty  acids  in  normal  urine 
is,  according  to  V.  Jaksch,  0.008-0,009  grm.  per  24  hours,  and  according  to 
V.  RoKiTANSKY,'  0.054  grm.  The  quantity  is  increased  by  exclusive  farina- 
ceous food  (RoKiTANSKY),  also  in  fever  and  in  certain  diseases  of  the  liver 
(v.  Jaksch).  It  is  also  increased  in  leucaemia  and  in  many  cases  of  diabetes 
(v.  Jaksch).  Large  amounts  of  volatile  fatty  acids  are  produced  in  alkaline  fer- 
mentation of  the  urine,  and  the  quantity  is  6-15  times  as  large  as  in  normal 
urine  (Salkowski-*). 

Paral'tctic  Acid.  It  is  claimed  that  this  acid  occurs  in  the  urine  of  healthy 
persons  after  very  fatiguing  marches  (Colasanti  and  Moscatelli^).  It  is 
found  in  larger  amounts  in  the  urine  in  acute  phosphorus-poisoning  or  acute 
yellow  atrophy  of  the  liver  (Schultzex  and  RiESS^).  According  to  the  inves- 
tigations of  HoPPE  Seyler  and  Araki,'  lactic  acid,  besides  sugar,  passes  into 
the  urine  as  soon  as  the  supply  of  oxygen  is  decreased  in  any  way.  Minkowski  * 
has  shown  that  lactic  acid  occurs  in  the  urine  in  large  quantities  on  the  extir- 
pation of  the  liver  of  birds. 

Olycero-pJiosphorlc  arid  occurs  as  traces  in  the  urine,  and  it  is  probably  a 
decomposition  product  of  lecithin.  The  occurrence  of  succinic  acid  in  normal 
urine  is  the  subject  of  discussion. 

Carlohydrates  and  Reducmg  Substances  in  the  Urine.  The 
occurrence  of  grape-sugar  as  traces  iu  normal  urine  is  highly  prob- 
able, as  the  investigations  of  Brucke,  Abeles,  and  v.  Udranszky 
show.  The  last  investigator  has  also  shown  the  habitual  occurrence 
of  carbohydrates  in  the  urine,  and  their  presence  has  been  positively 
proved  by  the  investigations  of  Baumaxn  and  Wedexski,  and 
especially  by  Baisch.  Besides  glucose  normal  urine  contains, 
according  to  Baisch,  another  not  well-studied  variety  of  sugar, 
probably  isomaltose,  and  besides  this  a  dextrin-like  carbohydrate 
(animal  gum),  as  shown  by  Landwehr,  Wedenski,  and  Baisch.' 

Besides  traces  of  sugar  and  the  previously  mentioned  reducing 
substances,  uric  acid  and  creatinin,  the  urine  contains  still  other 
reducing  substances.     These  last  are  probably  (Fluckiger'")  con- 

>  Zeitschr.  f.  physiol.  Chem.,  Bd.  10. 
» Ibid.,  Bd.  7. 

*  Wien.  med.  Jahrb.,  1887;  cited  from  Maly's  Jahresber.,  Bd.  17. 

*  Zeitschr.  f.  physiol.  Chem.,  Bd.  13. 

*  Moleschott's  Untersuch.  zur  Naturlehre,  Bd.  14. 

*  Chem.  Centralbl. ,  1869. 

1  Zeitschr.  f.  physiol.  Chem.,  Bdd.  15,  16,  17,  and  19;  Irisawa,  ibid.,  Bd.  17, 
«  Arch.  f.  exp.  Path.  u.  Pharm.,  Bdd.  31  and  31. 

'  Zeitschr.  f.  physiol.  Chem.,  Bdd.   18,  19,  and  20;    Treupel,    ibid.,'  Bd.  16. 
These  articles  contain  references  to  the  work  of  other  investigators. 
'»  Zeitschr.  f.  physiol.  Chem.,  Bd.  9. 


506  THE   URINE. 

jugated  combinations  of  glycuronic  acid,  CJl^Jd.^.,  which  closely 
resembles  sugar.  The  reducing  power  of  normal  urine  corresponds, 
according  to  various  investigators,  to  1.5-5.96  p.  m.  grape-sugar.' 

Glycuronic  Acid,  C„H,„0,  or  CHO.(CH.OH),.COOH.  This 
acid  may  be  converted  into  saccharic  acid,  Q>^^,()^,  by  the  action 
of  bromine  (Thierfeldee'"),  and  it  seems  to  occupy  an  inter- 
mediate position  between  this  acid  and  gluconic  acid,  C^H^^O,.  It 
is  a  derivative  of  glucose,  and  Fischer  and  Piloty  '  have  prepared 
it  synthetically  by  the  reduction  of  saccharo-lactonic  acid.  Further 
reduction  yields  gulonic  acid  lacton  (Thierfeldee).  Glycuronic 
acid  is  an  intermediate  metabolic  product,  and  it  only  occurs  in  the 
urine  when  it  is  protected  from  combustion  in  the  animal  body  by 
combining  with  other  bodies.  Such  conjugated  combinations  with 
indoxyl,  skatoxyl,  and  phenols  occur  probably  normally  in  very 
small  quantities  in  human  nrine.  This  acid  as  conjugated  glycu- 
ronic acids  passes  in  large  quantities  into  the  urine  after  the  admin- 
istration of  various  therapeutic  agents  or  certain  other  substances. 
Thus  Schmiedeberg  and  Meter  ^  found  campho-glycuronic  acid 
in  the  urine  after  partaking  of  camphor,  and  v.  MEEiifG  ^  showed 
the  presence  of  urochloralic  acid  (see  Accidental  Constituents  of  the 
Urine)  after  the  administration  of  chloral  hydrate.  According  to 
Schmiedeberg, °  glycuronic  acid  seems  to  occur  in  cartilage  because 
it  is  contained  in  chondrosin,  a  cleavage  product  of  chondroitic- 
sulphuric  acid.  It  is  also  found  in  the  artist's  color  "  jaune 
indien,"  which  contains  the  magnesium-salt  of  euxanthonic  acid 
(euxanthon-glycuronic  acid).  On  heating  this  acid  with  water  to 
120-125°  C.  it  splits  into  euxanthin  and  glycuronic  acid,  and  it  is 
the  most  available  material  for  the  preparation  of  glycuronic  acid 
(Thierfeldee).  Another  acid,  isomeric  with  the  ordinary  glycu- 
ronic acid,  has  been  found  in  the  urine  in  certain  cases  (see  Acci- 
dental Constituents  of  the  Urine). 

Glycuronic  acid  is  not  crystalline,  but  is  obtained  only  as  a 
syrup.  It  dissolves  in  alcohol  and  is  easily  soluble  in  water.  If  the 
watery  solution  is  boiled  for  an  hour,  the  acid  is  in  part  (20^)  con- 

'  See  Huppert-jSfeubauer,  S.  72. 

*  The  works  of  Thierfelder  on  glycuronic  acid  are   found   in   Zeitschr.  f. 
physiol.  Chem.,  Bdd.  11,  13   and  15. 

3  Bar.  d.  deutscli.  cliem.  Gesellsch. ,  Bd.  24,  S.  521. 

••  Zeitsclir.  f .  pliysiol.  Chem. ,  Bd.  3. 

^  Ibid  ,  Bd.  6. 

«  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  28. 


OLJCUROmC  ACID.  50T 

verted  into  the  anhydride  glycuron,  0,HjOj,  which  is  crystalline, 
soluble  iu  water,  but  insoluble  in  alcohol.  The  alkali  salts  of  this 
acid  are  crystalline.  The  neutral  barium  salt  is  amorphous,  soluble 
in  water,  but  is  precipitated  by  alcohol.  If  a  concentrated  solution 
of  the  acid  is  saturated  with  barium  hydrate,  the  basic  barium  salt 
separates.  The  neutral  lead  salt  is  soluble  iu  water,  bat  the  basic 
salt  is,  on  the  contrary,  insoluble.  The  acid  is  dextrogyrate  and 
reduces  copper,  silver,  and  bismuth  salts.  It  does  not  ferment  with 
yeast.  Glycuronic  acid  gives  the  furfurol  reaction  and  acts  like  a 
pentose  when  tested  with  the  phloroglucin-hydrochloric-acid  test.. 
With  phenylhydrazin  potassium  glycuronate  gives  a  flaky  yellow 
precipitate  of  microscopic  needles  which  melt  at  114-115°  C. 
(Thierfelder).  The  statements  in  regard  to  the  behavior  of 
glycuronic  acid  with  this  test  are  very  contradictory.' 

All  conjugated  glycuronic  acids  are  Itevorotatory,  while  glycu- 
ronic acid  itself  is  dextrorotatory.  They  are  split  into  glycuronic 
acid  and  the  several  other  groups  by  the  addition  of  water.  A  few 
of  the  conjugated  glycuronic  acids,  such  as  the  urochloralic  acid, 
reduce  copper  oxide  and  certain  other  metallic  oxides  in  alkaline 
solution,  and  therefore  they  may  interfere  with  the  detection  of 
sugar  in  the  urine. 

Glycuronic  acid  may  be  prepared  from  urochloralic  acid  or 
campho-glycaronic  acid  by  boiliug  with  a  mineral  acid.  It  may  be 
prepared  more  easily  by  heating  euxanthonic  acid  with  water  iu 
Papix's  digester  to  120-125°  C.  for  an  hour  and  evaporating  the 
watery  solution  at  +  4:0°  C.  The  anhydride  which  crystallizes 
gradually  is  removed,  the  mother-liquor  diluted  with  water  and 
boiled  for  a  time  to  convert  a  second  portion  of  acid  into  anhydride, 
and  then  evaporated  at  about  +  40°  C.  This  is  continued  until 
nearly  all  the  acid  is  converted  into  anhydride.  The  anhydride 
may  then  be  further  purified. 

Organic  combinations  containing  sitlpJiur  of  nw^movfn  kind,  which  may  in 
small  part  cousist  of  sulphocyanides,  0.04  (Gscheidlen^)-O.  11  p.  m.  (I. 
MUNK),^  cystin,  or  bodies  related  to  it,  and  protein  bodies,  are  found  in  liuman 
as  well  as  in  animal  urines.  Lang*  has  shown  that  nitriles  of  tiie  fatty  series 
when  united  with  hydrocyanic  acid  in  the  animal  body  are  converted  into 
sulphocyanides,  and  pass  as  such  into  the  urine.  This  sulpchocyanide  orig- 
inates, it  seems,  from  the  readily  cleavable,  non-oxidizable  sulphur  of  the 
proteid  bodies,  which,  as  Paschkles  (ibid.)  has  shown,  readily  converts  potas- 

'  In  regard  to  literature  see  Hammarsten,  Zeitschr.  f.  physiol.  Chem.,  Bd. 
19,  S.  30,  and  Rocs,  ibid.,  Bd.  15,  S.  535. 
'  Pfliiger's  Arch.,  Bd.  14. 

*  Virchow's  Arch.,  Bd.  69. 

*  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  34. 


508  THE    URINE. 

slum  cyanide  into  alkali  sulpbocyanide  in  an  alkaline  reaction  and  at  tlie  tem- 
perature of  the  body.  The  amido-acids  of  the  fatty  series  in  the  body  are 
probably  oxidized  to  nitriles,  which  are  then  transformed  into  sulphocyauides 
by  the  sulphur  of  the  proteids.  The  sulphur  of  these  mostly  unknov.'n  com- 
binations has  been  called  "neutral,"  to  differentiate  it  from  the  "  acid  "  sulphur 
of  the  sulphate  and  ethereal-sulphuric  acids  (Salkowski  ').  The  neutral  sulphur 
in  normal  urine  as  determined  by  Salkowski  is  lb%,  by  Siadthagen  ^  13.3- 
14.5/»,  and  by  Lepine^  20^  of  the  total  sulphur.  In  starvation,  according  to 
Fr.  MiJLLER,*  the  absolute  and  relative  quantities  increase.  According  to 
Heffter^  the  quantity  is  greater  with  a  bread  diet  than  with  a  meat  diet. 
Excessive  muscular  exercise  increases  the  elimination  of  the  acid  as  well  as  the 
neutral  sulphur;  still,  according  to  Beck  and  Benedikt,*  the  increase  in  neutj  al 
sulphur  takes  place  earlier.  According  to  Presch  ■"  sulphur  when  introduced  in 
the  body  increases  the  elimination  of  neutral  sulphur;  indeed,  about  one  fourth 
of  the  sul])hur  absorbed  in  the  elementary  state  passes  into  organic  combinations, 
not  oxidizable  by  nitric  acid  alone.  According  to  the  investigations  of  W. 
Smith*  it  is  probable  that  the  most  unoxidizable  part  of  the  neutral  sulphur 
occurs  as  sulpho-acids.  An  increased  elimination  of  neutral  sulphur  has  been. 
observed  in  various  diseases,  such  as  pneumonia,  icterus,  and  cystiuuria. 

The  total  quantity  of  sulphur  in  the  urine  is  determined  by  fusing  the  solid 
urinary  residue  with  saltpetre  and  caustic  alkali.  The  quantity  of  neutral 
sulphur  is  deterunned  as  the  difference  between  the  total  sulphur  and  the 
sulphur  of  the  sulphate  and  ethereal-sulphuric  acids. 

SulpJiuretted  hydrogen  occurs  in  urine  only  under  abnormal  conditions  or 
as  a  decomposition  product.  Sulphuretted  hydrogen  may  be  produced  from 
the  neutral  sulphur  of  the  organic  substances  of  the  urine  by  the  action  of 
■certain  bacteria  (Fr.  Mullek,^  Salkowski''*).  Other  investigators  have  given 
hypi/sulpliites  as  the  source  of  the  sulphuretted  hydrogen.  The  occurrence  of 
hyposulphites  in  normal  human  urme,  which  is  asserted  by  Heffter,''  is 
disputed  by  Salkowski'*  and  Presch.'^  Hyposulphites  occur  constantly  in 
cat's  urine  and,  as  a  rule,  also  in  dog's  urine. 

Organic  cumbinations  containing  phosphorus  (glycero-phosphoric  acid,  etc.), 
which  yield  phosphoric  sicid  on  tusing  with  saltpetre  and  caustic  alkali,  are 
also  found  in  urine  (Lepine,  Etmonnet,  and  Atjbert'-*). 

Enzymes  of  various  kinds  have  been  isolated  from  the  urine.  Among  these 
we  may  mention  pepsin  (Brdcke  '*  and  others),  diastatic  enzyme  (Cohnheim  '* 
and  others).     The  occurrence  of  rennin  and  trypsin  in  the  urine  is  doubtful.'-' 

'  Virchow's  Arch.,  Bd.  58,  and  Zeitschr.  f.  physiol.  Chem  ,  Bd.  9. 

2  Virchow's  Arch.,  BJ.  100. 

*  Compt.  rend.,  Tomes  91  and  97. 

4  Berlin,  klin.  Wochenschr.,  1887. 

'=  PflUger's  Arch.,  Bd.   38. 

«  Maly's  Jahresber.,  Bd.  22,  S.  223. 

•>  Virchow's  Arch.,  Bd.  119. 

8  Zeitschr.  f.  physiol.  Chem.,  Bd.  17. 

9  Berlin,  klin.  Wochenschr.,  1887. 
10  Ibid.,  1888. 

"  Pflilger's  Arch.,  Bd.  38. 

"  Ibid.,  Bd.  39. 

"  Virchow's  Arch.,  Bd.  119. 

'*  Compt.  rend..  Tome  98,  and  Compt.  rend." de  la  soc.  de  Biol.,  1882  and 
1884. 

'^  Wien.   Sitzungsber.,  Bd.  43. 

'«  Virchow's  Arch..  Bd.  28. 

"  In  regard  to  the  literature  on  enzymes  in  the  urine  see  Huppert-Neu- 
bauer,  p.  599. 


INORGANIC  CONSTITUENTS   OF  URINE.  509 

Substances  simi'ar  to  mucin  (nucleoalbamin  ?)  from  the  iii  inary  passages  and 
the  bladder  are  generally  present  in  the  urine,  though  in  very  small  quantities. 
According  to  several  investigators  normal  human  urine  also  contaiiis  traces  of 
protcid. 

Ptomaines  and  leucomaines  or  poisonous  substances  of  an  unknown  kind, 
which  are  often  described  as  alkaloidal  substances,  occur  in  normal  ur.ne 
(PoucHET,  Bouchard,  Aducco,  and  others).  Under  pathological  conditions 
the  quantity  of  these  substances  may  be  increased  (Bouchard,  Lepine  and 
GuERix,  ViLLiERS,  and  oihers).  Within  the  last  few  years  the  poisonous 
properties  of  urine  have  bi-en  the  subject  of  more  thorough  investigation, 
especially  by  Bouchard.  He  found  that  the  night  urine  is  less  poi.sonous 
than  theday  urine,  and  that  the  poisonous  constituents  of  the  day  and  night 
urines  have  not  the  same  action.  In  order  to  be  able  to  compare  the  toxidity 
of  the  urine  under  different  conditions,  Bouchard  determines  the  UROTOXIC 
COEFFFCiEXT,  which  Is  the  weight  of  rabbit  in  kilos  which  is  killed  by  the 
quantity  of  urine  excreted  by  one  kilo  of  the  person  experimented  upon  in 
24  hours.' 

Baujiaxx  and  v.  Udranszkt  '  have  shown  that  ptomaines  may  occur  in 
the  urine  under  pathological  conditions.  They  demonstrated  the  presence  of 
the  two  p  omaines  discovered  and  first  isolated  by  Brieger — putrescine, 
C4H12X2  (^tetramethylendiamin),  and  cadnverin,  C5H14N2  (pentamethyiendi- 
amin) — in  the  urine'of  a  patient  suffering  from  cystiuuria  and  catarrh  of  the 
bladder.  Cadaverin  has  later  been  found  by  Stadthagex  and  Bkieger  ^  in 
the  urine  in  two  cases  of  cystinurin. 

Brieger,  v.Udranszky  and  Baumanx^  and  Stadthagen  have  shown  that 
not  only  these  but  other  diamins  occur  under  physiological  conditions.  The 
occurrence  in  normal  urine  of  any  "  urine  poison  "  is  denied  by  certain  investi- 
gators, su;h  as  Stadtiiagex.'*  The  poisonous  action  of  the  urine,  according 
to  them,  i^  due  in  part  to  the  potas.-ium  salts  and  in  part  to  the  sum  of  the 
toxidity  of  the  other  normal  urinary  constituents  (urea,  creatinin,  etc.),  which, 
have  verv  little  poi-onous  action  individually. 

Many  substances  have  been  observed  in  animal  urine  which  are  not  found 
in  human  urine.  To  these  belong:  kynurenic  acid,  C'ioHtNOs  ,  which  is  an 
oxychinolincarbonic  acid,  occurring  in  dog's  urine  ;  urocanic  acid,  found  in 
dog's  urine ;  danialuric  acid  and  damolic  acid  (according  to  Schotten  * 
probably  a  mixture  of  benzoic  acid  with  volatile  fatty  acids),  obtained  by  the 
distillation  of  cow's  urine  ;  and  lastly  lithuric  acid,  found  in  the  urinary  con- 
crements  of  certain  animals. 

III.  Inorganic  Constituents  of  Urine. 

Chlorides.  The  chlorine  occurring  iu  urine  is  nndonbtedly 
combined  with  the  bases  contained  in  this  excretion ;  the  chief  part 
is  combined  with  sodium.  In  accordance  with  this,  the  quantity  of 
chlorine  in  the  urine  is  generally  expressed  as  ISTaCl. 

The  quantity  of  chlorine  combinations  in  the  urine  is  subject  to 
considerable  variation.     In  general  the  qiiantity  for  a  healthy  adult 

'  A  complete  bibliography  on  ptomaines  and  leucomaines  in  tlie  urine  is 
found  in  Huppert-Neubauer,  p,  403.  See  also  Griffiths,  Compt.  rend.,  Tomes 
113,  114.  and  115,  on  ptomaines  in  the  urine  in  difEerent  infectious  diseases. 

*  Zeitschr.  f.  physiol.  Chem.,  Bd.  13. 

*  Virchovv's  Arch.,  Bd.  115. 
♦Zeitsclir.  f.  klin.  Med.,  Bd.  15. 

'  Zeitschr.  f.  physiol.  Chem.,  Bd.  7. 


510  THE   URINE. 

on  a  mixed  diet  is  10-15  grms.  NaCl  per  24  hours.  The  quantity 
of  common  salt  in  the  urine  depends  chiefly  upon  the  quantity  of 
salt  in  the  food,  with  which  the  elimination  of  chlorine  increases 
and  decreases.  The  free  drinking  of  water  also  increases  the 
elimination  of  chlorine,  which  is  greater  during  activity  than  during 
rest  (at  night).  Certain  organic  chlorine  combinations,  such  as 
chloroform,  may  increase  the  elimination  of  inorganic  chlorides  by 
the  urine  (Zellek,'  Mylius,  Kast''). 

Iq  diarrhoea,  in  quick  formation  of  large  transudations  and 
exudations,  also  in  specially-marked  cases  of  acute  febrile  diseases 
at  the  time  of  the  crisis,  the  elimination  of  common  salt  is  materi- 
ally decreased.  The  elimination  is  abnormally  increased  in  the 
first  days  after  the  crisis  and  during  the  absorption  of  extensive  exu- 
dations. A  diminished  elimination  of  chlorine  is  found  in  disturbed 
absorption  in  the  stomach  aad  intestine,  and  in  acute  and  chronic 
diseases  of  the  kidneys  accompauied  with  albuminuria.  In  chronic 
diseases  the  elimination  of  chlorine  in  general  keeps  pace  with  the 
nutritive  condition  of  the  body  and  the  activity  of  the  secretion  of 
the  urine.  As  under  physiological  conditions  the  quantity  of 
common  salt  taken  with  the  food  has  the  greatest  influence  on  the 
eliminatiou  of  NaCl  in  disease 

The  quantitative  estimation  of  chlorine  in  urine  is  most  simply 
performed  by  titration  with  siWer-nitrate  solution.  The  urine  must 
not  contain  either  proteid  (which  if  present  must  be  removed  by 
coagulation)  or  iodine  or  bromine  compounds. 

In  the  presence  of  bromides  or  iodides  evaporate  a  measured  qiiantity  of  tlie 
urine  to  dryut-ss,  fuse  the  residue  witli  saltpetre  and  sodi,  dis  olve  the  fused 
m;  ss  in  water,  and  remove  the  iodine  or  bromine  by  the  addition  of  dilute  sul- 
pliuric  acid  and  some  nitrite,  and  thoroughly  shake  with  carbon  disulphide. 
The  liquid  thus  <  btained  may  now  be  titrated  with  silver  nitiate  according  to 
Yolhaud's  metliotl.  Tlie  quantity  of  bromide  or  iodide  is  calculated  as  the 
difference  between  the  quantity  of  silver-nitrate  solution  used  for  the  titration 
of  th  solution  of  the  fusi^d  mass  and  the  quantity  used  for  the  corresponding 
volume  of  the  original  urine. 

The  otherwise  excellent  titration  method  of  Mohe,  according 
to  which  we  titrate  with  silver  nitrate  in  neutral  liquids,  using 
neutral  potassium  chromate  as  an  indicator,  cannot  be  used  directly 
on  the  urine  in  careful  work.  Organic  urinary  constituents  are  also 
precipitated  by  the  silver-salt,  and  the  results  are  therefore  some- 
what high  for  the  chlorine.  If  we  wish  to  use  this  method,  the 
organic  urinary  constituents  must  first  be  destroyed.  For  this  pur- 
pose evaporate  to  dryness  5-10  c.  c.  of  the  urine,  after  the  addition 
of  1  grm.  of  chlorine-free  soda  and  1-2  grms.  chlorine-free  salt- 

'  Zeitscbr.  f.  physiol.  Cham.,  Bd.  8. 

^Ibid..  Bd.  11. 


CHLORIDES.  511 

petre,  and  carefally  fuse.     The  mass  is  dissolved  in  water,  acidified 

faintly  with  nitric  acid,  and  then  neutralized  exactly  with  pure 

lime  carbonate.     This  neutral  solution  is  used  for  the  titration. 

N 
The  silver-nitrate  solution  may  be  a  -—  solution.     It  is  often 

''  10 

made  of  such  a  strength  that  each  c.  c.  corresponds  to  0.006  grm. 

CI    or   0.01   grm.    NaCl.     This   last-mentioned   solution    contains 

29.075  grms.  AgNO,  in  1  litre. 

Freund  and  Toepffer  '  have  modified  this  method  in  that  they 
titrate  with  silver  nitrate  in  acetic-acid  solution,  which  prevents 
the  precipitation  of  the  silver  combinations  of  uric  acid,  xanthin 
bases,  etc.  Dilute  5  or  10  c.  c.  of  the  urine  with  25  c.  c.  water, 
add  2.5  c,  c.  of  a  solution  of  acetic  acid  and  sodium  acetate  (3^ 
acid  and  10^  sodium  acetate),  and  titrate  after  the  addition  of 
potassium  chromate.  Another  modification  has  recently  been  sug- 
gested by  BODTKER." 

Volhard's  Method.  Instead  of  the  preceding  determination, 
Volhard's  method,  which  can  be  performed  directly  on  the  urine, 
may  be  employed.  The  principle  is  as  follows:  All  the  chlorine 
from  the  urine  acidified  with  nitric  acid  is  precipitated  by  an  excess 
of  silver  nitrate,  filtered,  and  in  a  measured  part  the  quantity  of 
silver  added  in  excess  is  determined  by  means  of  a  sulphocyanide 
solution.  This  excess  of  silver  is  completely  precipitated  by  the 
sulphocyanide  and  a  solution  of  some  ferric  salt,  which,  as  is  well 
known,  gives  a  blood-red  reaction  with  the  smallest  quantity  of 
sulphocyanide,  is  used  as  an  indicator. 

We  require  the  following  solutions  for  this  titration:  1.  A  silver- 
nitrate  solution  which  contains  29.075  grms.  AgNOg  per  litre  and 
of  which  each  c.  c.  corresponds  to  0.01  grm.  NaCl  or  0.00607  grm. 
CI;  2.  A  saturated  solution  at  the  ordinary  temperature  of  chlorine- 
free  iron  alum  or  ferric  sulphate;  3.  Chlorine-free  nitric  acid  of  a 
specific  gravity  of  1.2;  4.  A  potassium-sulphocyanide  solution 
which  contains  8.3  grms.  KCNS  per  litre,  and  of  which  2  c.  c. 
corresponds  to  1  c.  c.  of  the  silver-nitrate  solution. 

About  9  grms.  of  potassium  sulphocyanide  are  dissolved  in  water  and  diluted 
to  one  litre.  Tije  quantity  of  KCNS  ccmtained  in  this  solution  is  determined  l)y 
the  silver-nitrate  solution  in  the  following;  way:  Measure  exactly  10  c  c  of 
the  silver  solution  and  treat  with  5  c.  c.  of  nitric  acid  and  1-3  c.  c.  of  the  ferric- 
salt  solution,  and  dilute  with  water  ti  about  100  c.  c.  Now  the  sulphocyanide 
solution  is  added  from  a  burette,  constantly  stirring,  until  a  permanent  faint 
red  coloration  of  the  liquid  takes  place.  The  quantity  of  sulpliocyanide  found 
in  the  solution  by  this  means  indicates  how  much  it  must  he  diluted  to  lie  of 
the  proper  strength.  Titrate  once  more  with  10  c  c.  AgNOs  solution  and  cor- 
rect the  sulphocyanide  solution  by  the  careful  addition  of  water  until  30  c.  c. 
exactly  correspond  to  10  c.  c.  of  the  silver  solution. 

The  determination  of  the  chlorine  in  the  urine  is  performed  by 

'  Centralbl.  f.  klin.  Med.,  Bd  13,  No.  38.  Cited  from  Maly's  Jahresber., 
Bd.  23,  S.  325. 

«  Zeitscbr.  f   physiol.  Chem.,  Bd.  20. 


512  THE   URINE. 

this  method  in  the  following  way:  Exactly  10  c.  c.  of  the  urine  are 
placed  in  a  flask  which  lias  a  mark  corresponding  to  100  c.  c. ; 
5  c.  c.  nitric  acid  are  added ;  dilate  with  about  50  c.  c.  water,  and 
then  allow  exactly  20  c.  c.  of  the  silver-nitrate  solution  to  flow  in. 
Close  the  flask  with  the  thumb  and  shake  well,  slide  off  the  thumb 
and  wash  it  with  distilled  water  into  the  flask,  and  fill  the  flask  to 
the  100-c.  c.  mark  with  distilled  water.  Close  again  with  the 
thumb,  carefully  mix  by  shaking,  and  filter  through  a  dry  filter. 
Measure  off  50  c.  c.  of  the  filtrate  by  means  of  a  dry  pipette,  add 
3  c.  c.  ferric-salt  solution,  and  allow  the  sulphocyanide  solution  to 
flow  in  until  the  liquid  above  the  precipitate  has  a  permanent  red 
color.  The  calculation  is  very  simple.  Eor  example,  if  4.6  c.  c. 
of  the  sulphocyanide  solution  were  necessary  to  produce  the  flnal 
reaction,  then  for  100  c.  c.  of  the  filtrate  (=10  c.  c.  urine)  9.3 
c.  c.  of  this  solution  are  necessary.  9.2  c.c.  of  the  sulphocyanide 
solution  corresponds  to  4.6  c.  c.  of  the  silver  solution,  and  since 
20  —  4.6  =  15.4  c.  c.  of  the  silver  solution  were  necessary  to  com- 
pletely precipitate  the  chlorides  in  10  c.  c.  of  the  urine,  then  10 
c.  c.  contain  0.154  grm.  NaCl.  The  quantity  of  sodium  chloride  in 
the  urine  is  therefore  1.54^  or  15.4 "/oo-  If  we  always  use  10  c.  c. 
for  the  determination,  and  always  20  c.  c.  AgNOj,  and  dilute  with 
water  to  100  c.  c,  we  find  the  quantity  of  NaCl  in  1000  parts  of  the 
urine  by  subtracting  the  number  of  c.  c.  of  sulphocyanide  (E) 
required  with  50  c.  c.  of  the  filtrate  from  20.  The  quantity  of 
NaCl  p.  m.  is  therefore  under  these  circumstances  =  20  —  R,  and 

the  percentage  of  NaCl  =  — — — . 

The  approximate  estimation  of  chlorine  in  the  urine  (which 
must  be  free  from  proteid)  is  made  by  strongly  acidifying  with 
nitric  acid  and  then  adding  to  it,  drop  by  drop,  a  concentrated 
silver-nitrate  solution  (1  :  8).  In  a  normal  quantity  of  chlorides  the 
drop  sinks  to  the  bottom  as  a  rather  compact  cheesy  lump.  In 
diminished  quantities  of  chlorides  the  precipitate  is  less  compact  and 
coherent,  and  in  the  presence  of  very  little  chlorine  a  fine  white 
precipitate  or  only  a  cloudiness  or  opalescence  is  obtained. 

Phosphates.  Phosphoric  acid  occurs  in  acid  urines  partly  as 
double-,  MH.^PO^,  and  partly  as  simple-acid,  M^HPO^,  phosphates, 
both  of  which  are  found  in  acid  urines  at  the  same  time.  Ott  ' 
found  that  on  an  average  60^  of  the  total  phosphoric  acid  was 
double-  and  40^  was  simple-acid  phosphate.  The  total  quantity  of 
phosphoric  acid  is  very  variable  and  depends  on  the  kind  and  the 
quantity  of  food.  The  average  quantity  of  P,0^  is  in  round  num- 
bers 2.5  grms.,  with  a  variation  of  1-5  grms.,  per  24  hours.  A 
small  part  of  the  phosphoric  acid  of  the  urine  originates  from  the 

1  Zeitschr.  f.  plijsiol.  Cliem.,  Bd.  10. 


PHOSPHATES.  513 

"baming  of  organic  componnds,  nnclein,  protagon,  and  lecithin, 
within  the  organism.  The  greater  part  originates  from  the  phos- 
phates of  the  food,  and  the  quantity  of  eliminated  phosphoric  acid 
is  greater  when  the  food  is  rich  in  alkali  phosphates  in  proportion 
to  the  quantity  of  lime  and  magnesia  phosphates.  If  the  food 
contains  much  lime  and  magnesia,  large  quantities  of  earthy  phos- 
phates are  eliminated  by  the  excrements;  and  eren  though  the  food 
contains  considerable  amounts  of  phosphoric  acid  in  these  cases,  the 
quantity  of  phosphoric  acid  in  the  urine  is  small.  Such  a  condition 
is  found  in  herbivora,  whose  urine  is  habitually  poor  in  pliosphates. 
The  extent  of  the  elimination  of  phosphoric  acid  by  the  urine 
depends  not  only  upon  the  total  quantity  of  phosphoric  acid  in  the 
food,  but  also  upon  the  relative  amounts  of  alkaline  earths  and  the 
alkali  salts  in  the  food.  According  to  Preysz,'  Olsavsky  and 
Klug  '  the  elimination  of  phosphoric  acid  is  considerably  increased 
by  intense  muscular  work. 

From  the  transformation  of  tissues  rich  in  proteid  or  of  phos- 
phorized  nerve-substance  in  the  body  we  might  perhaps  expect  an 
equal  relation  between  the  nitrogen  and  the  phosphoric  acid  in  the 
urine.  Many  investigations  have  been  made  upon  this  subject,  but 
as  all  the  conditions  which  affect  the  elimination  of  phosphoric  acid 
are  not  yet  sufficiently  known,  it  is  difficult  to  draw  any  definite 
couciusions  from  the  observations  thus  far  made. 

As  the  extent  of  the  elimination  of  phosphoric  acid  is  mostly 
dependent  upon  the  character  of  the  food  and  the  absorption  of  the 
phosphates  in  the  intestine,  it  is  apparent  that  the  relationship 
between  the  nitrogen  and  phosphoric  acid  in  tlie  urine  can  only  be 
approximately  constant  with  a  certain  uniform  food.  Thus,  on 
feeding  with  exclusive  meat  diet,  as  observed  by  Voit^  on  dogs, 
when  the  nitrogen  and  phosphoric  acid  (P,OJ  of  the  food  exactly 
reappeared  in  the  urine  and  feeces  the  relationship  was  8.1  :  1.  In 
starvation  this  relationship  is  changed,  namely,  relatively  more  phos- 
phoric acid  is  eliminated,  which  seems  to  indicate  that  besides  flesh 
and  related  tissues  also  another  tissue  rich  in  phosphorus  is  largely 
destroyed.  The  starvation  experiments  show  that  this  tissue  is 
the  bone  tissue. 

'  SeeMaly's  Jahresber.,  Bd.  21. 

*  Pfliiger's  Arch. ,  Bd.  54. 

*  Pliysiologie    des    allgemeinen    StofEwechsels  und  der  Ernabrung   in   L, 
Hermann's  Handbucb,  Bd.  6,  Thl.  1,  S.  79. 


514  THE   URINE. 

Little  is  known  in  regard  to  the  elimination  of  phosphoric  acid 
in  disease.  In  febrile  diseases,  as  shown  by  several  observations, 
the  quantity  of  phosphoric  acid  as  compared  with  the  nitrogen  is  con- 
siderably decreased.  In  diseases  of  the  kidneys  the  activity  of  these 
organs  in  eliminating  the  phosphates  may  be  considerably  dimin- 
ished (Fleischer  ').  In  meningitis,  on  the  contrary,  a  marked 
increase  in  the  phosphates  is  observed  in  the  urine.  Teissiee  has 
described  a  special  form  of  polyuria,  in  which  large  quantities 
of  earthy  phosphates,  10-20-30  grms.  per  24  hours,  were  eliminated. 
This  polyuria  was  called  phosphate  diabetes  "  by  Teissier.  The 
statements  in  regard  to  the  quantity  of  phosphate  in  the  urine  in 
rachitis  and  in  osteomalacia  are  somewhat  contradictory.^ 

Qucmtitative  estimation  of  pJiosptioric  acid  in  the  urine.  This 
estimation  is  most  simply  performed  by  titrating  with  a  solution  of 
nraniam  acetate.  The  principle  of  the  titration  is  as  follows:  A 
warm  solution  of  phosphates  containing  free  acetic  acid  gives  a 
whitish-yellow  precipitate  of  uranium  phosphate  with  a  solution  of 
a  uranium  salt.  This  precipitate  is  insoluble  in  acetic  acid,  but 
dissolves  in  mineral  acids,  and  on  this  account  we  always  add  in 
titrating  a  certain  quantity  of  sodium-acetate  solution.  Potassium 
ferrocyanide  is  used  as  the  indicator,  which  does  not  act  on  the 
araniuni-phosphate  precipitate,  but  gives  a  reddish-brown  precipi- 
tate or  coloration  in  the  presence  of  the  smallest  amount  of  soluble 
uranium  salt.  The  solutions  necessary  for  the  titration  are:  1.  A 
solution  of  a  uranium  salt  of  Avhich  each  c.  c.  corresponds  to  0.005 
grm.  PjOj  and  which  contains  20.3  grms.  uranium  oxide  per  litre. 
20  c.  c.  of  this  solution  corresponds  to  0.100  grm.  P^O^.  2.  A 
solution  of  sodium  acetate;  3.  A  freshly  prepared  solution  of  potas- 
sium ferrocyanide. 

Tbe  uranium  solution  is  prepared  from  uranium  nitrate  or  acetate.  Dissolve 
about  35  grms.  uranium  acetate  in  water,  add  some  acetic  acid  to  facilitate 
solution,  and  dilute  to  one  litre.  Tbe  strength  of  this  solution  is  determined 
by  titrating  with  a  solution  of  sodium  pho.sphate  of  known  str^  ngth  (10.085 
grms  crystallized  salt  in  1  litre,  which  corresponds  to  0.100  grm.  PjOj  in  50 
c.  c).  Proceed  in  the  same  way  as  in  the  titration  of  the  urine  (see  below)^ 
and  correct  the  solution  by  diluting  with  water,  and  titrate  again  until  20  c.  c. 
of  the  uranium  solution  corresponds  exactly  to  50  c.  c.  of  the  above  phosphate 
solution. 

The  sodium-acetate  solution  should  contain  10  grms.  sodium  acetate  and  10 
grms.  cone  acetic  acid  in  KiO  c.  c.  For  each  titration  5  c.  c.  of  this  solution  is 
used  with  50  c    c.  of  the  urine. 

In  performing  the  titration,  mix  50  c.  c.  of  filtered  urine  in  a 
beaker  with  o  c.  c.  of  the  sodium  acetate,  cover  the  beaker  with  a 

'  Deutsch.  Arch.  f.  klin.  Med.,  Bd.  29. 
2  Centralbl.  f.  d.  med.  Wissensch.,  1877. 

2  In  regard  to  the  eliminatifin  of  phosphates  in  disease  see  Neubauer-Hup- 
pert-T];omas,  Harnanalyse,  9.  Aufl.,  Semiotischer  Theil,  S.  255-267. 


SULPILATEti.  615 

watch-glass,  and  warm  over  the  water-bath.  Then  allow  the 
uranium  solution  to  flow  in  from  a  burette,  and,  when  the  precipi- 
tate does  not  seem  to  increase,  place  a  drop  of  the  mixture  on  a 
porcelain  plate  with  a  drop  of  the  potassium-ferrocyanide  solution. 
If  the  amount  of  uranium  solution  employed  is  not  sufficient,  the 
color  remains  pale  yellow  and  more  uranium  solution  must  be 
added;  but  as  soon  as  the  slightest  excess  of  uranium  solution  has 
been  used,  the  color  becomes  faint  reddish  brown.  When  this 
point  has  been  obtained,  warm  the  solution  again  and  add  another 
drop.  If  the  color  remains  of  the  same  intensity,  the  titration  is 
ended;  but  if  the  color  varies,  add  more  uranium  solution,  drop  by 
drop,  until  a  permanent  coloration  is  obtained  after  warming,  and 
now  repeat  the  test  with  another  50  c.  c.  of  the  urine.  The  cal- 
culation is  so  simple  that  it  is  unnecessary  to  give  an  example. 

In  the  above  manner  we  determine  the  total  quantity  of  phos- 
phoric acid  in  the  urine.  If  we  wish  to  know  the  phosphoi'ic  acid 
combined  with  alkaline  earths  or  with  alkalies,  we  first  determine 
the  total  phosphoric  acid  in  a  portion  of  the  urine  and  then  remove 
the  earthy  phosphates  in  another  portion  by  ammonia.  The  pre- 
cipitate is  collected  on  a  filter,  washed,  transferred  in  a  beaker  with 
water,  treated  with  acetic  acid,  and  dissolved  by  warming.  This 
solution  is  now  diluted  to  50  c.  c.  with  water,  and  5  c.  c.  sodium- 
acetate  solution  added,  and  titrated  with  uranium  solution.  The 
ditference  between  the  two  determinations  gives  the  quantity  of 
phosphoric  acid  combined  with  the  alkalies.  The  results  obtained 
are  not  quite  accurate,  as  a  partial  transformation  of  the  monophos- 
phates of  the  alkaline  earths  and  also  calcium  dipliosphate  into 
triphosphates  of  the  alkaline  earths  and  ammonium  phosphate  takes 
place  on  precipitating  with  ammonia,  which  gives  too  high  results 
for  the  phosphoric  acid  combined  with  alkalies  remaining  in  solu- 
tion. 

Sulphates.  The  sulphuric  acid  of  the  urine  originates  only  to 
a  very  small  extent  from  the  sulphates  of  the  food.  A  dispropor- 
tionally  greater  part  is  formed  by  the  burning  of  the  proteids  con- 
taining sulphur  within  the  body,  and  it  is  chiefly  this  formation  of 
sulphuric  acid  from  the  proteids  which  gives  rise  to  the  previously 
mentioned  excess  of  acids  over  the  bases  in  the  urine.  The  quantity 
of  sulphuric  acid  eliminated  by  the  urine  amounts  to  about  2.5 
grms.  H,SO^  per  twenty-four  hours.  As  the  sulphuric  acid  chiefly 
originates  from  the  proteids,  it  follows  that  the  elimination  of 
sulphuric  acid  and  the  elimination  of  nitrogen  are  nearly  parallel, 
and  the  relationship  N  :  II^SO^  is  about  5:1.  A  complete  parallel- 
ism can  hardly  be  expected,  as  in  the  first  place  a  part  of  the  sulphur 
is  always  eliminated  as  neutral  sulphur,  and  secondly  because  the 
low    quantity    of   sulphur   in   different   protein    bodies    undergoes 


516  THE    URINE. 

greater  variation  as  compared  with  the  high  quantity  of  nitrogen  con- 
tained therein.  Generally  the  relationship  between  the  elimination 
of  nitrogen  and  sulphuric  acid,  under  normal  and  diseased  condi- 
tions, runs  rather  parallel.  Sulphuric  acid  occurs  in  the  urine 
partly  preformed  (sulphate-sulphuric  acid)  and  partly  as  ethereal- 
sulphuric  acid.  The  first  is  designated  as  A-  and  the  other  as. 
^-sulphuric  acid. 

The  quantity  of  total  sulphuric  acid  is  determined  in  the  follow- 
ing way,  but  at  the  same  time  the  precautions  described  in  other 
works  must  be  observed:  100  c.  c.  of  filtered  urine  are  treated  with 
5  c.  c.  concentrated  hydrochloric  acid  and  boiled  for  fifteen  minutes. 
While  boiling  precipitate  with  2  c.  c.  of  a  saturated  BaCl^  solution 
and  warm  for  a  little  while  until  the  barium  sulphate  has  completely 
settled.  The  precipitate  must  then  be  washed  with  water  and  also 
with  alcohol  and  ether  (to  remove  resinous  substances)  and  then 
treated  according  to  the  usual  method. 

The  separate  determination  of  the  sulphate-sulphuric  acid  and 
the  ethereal-sulphuric  acid  may  be  accomplished,  according  to 
Baumakjst's  '  method,  by  first  precipitating  the  sulphate-sulphuric 
acid  from  the  urine  acidified  with  acetic  acid  by  BaCl^,  and  then 
decomposing  the  ethereal-sulphuric  acid  by  boiling  after  the  addi- 
tion of  hydrochloric  acid,  and  then  determining  the  sulphuric 
acid  set  free  as  barium  sulphate.  A  still  better  method  is  the 
following  suggested  by  Salkowski': 

200  c.  c.  of  urine  are  precipitated  by  an  equal  volume  of  a. 
barium  solution  which  consists  of  2  vols,  barium  hydrate  and  1  vol. 
barium-chloride  solution,  both  saturated  at  the  ordinary  tempera- 
ture. Filter  through  a  dry  filter,  measure  off  100  c.  c.  of  the 
filtrate  which  contains  only  the  ethereal-sulphuric  acid,  treat  with 
10  c.  c.  hydrochloric  acid  of  a  specific  gravity  1.12,  boil  for  fifteen 
minutes,  and  then  warm  on  the  water-bath  until  the  precipitate  has 
completely  settled  and  the  supernatant  liquid  is  entirely  clear. 
Filter  and  wash  with  warm  water  and  with  alcohol  and  ether  and 
proceed  according  to  the  generally  prescribed  method.  The  differ- 
ence between  the  ethereal-sulphuric  acid  found  and  the  total 
quantity  of  sulphuric  acid  as  determined  in  a  special  portion  of 
urine  is  considered  as  the  quantity  of  sulphate-sulphuric  acid. 

Nitrates  occur  in  small  quantities  in  human  urine  (Schonbein  '),  and  tlaej' 
probably  oriu^inate  from  the  drinking-water  and  tlie  lood.  According  to> 
Weyl  and  Citron,*  the  quantity  of  nitrates  is  smallest  with  a  meat  diet  and 
greatest  with  vegetable  food.  The  average  amount  is  about  43.5  milligrammes 
per  litre. 

•  Zeitschr.  f.  physiol.  Chem.,  Bd,  1,  S.  70. 
«  Virchow's  Arch.,  Bd.  79. 

»  Journ.  f.  prakt.  Chem.,  Bd.  93,  S.  153. 

*  Virchow's  Arch.,  Bdd.  96  u.  101. 


AMMONIA.  517 

Potassium  and  Sodium.  The  quantity  of  these  bodies  eliminated 
by  the  urine  by  a  healthy  full-grown  person  on  a  mixed  diet  is, 
according  to  Salkowski,'  3-4:  grnis.  K.^0  and  5-8  grms.  Na.,0,  with 
an  average  of  about  2-3  grms.  K^O  and  4-6  grms.  Na^O.  The 
proportion  of  K  to  Na  is  ordinarily  as  3:5.  The  quantity 
depends  above  all  upon  the  food.  In  starvation  the  urine  may 
become  richer  in  potassium  than  in  sodium,  which  resujts  from  the 
lack  of  common  salt  and  the  destruction  of  tissue  rich  in  potassium. 
The  quantity  of  potassium  may  be  relatively  increased  during  fever, 
wliile  after  the  crisis  the  reverse  is  the  case. 

The  quantitative  estimation  of  these  bodies  is  performed  by  the 
gravimetric  methods  as  described  in  works  on  quantitative  analysis. 

Ammonia.  Some  ammonia  is  habitually  found  in  human  urine 
and  in  that  of  carnivora.  This  ammonia  may  represent,  as  above 
stated  (page  455),  on  the  formation  of  urea  from  ammonia,  the 
small  amount  of  ammonia  which,  because  of  the  excess  of  acids 
formed  by  the  combustion,  as  compared  with  the  fixed  alkalies,  is 
united  with  such  acids,  and  in  this  way  is  excluded  from  the  synthesis 
to  urea.  This  view  is  confirmed  by  the  observations  of  Coranda,' 
who  found  that  the  elimination  of  ammonia  was  smaller  on  a  vege- 
table diet  and  larger  on  a  rich  meat  diet  than  when  on  a  mixed  diet. 
On  a  mixed  diet  the  average  amount  of  ammonia  eliminated  by  the 
nrine  is  about  0.7  grm.  NH^  per  twenty-four  hours  (Xeubauer'). 
All  the  ammonia  of  the  urine,  as  above  stated,  is  not  represented  by 
the  residue  which  has  eluded  synthesis  into  urea  by  neutralization 
by  acids  because,  as  shown  by  Stadelmanx  and  Beci^mann,* 
ammonia  is  eliminated  by  the  urine  even  during  the  continuous 
administration  of  fixed  alkalies. 

The  experiments  of  many  investigators'  have  shown  that  in  man 
and  carnivora  no  formation  of  urea  takes  place  from  ammonia  salts 
with  mineral  acids  such  as  ammonium  chloride,  but  they  are  elimi- 
nated as  such  in  the  urine,  while,  on  the  contrary,  in  herbivora  a 
formation  of  urea  may  take  place  from  ammonium  chloride.  In 
herbivora  the  HCl  of  the  ammonium  chloride  combines  with  fixed 
alkalies,  and  the  ammonia  set  free  is  available  for  the  formation  of 

'  Vircliow's  Arcli,,  Bd.  53. 
5  Arch.  f.  exp.  Patli.  u.  Pharm.,  Bd.  12. 
^  Huppert  Neubauer,  Harnanalyse,  10.  Aufl.,  S.  42. 

*  Stadeliuann,  Einfluss  der  Alkaliea  auf  den  Stoffwechsel  des  MenscLen. 
Stuttgart,  1890,  S.  52. 

•''  See  footnotes  page  4S»5. 


518  THE   ORINE. 

nrea.  This  difference  in  the  behavior  of  ammonium  chloride  in 
carnivora  and  herbivora  is  dependent  upon  the  different  behavior  of 
the  acids  in  the  organism  of  these  two  groups  of  animals.  The 
quantity  of  ammonia  in  human  and  carnivoral  urine  is  in- 
creased by  the  introduction  of  mineral  acids,  and,  as  shown  by 
JoLiN,'  organic  acids,  like  benzoic  acid,  which  is  not  burned  in  the 
body,  act  in  a  similar  way.  This  depends  upon  the  fact  that  the 
organism  of  these  animals  has  the  property  of  producing  sufficient 
ammonia  by  destruction  of  proteids  to  neutralize  the  acids  intro- 
duced and  in  this  way  prevent  a  destructive  abstraction  of  fixed 
alkalies.  Herbivora,  on  the  contrary,  lack  this  property.  In  them 
the  acids  introduced  are  neutralized  by  fixed  alkalies  ;  hence  the 
introduction  of  mineral  acids  soon  causes  a  destructive  action  on 
account  of  the  abstraction  of  alkalies. 

Acids  formed  in  the  destruction  of  proteids  in  the  body  act  like 
those  introduced  from  without  on  the  elimination  of  ammonia. 
For  this  reason  the  quantity  of  ammonia  in  human  and  carnivoral 
urine  is  increased  under  such  conditions  and  in  such  diseases 
where  an  increased  formation  of  acid  takes  place  due  to  an 
increased  metabolism  of  proteids.  This  is  the  case  in  fevers  and 
diabetes.  In  the  last-mentioned  disease  an  organic  acid,  /?-oxy- 
butyric  acid,  is  produced,  which  passes  into  the  urine  combined 
with  ammonia.  As  the  elimination- of  ammonia  and  the  formation 
of  urea  stand  in  close  relation  to  each  other,  it  was  expected  that  an 
increase  in  the  elimination  of  ammonia  and  a  decrease  in  the  forma- 
tion of  urea  would  take  place  in  certain  diseases  of  the  liver.  We 
have  given  above,  on  the  formation  of  urea  in  the  liver,  the  extent 
of  agreement  of  this  statement,  and  the  reader  is  referred  to  the 
works  there  cited. 

The  detection  and  quantitative  estimation  of  ammonia  is  per- 
formed generally  according  to  the  method  suggested  by  Schlosing. 
The  principle  of  this  method  is  that  the  ammonia  from  a  measured 
amount  of  urine  is  set  free  by  lime-water  in  a  closed  vessel  and 

absorbed  by  a  measured  amount  of  —  sulphuric  acid.     After  the 

absorption  of  the  ammonia  the  quantity  is  determined  by  titrating 

the  remaining  free  sulphuric  acid  with  a  —  caustic  alkali.     This 

method  gives  low  results,  and  in  exact  work  we  must  proceed  as 

1  Skand.  Arch.  f.  Physiol.,  Bd.  1. 


QUANTITY  AND   qUANTTTATIVE  GOMPOSITION.         ."iiy 

suggested  by  Bohland,'  Other  methods  have  been  suggested  by 
SCHMIEDEBEKG  '  and  by  Latschenberuer.' 

Calcium  and  magnesium  occur  iu  the  urine  for  the  most  part  as 
phosphates.  The  quantity  of  earthy  phosphates  eliminated  daily 
is  somewhat  more  than  1  gr.,  and  of  this  amount  f  is  magnesium 
and  ^  calcium  phosphate.  In  acid  urines  the  simple-  as  well  as  the 
double-acid  earthy  pliosphates  are  found,  and  the  solubility  of  the 
first,  among  which  the  calcium-salt,  CaHPO,,  is  especially  insolu- 
ble, is  particularly  augmented  by  the  presence  of  double-acid  alkali 
phosphate  and  sodium  chloride  in  the  urine  (Ott'').  The  quantity 
of  alkaline  earths  in  the  urine  depends  on  the  composition  of  the 
food.  Nothing  is  known  with  positiveness  in  regard  to  the  constant 
and  regular  change  in  the  elimination  of  these  substances  in  disease. 

The  quantity  of  calcium  and  magnesium  is  determined  accord- 
ing to  the  ordinary  well-known  methods. 

Iron  occurs  in  the  urine  only  in  small  quantities,  and,  as  it  seems  from  the 
investigations  of  Kunkel,^  Uiacosa,*  Kt)BERT,''  and  his  pupils,  it  does  not 
exist  as  a  salt,  but  as  an  organic  combination — in  part  aa  pigment  orchromogen. 
The  statements  in  regard  to  tlje  quantity  of  iron  seem  to  show  that  the  quantity 
is  very  varialjle,  from  1  to  11  milligrammes  per  litre  of  urine  (Magnier,* 
Gottlieb,'*  Kobert,  and  his  pupils).  The  quantity  of  silicic  acid,  according 
to  tlie  ordinary  statements,  amounts  to  about  0.03  p.  m.  Traces  of  hydrogen 
peroxide  also  occur  in  the  urine. 

The  gases  of  the  urine  are  carbon  dioxide,  nitrogen,  and  traces 
of  oxygen.  The  quantity  of  nitrogen  is  not  quite  1  vol.  per  cent. 
The  carbon  dioxide  varies  considerably.  In  acid  urines  it  is  hardly 
one  half  as  great  as  in  neutral  or  alkaline  urines. 

IV.   The  Quantity  and  Quantitative  Composition 

of  Urine. 

A  direct  participation  of  the  kidney  substance  in  the  formation 
of  the  urinary  constituents  is  proved  at  least  for  one  constituent  of 
the  urine,  namely,  hippuric  acid.     It  is  hardly  to  be  doubted  that 

'  Pflilger'sArch.,  Bd.  43 

'  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  7. 

*  Monatshefte  f .  Chem. ,  Bd.  5. 
♦Zeitschr.  f.  physiol.  Chem.,  Bd.  10. 

*  Sitzungsber.  d.  phys.-med.  Gesellsch.  zu  Wiirzburg,  1881.  Cited  from 
Maly's  Jahresber.,  Bd.  11,  S.  346. 

6  See  Maly's  Jahresber.,  Bd.  16,  S.  213. 

'  Arbeiten  des  pharm.  Instit.  zu  Dorpat,  Bd.  7.     Stuttgart,  1891. 

*  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  7. 
9  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  26. 


520  THE   URINE. 

the  kidneys  as  well  as  the  tissues  generally  have  a  certain  part  to 
play  in  the  formation  of  other  urinary  constituents,  but  their  chief 
task  consists  in  separating  and  removing  urinary  constituents  dis- 
solved in  the  blood  which  have  been  taken  up  by  it  from  other 
organs  and  tissues. 

It  has  been  shown  by  the  experiments  of  numerous  investigators, 
Heidenhain,  v.  Wittich,  Nfssbaum,  Neisser,  Ustimowitsch, 
I.  MuNK,  and  others,  that  the  elimination  of  water  and  the  remain- 
ing urinary  constituents  is  not  alone  produced  by  simple  diffusion 
and  filtration/  It  is  generally  conceded  that  the  processes  of 
urinary  secretion  depend  essentially  upon  a  sj)ecific  activity  of  the 
cells  of  the  epithelium  of  the  urinary  passages,  besides  which  also 
processes  of  filtration  and  diffusion  take  part.  The  process  of  the 
secretion  of  urine  in  man  and  the  higher  animals  is  generally  con- 
sidered to  proceed  chiefly  as  follows:  The  water  together  with  a 
small  amount  of  the  salts  passes  through  the  glomeruli,  while  the 
chief  part  of  the  solids  is  secreted  by  the  epithelium  of  the  urinary 
passages.  A  secretion  of  solids  without  a  simultaneous  secretion 
of  water  is  not  possible,  and  therefore  a  part  of  the  water  must  be 
secreted  by  the  epithelium-cells  of  the  urinary  passages.  The 
passage  of  the  chief  part  of  the  water  through  the  glomeruli  is 
rather  generally  considered  as  a  filtration  due  to  blood-pressure. 
According  to  Heidenhaiit,  the  thin  cell-layers  of  the  glomeruli 
have  a  secretory  action. 

The  quantity  and  the  composition  of  urine  are  liable  to  great 
variation.  Those  circumstances  which  under  physiological  condi- 
tions exercise  a  great  influence  are  the  following:  the  blood-pressure, 
and  the  rapidity  of  the  blood-current  in  the  glomeruli ;  the  quantity 
of  urinary  constituents,  especially  water  in  the  blood;  and  lastly, 
the  condition  of  the  secretory  glandular  elements.  Above  all,  the 
quantity  and  concentration  of  the  urine  depend  on  the  elimination 
of  water.  That  this  last  may  vary  with  the  quantity  of  water  in  the 
blood,  with  changed  blood -press  are,  and  with  circulatory  conditions 
is  evident;  but  under  ordinary  circumstances  the  quantity  of  water 
eliminated  by  the  kidneys  depends  essentially  upon  the  quantity  of 
water  which  is  brought  to  them  by  the  blood  or  which  leaves  the 
body  by  other  exits.  The  elimination  of  urine  is  increased  by 
drinking    freely,   or   by  reducing  the  quantity  of  water  removed 

'  See  Heidenhain,  Die  Harnabsonderung  in  Hermann's  Handbuch,  Bd.  5, 
Thl.  1,  S.  379. 


QUANTITY.  521 

in  other  ways;  but  it  is  decreased  by  a  diminished  introduction 
of  water,  or  by  a  greater  loss  of  water  in  other  ways.  Ordinarily  in 
man  jast  as  much  water  is  eliminated  by  the  kidneys  as  by  the  skin, 
lungs,  and  intestine  together.  At  lower  temperatures  and  in  moist 
air,  since  under  these  conditions  the  elimination  of  water  by  the 
skin  is  diminished,  the  elimination  of  urine  may  be  considerably 
increased.  Diminished  introduction  of  water  or  increased  elimina- 
tion of  water  by  other  means — as  in  violent  diarrhcea,  violent  vomit- 
ing, or  abundant  perspiration — greatly  diminishes  the  elimination 
of  urine.  For  example,  the  urine  may  sink  as  low  as  500-400  c.  c. 
per  day  in  intense  summer-heat,  while  after  copious  draughts  of 
water  the  elimination  of  3000  c.  c.  of  urine  has  been  observed 
during  the  same  time.  The  average  quantity  of  urine  voided  in 
the  course  of  "24  hours  must  undergo  considerable  variation ;  ordi- 
narily it  is  calculated  as  1500  c.  c.  for  healthy  adult  men  and  1200 
c.  c.  for  women.  The  minimum  elimination  occurs  during  the 
night,  between  2  and  4  o'clock;  the  maximum,  in  the  first  hours 
after  awaking  and  from  1-2  hours  after  a  meal. 

The  qnantity  of  solids  excreted  in  the  course  of  24  hours  is 
rather  constant  even  though  the  quantity  of  urine  may  vary,  and  it 
is  more  constant  when  the  manner  of  living  is  regular.  Therefore 
the  percentage  of  solids  in  the  urine  is  naturally  in  an  inverse  pro- 
portion to  the  quantity  of  urine.  The  average  quantity  of  solids 
per  24  hours  is  calculated  as  60  grms.  The  quantity  may  be  cal- 
culated with  approximate  accuracy  by  means  of  the  specific  gravity 
if  the  second  and  third  decimals  of  the  specific  gravity  be  multiplied 
by  Hasek's  coefficient,  2.33.  The  product  gives  the  amount  of 
solids  in  1000  c.  c.  of  urine,  and  if  the  quantity  of  urine  eliminated 
in  the  24  hours  be  measured,  the  quantity  of  solids  in  the  24  hours 
may  be  easily  calculated.  For  example,  1050  c.  c.  of  urine  of  a 
specific  gravity  1.021  was  eliminated  in  the  24  hours;  therefore  the 

48  9  X  1050 
quantity  of  solids  eliminated  is  21  x  2.33  =  48.9,  and  — -'         

=  51.35  grms.  The  urine  in  this  case  contained  48.9  p.  m.  solids 
and  51.35  grms.  in  the  daily  excretion. 

Those  bodies  which,  under  physiological  conditions,  affect  the 
density  of  the  urine  are  common  salt  and  urea.  The  specific 
gravity  of  the  first  i„  2.15  and  the  last  only  1.32,  so  it  is  easy  to 
understand,  when  the  relative  proportion  of  these  two  bodies  essen- 
tially deviates  from  the  normal,  why  the  above  calculation  from  the 


522  THE   URINE. 

specific  gravity  is  not  exact.  The  same  is  the  case  when  a  nrine 
poor  in  a  normal  constituent  contains  large  amounts  of  foreign 
bodies,  such  as  albumin  or  sugar. 

As  above  stated,  the  percentage  of  solids  in  the  urine  generally 
decreases  with  a  greater  elimination,  and  a  very  considerable  excre- 
tion of  urine  {polyuria)  has  therefore,  as  a  rule,  a  lower  specific 
gravity.  An  important  exception  to  this  rule  is  observed  in  urine 
containing  sugar  {diabetes  meUitus),  in  which  there  is  a  copious 
excretion  of  a  very  high  specific  gravity  due  to  the  sugar.  In  cases 
where  very  little  urine  is  secreted  {oliguria),  as  when  the  perspira- 
tion is  profuse,  in  diarrhoea,  and  in  fevers,  the  specific  gravity  of 
the  urine  is  as  a  rule  high,  the  percentage  of  solids  high,  and  has 
a  dark  color.  Sometimes,  as,  for  example,  in  certain  cases  of 
albuminuria,  the  urine  may  have  a  low  specific  gravity,  notwith- 
standing the  oliguria,  and  be  poor  in  solids  with  a  light  color. 

It  is  difficult  to  give  a  tabular  view  of  the  composition  of  urine, 
on  account  of  its  variation.  For  certain  purposes  the  following 
table  may  be  of  some  value,  but  it  must  not  be  overlooked  that  the 
results  are  not  given  for  1000  parts  of  nrine,  but  only  approximate 
figures  for  the  quantities  of  the  most  important  constituents  which 
are  eliminated  in  the  course  of  24  hours  in  a  quantity  of  1500  c.  c. 

Daily  quantity  of  solids  =  60  grins. 


Organic  constituents  =  35  grnis. 

Urea SO.Ogrms. 

Uric  acid 0.7     " 

Creatinin 1.0     " 

Hippuric  acid 0.7     " 

Remaining  organic  bodies  2.6     " 


Inorganic  constituents  =  25  grms. 
Sodium  chloride  (NaCl)  15  0  grms. 
Sulphuric  acid  (H2SO4).     2.5      " 
Phosphoric  acid  (P2O6).     2.5      " 

Potash  (K2O) 3.3      " 

Ammonia  (NH3)   0.7      " 

Magnesia  (MgO) 0.5      " 

Lime  (CaO) 0.3      " 

Remaining  inorg.  bodies    0.2      " 

Urine  contains  on  an  average  40  p.  m.  solids.  The  quantity  of 
nrea  is  about  20  p.  m.  and  common  salt  about  10  p.  m. 

V.  Casual  Urinary  Constituents. 

The  casual  appearance  in  the  urine  of  medicines  or  of  urinary 
constituents  resulting  from  the  introduction  of  foreign  substances 
into  the  organism  is  of  practical  importance,  because  such  constitu- 
ents may  interfere  in  certain  urinary  investigations,  and  also  because 
they  afford  a  good  means  of  determining  whether  certain  substances 
have  beeii  introduced  into  the  organism  or  not.  From  this  point  of 
view  a  few  of  these  bodies  will  be  spoken  of  in  a  following  section 


CASUAL   CONSTITUENTS.  523 

(on  the  pathological  urinary  constituents).  The  presence  of  these 
foreign  bodies  in  the  urine  is  of  special  interest  in  those  cases  in 
which  they  serve  to  elucidate  tlie  chemical  transformations  certain 
substances  undergo  within  the  body.  As  inorganic  substances 
generally  leave  the  body  unchanged,  they  are  of  very  little  interest 
from  this  standpoint,  but  the  changes  which  certain  organic  sub- 
stances undergo  when  introduced  into  the  animal  body  may  be 
studied  by  this  means  so  far  as  these  transformations  are  sliown  by 
the  urine. 

The  bodies  belonging  to  the  fatty  series,  though  not  without 
exceptions,  fall  mostly  into  a  combustion  leading  towards  the  final 
products  of  metabolism;  still,  often  a  smaller  or  greater  part  of  the 
body  in  question  eludes  oxidation  and  appears  unchanged  in  the 
urine.  A  part  of  the  organic  acids,  which  are  otherwise  bnrnt  into 
water  and  carbonates  and  render  the  urine  neutral  or  alkaline,  may 
act  in  this  manner.  The  volcdile  fatty  acids  poor  in  carbon  are  less 
easily  burnt  than  those  rich  in  carbon,  and  they  therefore  pass  un- 
changed into  the  urine  in  large  amounts.  This  is  especially  true  of 
formic  and  acetic  acids  (Schottex,"  Grehaxt  and  Quinquaud'). 
According  to  Gaglio  oxalic  acid  is  not  oxidized  in  the  animal  body, 
while  Makfori  ^  claims  that  it  is  nearly  entirely  consumed. 

The  acid  amides  appear  not  to  be  changed  in  the  body 
(ScHULTZEX  and  Nencki  ').  A  small  part  of  the  amido-acids  seems 
indeed  to  be  eliminated  unchanged,  but  otherwise  they  are,  as  stated 
above  (page  455)  for  leucin,  glycocoU,  and  aspartic  acid,  decomposed 
within  the  body,  and  they  may  therefore  cause  an  increased  elimi- 
nation of  urea.  Sarcosin  (methylglycocoll),  XH(CH3).CH,.C00H, 
also  perhaps  passes  in  small  part  into  the  corresponding  urami- 
do-acid,  metlujlliydantoinic  acid,  iS'H,.C0.X(CHJ.CH2.C00H 
(ScHULTZEN  ^).  Also  tauriu,  amido-ethylsul phonic  acid,  which 
acts  somewhat  differently  in  different  animals  (Salkowski'),  passes 
in  human  beings,  at  least  in  part,  into  the  corresponding  uramido- 
acid,  taurocarlamic  acid,  NH^.CO.JSTH.CjH^.SOj.OH.     A  part  of 

1  Zeitschr.  f.  pliysiol.  Chem.,  Bd.7,  S.  375. 

'  Compt.  rend.,  Tome  104. 

3  See  Maly's  Jaliresber.,  Bd.  16,  S.  403,  and  Bd.  20,  S.  70. 

*  Zeitschr.  f.  Biologie,  Bd.  8. 

'  Ber.  d.  deutsch.  cliem.  Gesellsch.,  Bd.  5.  See  also  Baumann  and  v. 
Mering,  ihid.,  Bd.  8,  S.  584,  and  E.  Salkowski,  Zeitschr.  f.  pbysiol.  Chem.,  Bd. 
4,  S.  107. 

'  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  6,  and  Vircbow's  Arch..  Bd.  58. 


524  TEE   URINE. 

the  taurin  appears  as  such  in  the  nrine.  In  rabbits,  when  tanrin 
is  introduced  into  the  stomach,  nearly  all  its  sulphur  appears  in  the 
nrine  as  sulphuric  and  liyposulphurous  acids.  After  subcutaneous 
injection  the  taurin  appears  again  in  great  part  unchanged  in  the 
urine. 

A  conjugation  of  bodies  of  the  fatty  series  with  glycocoll  may 
also  occur.  As  shown  by  Jaffe  and  Qo'B.is,^  furfurol,  which  is  the 
aldehyde  of  pyromucic  acid,  when  introduced  into  rabbits  and  dogs 
is  first  oxidized  into  pyromucic  acid  and  then  this  eliminated  as 
pyromucuric  acid,  C,H,N^O,  after  conjugation  with  glycocoll.  In 
birds  this  behavior  is  different,  namely,  in  them  the  acid  is  con- 
jugated to  another  substance,  ornitliin.,  C^Hj^N^O^,  which  is  probably 
diami  do  valerianic  acid,  forming  pyromucinorthuric  acid.'^  Like 
fnrfurol  so  is  tMophen,  O^H^S,  corresponding  to  furfuran,  oxidized 
to  tliiophenic  acid,  which,  according  to  Jaffe  and  Levt,^  is  con- 
jugated with  glycocoll  in  the  body  (rabbits)  and  eliminated  as 
thiophenuric  acid,  C^H^NSOj. 

Furfurol  also  undergoes  conjugation  with  glycocoll  "in  other 
forms  in  mammals.  Thus  Jaffe  and  Cohk  found  that  it  in 
part  combined  with  acetic  acid,  forming  furfiiracrylic  acid, 
C^HgO.CHiCH.COOH,  which  passes  into  the  urine  coupled  with 
glycocoll  Q&  fiirfuracryluric  acid. 

Conjugation  with  glycuronic  acid  occurs  in  certain  substituted 
alcohols,  aldehydes,  and  ketones  (?),  which  probably  first  pass  over 
into  alcohols  (Sujstdvik').  Chloral  hydrate,  C^ClgOH  +  H^O, 
passes,  after  it  has  been  converted  into  trichlorethyl-alcohol  by  a 
reduction,  into  a  Igevogyrate  reducing  acid,  urochloralic  acid  or 
trichlorethyl-glycuronic  acid,  C^CljIi^.C^H^O,  (MuscuLUS  and 
V.  Meriistg^).  Trichlorhutyl-alcohol  and  butyl-chloral  hydrate  also 
pass  into  trichlorMityl-glycuronic  acid.  In  animals  which  have 
starved  until  the  glycogen  has  disappeared  from  the  muscles  and 
liver  and  which  are  given  chloral  hydrate  or  dimethyl  carbinol, 
conjugated  glycuronic  acids  appear  in  the  urine  (Thierfelder '). 
On  account  of  these  facts  the  albuminous  bodies  are  considered  the 

•  Ber.  d.  deutsch.  cliem.  Gesellsch.,  Bd.  20. 
»  Jaffe  and  R.  Cohn,  ibid.,  Bd.  21,  S.  3461. 

3  ii^icl.,  Bd.  21,  S.  3458. 

*  See  Maly's  JaLresber.,  Bd.  16,  S.  76. 

''Ber.  d.   deutsch.   chem.  Gesellsch.,   Bd.   8;  also  v.  Mering,   Zeitschr.    f. 
physiol.  Cbern.,  Bd,  6,  and  E.  Kiilz,  Pfliiger's  Arch,,  Bd.  28. 
«  Zeitschr.  f.  physiol.  Chem.,  Bd.  10. 


CASUAL   CONSTITUENTS.  525 

origin  of  the  glycaronic  acid.  It  may  perhaps  originate  from  snch 
proteids,  which  are  found  widely  diffused  in  the  body,  and  from 
which  carbohydrates  or  near-related  acids  may  be  split.  The  above 
starvation  experiments  are  perhaps  not  quite  free  from  exceptions.' 

The  aromatic  combinations  pass,  as  far  as  we  know,  into  the 
urine  as  such  generally  after  a  previous  partial  oxidation  or  after  a 
synthesis  with  other  bodies.  That  the  benzol  ring  is  destroyed  in 
the  body  in  certain  cases  is  very  probable. 

The  fact  that  benzol  may  be  oxidized  outside  of  the  body  into 
carbon  dioxide,  oxalic  acid,  and  volatile  fatty  acids  has  been  known 
for  a  long  time,  and  we  may  refer  the  reader  to  the  investigations 
of  Drechsel,  mentioned  in  the  first  chapter,  in  which  this  experi- 
menter obtained,  by  the  electrolysis  of  phenol,  normal  caproic  acid 
and  afterward  substances  in  which  the  quantity  of  carbon  decreased 
constantly  until  he  obtained  the  final  products  of  metabolism.  As 
in  these  experiments  a  splitting  of  the  benzol  ring  must  take  place 
before  the  formation  of  the  bodies  of  the  fatty  series,  also  when 
aromatic  bodies  are  consumed  in  the  animal  body,  we  must  admit 
that  first  a  rupture  of  the  benzol  ring  takes  place  with  the  forma- 
tion of  fatty  bodies.  If  this  does  not  take  place,  then  the  benzol 
nucleus  is  eliminated  with  the  urine  as  an  aromatic  combination  of 
one  kind  or  another.  As  the  difficultly  destroyed  benzol  nucleus 
can  protect  from  destruction  a  substance  belonging  to  the  fatty 
series  when  conjugated  with  it,  which  is  the  case  with  the  glyoocoll 
of  hippuric  acid,  it  seems  also  that  the  aromatic  nucleus  itself  may 
be  protected  from  destruction  in  the  organism  by  syntheses  with 
other  bodies.  The  aromatic  ethereal-sulphuric  acids  are  examples 
of  this  kind. 

The  difficulty  in  deciding  whether  the  benzol  ring  itself  is 
destroyed  in  the  body  lies  in  the  fact  that  we  do  not  know  all  the 
different  aromatic  transformation  products  which  may  be  produced 
by  the  introduction  of  any  aromatic  substance  in  the  organism  and 
which  we  must  seek  for  in  the  urine.  On  this  account  it  is  also 
impossible  to  learn  by  exact  quantitative  estimations  whether  or  not 
an  aromatic  substance  introduced  or  absorbed  appears  again  in  its 
entirety  in  the  urine.  Certain  observations  render  it  probable  that 
the  benzol  ring,  as  above  mentioned,  is  at  least  in  certain  cases 
destroyed  in  the  body.     Schotten  '  and  Baumann  '  have  found 

1  See  Nebeltliau,  Zeitscbr.  f.  Biologie,  Bd.  28,  S.  130. 

2  Zeitsclir.  f.  physiol.  Chem.,  Bdd.  7  and  8. 

'^  Ibid.,  Bd.   10,  S.  130,     In  regard  to  tyrosin  see  especially  Blendermann, 


526  THE    URINE. 

that  certain  ami  do-acids,  sach  as  tyrosin,  phenylamido-propionic 
acid,  and  amido-cinnamic  acid  when  introduced  into  the  body  cause 
no  increase  in  the  quantity  of  known  aromatic  substances  in  the 
urine;  thfs  makes  a  destruction  of  these  amido-acids  in  the  animal 
body  seem  probable.  Juyalta  '  also  made  an  experiment  on  dogs 
with  plithalic  acid,  and  found  that  57.5-68.76^  of  the  acid  intro- 
duced into  the  body  disappeared,  or  more  correctly  was  not  found 
again.  According  to  Juvalta,  this  acid  does  not  undergo  any 
synthesis,  nor  does  it  yield  any  aromatic  transformation  products; 
and  if  this  supposition  be  correct,  we  have  here  a  proof  of  the 
destruction  of  the  benzol  nucleus  of  a  part  of  the  phthalic  acid 
introduced  into  the  organism  of  the  dog. 

An  oxidation  in  the  side  chain  of  aromatic  compounds  is  often 
found,  and  may  also  occur  in  the  nucleus  itself.  As  an  example, 
benzol  is  first  oxidized  to  oxybenzol  (Schultzen  and  I^auxtn'), 
and  this  is  then  in  part  converted  into  dioxyhenzols  (Baumanjst  and 
Pkeusse^).  NapMlialin  appears  to  be  converted  into  oxynaph- 
tJialin,  and  probably  a  part  also  into  dioxynapTitlialin  (Lesiv"ie:  and 
M.  Neitcki').  Anilin,  C^H^.NH^,  passes  into  paramidophenol,' 
which  passes  into  the  urine  as  ethereal-sulphuric  acid,  H^N.CJI^. 
O.SO,.OH  (F.  Muller'). 

If  the  aromatic  substance  has  a  side  chain  belonging  to  the 
fatty  series,  this  last  is  generally  oxidized.  For  example,  toluol, 
CgH^.CH,  (ScHULTZEN  and  Naun-yx '),  etliyl-lenzol,  C^H^.C^H,, 
and  propylbeiizol,  CJl^.GJl^  (Nexcki  and  Giacosa'),  also  many 
other  bodies  are  oxidized  into  benzoic  acid.  If  the  side  chain  has 
several  members,  the  behavior  is  somewhat  different.  Phenyl-acefic 
acid,  C,H,.CH2.C00H,  in  which  only  one  carbon  atom  exists 
between  the  benzol  nucleus  and  the  carboxyl,  is  not  oxidized,  but 

Zeitschr.  f.  physiol.  Cliem.,  Bd.  6;  Scliotten,  iUd.,  Bd.  7;  Baas,  ibid.,  Bd.  11; 
and  R.  Colin,  ibid.,  Bd.  14. 

'  Zeitsclir,  f.  physiol.  Chem.,  Bd.  13. 

2  Reiclierf s  und  Da  Bois-Reymonds  Arch.,  1867. 

'  Zeilschr.  f.  physiol.  Chem.,  Bd.  3,  S.  156.  See  also  Nencki  and  Giacosa, 
ibid.,  Bd.  4,  S.  336. 

*  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  24.  See  also  Edlefsen,  Maly's  Jalires- 
ber.,  Bd.  18,  S.  116. 

6  Sclimiedeberg,  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  8. 

e  Deutsch.  med.  Wochenschr. ,  1887.  Cited  from  Maly's  Jahresber.,  Bd.  17, 
S.  87. 

■>  Reichert's  and  Du  Bois-Reymond's  Arch.,  1867. 

8  Zeitschr.  f.  physiol.  Chem.,  Bd.  4. 


CASUAL   CONSTITUENTS.  527 

is  eliminated  after  conjugation  with  glycocoll  as  j'j/iewace^Mrtc  acid 
(Salkowski ').  Phenyl-propionic  acid,  CJI^.CH,.CII^.COOH, 
with  two  carbon  atoms  between  the  benzol  nucleus  and  the  carboxjl 
is,  on  the  contrar}^  oxidized  into  benzoic  acid."  Aromatic  amido- 
acids  with  three  carbon  atoms  in  the  side  chain,  and  where  the  NH, 
group  is  bound  to  the  middle  one,  as  in  tyrosifi,  o'-oxyphenylamiLlo- 
propionic  acid,  C,H,(OH).CH,.CH(NHJ.COOH,  and  a-phenyl- 
ainido-propionic  acid,  CJI^.CH,.CH(NHJ.COOH,  seem  to  be  in 
great  part  burnt  within  the  body.  Plienylamido-acetic  acid,  which 
has  only  two  carbon  atoms  in  the  side  chain,  OjH^.CII(NHJ.COOH, 
acts  otherwise,  passing  into  mandelic  acid,  phenyl-glycolic  acid, 
C.H,.CH(OH).COOH  (ScHOTTEN^'). 

If  several  side  chains  are  present  in  the  benzol  nucleus,  then 
only  one  is  always  oxidized  into  carboxyl.  Thus  xylol,  CJI^(CH3)j, 
is  oxidized  into  toluic  acid,  CJI^(CH3)C00H  (Schultzen"  and 
Naunyn*),  mesiUjUn,  C^H3(CH3)„  into  mesitylcnic  acid, 
CgH,(CH,),.COOH  (L.  Nencki'),  and  cy^nol  into  cumic  acid 
(M.  Nencki  and  Ziegler"). 

Syntheses  of  aromatic  substances  with  other  atomic  groups  occur 
frequently.  To  these  syntheses  belongs,  in  the  first  rank,  the 
conjugation  of  benzoic  acid  with  glycocoU  to  form  hippuric  acid, 
first  discovered  by  Wohler.  All  the  numerous  aromatic  substances 
which  are  converted  into  benzoic  acid  in  the  body  are  voided  partly 
as  hippuric  acid.  This  statement  is  not  true  for  all  classes  of 
animals.  According  to  the  obser\rations  of  Jaffe,'  benzoic  acid 
does  not  pass  into  hippuric  acid  in  birds,  but  into  another  nitro- 
genous acid,  ornithuric  acid,  0,^11, „N^0^.  This  acid  yields  as 
splitting  products,  besides  benzoic  acid,  a  body,  ornitliin,  which 
has  been  spoken  of  on  page  524.  Not  only  are  the  oxybenzoic  acids 
and  the  substituted  benzoic  acids  (Bertagnini  *)  conjugated  with 
glycocoll,  forming  corresponding  hippuric  acids,  but  also  the  above- 
mentioned  acids,  toluic,  mesitylenic,  cumic,  and  plienylacetic  acids. 

*  Zeitschr.  f.  physiol.  Chein.,  Bdd.  7  and  9. 

'  See  E.  and  H.  Salkowski,  Ber.  d.  deutsch.  chem.  Gesellscli.,  Bd.  13. 

3  Zeitschr.  f.  physiol.  Chein.,  Bd.  8. 

^  Reichert's  und  Du  Bois-Reymond's  Arch.,  1867. 

5  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  ]. 

«  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  5;  see  also  0.  Jacobsen,  ibid.,  Bd. 


12. 


""  Ibid.,  Bdd.  10  and  11. 

•  Cited  from  Kiihne's  Lehrbuch,  S.  91. 


528  THE    URINE. 

These  acids  are  voided  as  toluric,  mesitylenuric,  cuminuric,  and 
phenaceturic  acids. 

It  must  be  remarked  in  regard  to  the  oxybenzoic  acids  that  a 
conjugation  with  glycocoll  has  only  been  positively  proven  with  sali- 
cylic acid  and  p-oxybenzoic  acid  (BERTAG]srii?'i,  Baumann  and 
Herter,'  and  others),  while  Baumann  and  Herter  find  it  only 
very  probable  for  m-oxybenzoic  acid.  The  oxybenzoic  acids  are  also 
in  part  eliminated  as  conjugated  sulphuric  acids,  which  is  especially 
true  for  m-oxybenzoic  acid."  We  have  the  investigations  on 
m-amidobenzoic  acid  in  regard  to  the  transformation  of  amido- 
benzoic  acids.  Salkowski  '  found,  as  was  later  confirmed  by 
R.  CoHN,*  that  m-amidobenzoic  acid  passes  in  part  into  uramido- 
lenzoic  acid,  H^JSr.CO.HN.C^H^.COOH.  It  is  also  in  part  elimi- 
nated as  amidohippuric  acid. 

The  substituted  aldehydes  are  of  special  interest  as  substances 
which  undergo  conjugation  with  glycocoll.  According  to  the  inves- 
tigations of  R.  CoHN  ^  on  this  subject  o-nitrobenzaldehyde  when 
introduced  into  a  rabbit  is  only  in  a  very  small  part  converted  into 
nitrobenzoic  acid,  and  the  chief  mass,  about  90^,  is  destroyed  in  the 
body.  According  to  Sieber  and  Smirnow  "  m-nitrobenzaldehyde 
passes  in  dogs  into  m-nitrohippuric  acid,  and  according  to  Cohn" 
into  urea  m-nitrohippurate.  In  rabbits  the  behavior  is  quite 
different  according  to  Cohn",  In  this  case  not  only  does  an  oxida- 
tion of  the  aldehyde  into  benzoic  acid  take  j)lace,  but  the  nitro 
group  is  also  reduced  to  an  amido  group,  and  finally  acetic  acid 
attaches  itself  to  the  amido  group  with  the  expulsion  of  water,  so 
tbat  the  final  product,  m-acetylamidobenzoic  acid,  CH3.CO.lSrH. 
CgH^.COOH,  is  the  result.  This  process  is  analogous  to  the  behavior 
of  furfurol,  and  the  reduction  does  not  take  place  in  the  intestine, 
but  in  the  tissue.'  The  p-nitrobenzaldehyde  acts  in  rabbits  in  part 
like  the  m-aldehyde  and  passes  in  part  into  p-acetylamidohenzoic 
acid.  Another  part  is  converted  into  p-nitrobenzoic  acid,  and  the 
urine  contains  a  chemical  combination  of  equal  parts  of  these  two 

'  Zeitschr.  f.  pliysiol.  Chem.,  Bd,  1,  wliich  also  cites  Bertagnini's  work. 
*  See  Baumann  and  Herter,  1.   c. ,  and  also  Dautzenberg  in  Maly's  Jahres- 
ber.,  Bd.  11,  S.  231. 

'  Zeitscbr.  f.  pbysiol.  Cbem.,  Bd.  7. 

"  Ibid.,  Bd.  17,  S.  292. 

^iWfZ.,  Bd.  17. 

6  Mouatsbefte.  f.  Cbem.,  Bd.  8. 

■"  Zeitscbr.  f.  pbysiol.  Cbem.,  Bd.  18. 


CASUAL    CONSTITUENTS.  529 

acids.     According  to  Siebek  and   Smienow  p-nitrobenzaldehyde 
ouly  yields  urea  p-uitroliippurate  in  dogs.' 

Another  very  important  synthesis  of  aromatic  substances  is  that 
of  the  ethereal-sulphuric  acids.  Phenols  and  chiefly  the  hydroxyl- 
ated  aromatic  hydrocarhons  and  their  derivatives  are  voided  as 
ethereal-sulphuric  acids,  according  to  Uaumann,  Herter,  and 
others.* 

A  conjugation  of  aromatic  substances  with  glycuronic  acid, 
which  last  is  protected  from  burning,  occurs  rather  often.  Camphor., 
C,  J-I„0,  when  given  to  a  dog  is  first  converted  by  oxidation  into 
camphoral,  C,„II,j(OH)0,  and  by  conjugation  with  glycuronic  acid 
into  campho-glycuronic  acid  (Schmiedeberg'').  The  phenols,  as 
above  stated  (page  491),  pass  in  part  as  conjugated  glycuronic  acids 
into  the  urine.  The  same  is  true  for  the  homologues  of  phenols, 
for  certain  substituted  phenols,  for  naphthols.,  lorneol.,  menthol., 
turpentine.,  and  many  other  aromatic  substances.''  Orthonitrotoluol 
in  dogs  passes  first  into  o-nitrobenzyl  alcohol  and  then  into  a  con- 
jugated glycuronic  acid,  iironitrotoluoUc  acid  (Jaffe  ").  The  glycu- 
ronic acid  split  off  from  the  conjugated  acid  is  laevogyrate  and 
hence  not  identical  with  the  ordinary  glycuronic  acid,  but  isomeric. 
Indol  and  skatol  seem,  as  above  stated  (page  495  and  496),  to  be 
eliminated  in  the  urine  partly  as  conjugated  glycuronic  acids. 

A  synthesis  in  which  compounds  containing  sulphur,  mercap- 
tu7'ic  acid,  is  formed  and  eliminated  conjugated  with  glj/curonic 
acid,  occurs  when  chlorine  and  bromine  derivates  of  benzol  are  in- 
troduced into  the  organism  of  dogs  (Baumann  and  Preusse," 
Jaffe  ').  Thus  chlorbenzol  combines  with  ctstein,  an  intermediary 
decomposition  product  of  proteids  which  is  closely  allied  to  cystin 
(see  below),  forming  chlorjylienylmercapturic  acid  C,,H,,C1SN03. 
On  boiling  with  mineral  acid  this  compound  decomposes  into  acetic 
acid  and  chlorphenylcystein,  CJI^Cl.CjHj^NSO,. 

'  In  regard  to  the  extensive  literature  on  glycocoll  conjugations  we  refer  the 
reader  to  0.  Kiihling,  Ueber  StofEwechselprodukte  aromatischer  Korper.  In- 
aug.-Diss.     Berlin,  1887. 

2  See  O.  Kiihling,  1.  c. 

*  Schmiedeberg  und  Meyer,  Zeitschr.  f,  physiol.  Chem.,  Bd.  3. 

^  See  0.  Kiihling,  1.  c,  which  gives  the  literature  up  to  1887;  also  E.  Kiilz, 
Zeitschr.  f.  Biologie,  Bd.  27. 

*  Zeitschr.  f.  physiol.  Chem.,  Bd.  2. 
^  Ihid.,  Bd.  5,  S.  309. 

'  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  12. 


530  THE   URINE. 

Pyridin,  C^H^N,  which  does  not  combine  either  with  glyeuronic 
acid  or  with  sulphuric  acid  after  previous  oxidation,  shows  a  special 
behavior.  It  takes  up  a  methyl  group  as  found  by  His  ^  and  later 
confirmed  by  Cohn/  and  forms  an  ammonium  combination, 
methylpyridyl-ammonium  hydroxyl,  HO.CHj.NCj^Hj.  Methylpy- 
ridin  {a-picoUn)  on  the  contrary  passes  in  rabbits  part  in  into 
oc-pyridin  carhonic  acid,  and  is  eliminated  as  a-pyridinuric  acid 
after  conjugation  with  glyeuronic  acid  (E.  Cohn  ').  Several  alka- 
loids, such  as  quinin,  morphin,  and  strychnin,  may  pass  into  the 
urine.  After  taking  turpentine,  'balsam  of  copaiva,  and  resins  these 
may  appear  in  the  urine  as  resin  acids.  Different  kinds  of  coloring 
matters,  such  as  alizarin,  crysophanic  acid,  after  the  use  of  rhubarb 
or  senna,  and  the  coloring  matter  of  the  Uueherry,  etc.,  may  also 
pass  into  the  urine.  After  taking  rhuiarl,  senna,  or  santonin  the 
urine  takes  a  yellow  or  greenish-yellow  color,  which  is  transformed 
into  a  beautiful  red  color  by  the  addition  of  alkali.  Phenol  pro- 
duces, as  above  mentioned,  a  dark -brown  or  dark-green  color  which 
depends  mainly  on  the  decomposition  products  of  hydrochinon  and 
humin  substances.  After  the  use  of  naphthalin  the  urine  has  a 
dark  color,  and  several  other  medicines  produce  a  special  coloration. 
Thus  Tcairin  gives  often  a  yellowish-green  hue,  and  the  urine 
darkens  when  exposed  to  the  air;  thallin  gives  a  greenish-brown 
color  which  is  marked  green  in  thin  layers,  and  antipyrin  gives  a 
yellow  to  blood-red.  After  the  administration  of  lalsam  of  copaiva 
the  urine  becomes,  when  strongly  acidified  with  hydrochloric  acid, 
gradually  rose  and  purple-red  (Quincke').  After  the  use  of 
najMhalin  or  naphthol  the  urine  gives  with  concentrated  sulphuric 
acid  (1  c.  c.  concentrated  acid  and  a  few  drops  of  urine)  a  beautiful 
emerald-green  color  (Peistzoldt'),  which  is  probably  due  to 
naphthol-glycuronic  acid.  Odoriferous  bodies  also  pass  into  the 
urine.  After  eating  asparagus  the  urine  acquires  a  sickly  disagree- 
able odor  which  is  probably  due  to  methylmercaptan,  according  to 
M.  Nencki."  After  taking  turpentine  the  urine  may  have  a 
peculiar  odor  similar  to  that  of  violets. 

1  Arcli.  f.  exp.  Path.  u.  Pbarm.,  Bd.  22. 

2  Zeitscbr.  f.  pbysiol.  Chem.,  Bd.  18,  S.  116. 
2L.  c. 

4  Arch.  1  exp.  Path.  u.  Pbarm.,  Bd.  17. 
^  Ihid.,  Bd.  21. 
«  Ihicl.,  Bd.  28. 


PEOTEID.  531 


VI.  Pathological  Constituents  of  Urine. 

Proteid.  The  appearance  of  slight  traces  of  proteid  in  the  tirine 
of  apparently  healthy  persons  has  been  observed  in  many  cases  by 
several  investigators,  but  still  we  must  not  conceal  the  fact  that 
other  investigators  consider  these  traces  of  proteid  as  the  first 
symptoms,  though  very  mild,  of  a  diseased  condition  of  the  urinary 
apparatus,  or  as  a  symptom  of  a  transitory  disturbance  in  the  circu- 
lation. Frequently  traces  ate  found  in  the  urine  of  a  substance 
similar  to  nucleoalbumin  which  can  easily  be  mistaken  for  mucin 
and  which  is  probably  identical  with  nucleoalbumin.  This  sub- 
stance has  been  isolated  from  the  papillary  part  of  the  kidneys  and 
from  the  mucous  membrane  of  the  bladder  by  Lonnberg.'  In 
diseased  conditions  proteid  occurs  in  the  urine  in  a  variety  of  cases. 
The  albuminous  bodies  which  most  of  ten  occur  are  serglobulin  and 
seralbumin.  Albumoses  and  peptones  also  sometimes  occur.  The 
quantity  of  proteid  in  the  urine  is  in  most  cases  less  than  op.  m., 
rarely  10  p.  m.,  and  only  very  rarely  does  it  amount  to  50  p.  m.  or 
over. 

Among  the  many  reactions  proposed  for  the  detection  of  pro- 
teid in  urine,  the  following  are  to  be  recommended : 

Tlie  Heat  Test.  Filter  the  urine  and  test  its  reaction.  An  acid 
nrine  may,  as  a  rule,  be  boiled  without  further  treatment,  and  only 
in  especially  acid  urines  is  it  necessary  to  first  treat  with  a  little 
alkali.  An  alkaline  urine  is  made  neutral  or  faintly  acid  before 
heating.  If  the  urine  is  poor  in  salts,  add  J^-  vol.  of  a  saturated 
common-salt  solution  before  boiling;  then  heat  to  boiling-point, 
and  if  no  jDrecipitation,  cloudiness,  or  opalescence  appears,  the  urine 
in  qnestion  contains  no  coagulable  proteid,  but  it  niciy  contain 
albumoses  or  peptones.  If  a  precipitate  is  produced  on  boiling,  this 
may  consist  of  proteid,  or  of  earthy  phosphates,  or  of  both.  The 
simple-acid  calcium  phosphate  decomposes  on  boiling,  and  normal 
phosphate  may  separate.  The  proper  amount  of  acid  is  now  added 
to  the  urine,  so  as  to  prevent  any  mistake  caused  by  the  presence  of 
earthy  phosphates,  and  to  give  a  better  and  more  flocculent  precipi- 
tate of  the  proteid.  If  acetic  acid  is  used  for  this,  then  add  1-2-3 
drops  of  a  25,^  acid  to  each  10  c.  c.  of  the  urine,  and  boil  after  the 
addition  of  each  drop.  On  using  nitric  acid,  add  1-2  drops  of  the 
25;^  acid  to  each  c.  c.  of  the  boiling-hot  urine. 

On  using  acetic  acid,  Avhen  the  quantity  of  proteid  is  very  small, 
and  especially  when  the  urine  was  originally  alkaline,  the  proteid 

'  See  page  446. 


533  THE    URINE. 

may  sometimes  remain  in  solution  on  the  addition  of  the  above 
quantity  of  acetic  acid.  If,  on  the  contrary,  less  acid  is  added,  the 
precipitate  of  calcium  phosphate,  which  forms  in  amphoteric  or 
faintly  acid  urines,  is  liable  not  to  dissolve  completely,  and  this 
may  cause  it  to  be  mistaken  for  a  proteid  precipitate.  If  nitric 
acid  is  used  for  the  heat  test,  the  fact  must  not  be  overlooked  that 
after  the  addition  of  only  a  little  acid  a  combination  between  it  and 
the  proteid  is  formed  wliich  is  soluble  on  boiling  and  which  is  only 
precipitated  by  an  excess  of  the  acid.  On  this  account  the  large 
quantity  of  nitric  acid,  as  suggested  above,  must  be  added,  but  in  this 
case  a  small  part  of  the  proteid  is  liable  to  be  dissolved  by  the 
excess  of  the  nitric  acid.  When  the  acid  is  added  after  boiling, 
which  is  absolutely  necessary,  the  liability  of  a  mistake  is  not  so 
great.  It  is  on  these  grounds  that  the  heat  test,  although  it  gives 
very  good  results  in  the  hands  of  experts,  is  not  recommended  to 
physicians  as  a  positive  test  for  proteid. 

A  confounding  with  mucin,  when  this  body  occurs  in  the  urine, 
is  easily  prevented  in  the  heat  test  with  acetic  acid,  by  acidifying 
another  portion  with  acetic  acid  at  the  ordinary  temperature. 
Mucin  and  nncleoalbumin  substances  similar  to  mucin  are  hereby 
precipitated.  If  in  the  performance  of  the  heat  and  nitric  acid 
test  a  precipitate  first  appears  on  cooling  or  is  strikingly  increased, 
then  this  shows  the  presence  of  albumoses  in  the  urine,  either  alone 
or  mixed  with  coagulable  proteid.  In  this  case  a  farther  investi- 
gation is  necessary  (see  below).  In  a  urine  rich  in  urates  a  precipi- 
tate consisting  of  uric  acid  separates  on  cooling.  This  precipitate 
is  colored,  sandy,  and  hardly  to  be  mistaken  for  an  albumose  or 
proteid  precipitate. 

Heller's  test  is  performed  as  follows  (see  page  26) :  The  urine 
is  very  carefully  floated  on  the  surface  of  nitric  acid  in  a  test-tube. 
The  presence  of  proteid  is  shown  by  a  white  ring  between  the  two 
liquids.  With  this  test  a  red  or  reddish-violet  transparent  ring  is 
always  obtained  with  normal  urine;  it  depends  on  the  indigo  color- 
ing matters  and  can  hardly  be  mistaken  for  the  white  or  whitish 
proteid  ring,  and  this  last  must  not  be  mistaken  for  the  ring  pro- 
duced by  bile-pigments.  Tn  a  urine  rich  in  urates  another  compli- 
cation may  occur,  due  to  tne  formation  of  a  ring  produced  by  the 
precipitated  uric  acid.  The  uric-acid  ring  does  not  lie,  like  the 
proteid  ring,  between  the  two  liquids,  but  somewhat  higher.  For 
this  reason  we  may  often  have  two  simultaneous  rings  with  urines 
rich  in  urates  and  yet  not  containing  very  much  proteid.  The 
disturbance  caused  by  uric  acid  is  easily  j)revented  by  diluting  the 
urine  with  1-2  vol.  water  before  performing  the  test.  The  uric 
acid  now  remains  in  solution,  and  the  delicacy  of  Heller's  test  is 
so  great  that  after  dilution  only  in  the  j^resence  of  insignificant 
traces  of  proteid  does  this  test  give  negative  results.  In  a  urine 
very  rich  in  urea  a  ring-like  separation  of  urea  nitrate  znay  ;il?o 
appear.     This  ring  consists  of  shinip/r  crystals,  and  it  does   aot 


TEST  FOR  PR0TEID8  IN  URINE.  533 

appear  in  the  previously  dilated  urine.  A  confusion  with  resinous 
4icids,  which  also  give  a  whitish  ring  with  this  test,  is  easily  pre- 
vented, since  these  acids  are  soluble  on  the  addition  of  ether.  Stir, 
add  ether  and  carefully  shake  the  contents  of  the  test-tube.  If  tiie 
cloudiuess  was  due  to  resinous  acids,  the  urine  becomes  gradually 
clear  and  on  evaporating  the  ether  a  sticky  residue  of  resinous  acids 
is  obtained.  A  liquid  which  contains  pure  mucin  does  not  give  a 
l^recipitate  with  this  test,  but  it  gives  a  more  or  less  strongly 
opalescent  ring,  which  disappears  on  stirring.  The  liquid  does  not 
contain  any  precipitate  after  stirring,  but  is  somewhat  opalescent. 
If  a  faint,  not  wholly  typical  reaction  is  obtained  with  Heller's 
test  after  some  time  with  undiluted  urine,  while  the  diluted  urine 
gives  a  pronounced  reaction  immediately,  then,  as  claimed  by  K. 
lIoRNER,'  a  nncleoalbumin  substance  is  present,  which  is  pre- 
vented from  precipitation  by  the  salts  of  the  undiluted  urine.  In 
this  case  proceed  as  described  below  in  regard  to  the  detection  of 
nncleoalbumin.  If  we  bear  in  mind  the  above-mentioned  possible 
errors  and  the  means  by  which  they  may  be  prevented,  there  is 
hardly  another  test  for  proteid  in  the  urine  which  is  at  the  same 
time  so  easily  performed,  so  delicate,  and  so  positive  as  Heller's. 
With  this  test  even  0.02  p.  m.  albumin  may  be  detected  without 
difficulty.  Still  the  student  should  not  be  satisfied  with  this  test 
alone,  but  apply  at  least  a  second  test,  such  as  the  heat  test.  In 
performing  this  test  the  (primary)  albumoses  are  also  precipitated. 

The  reaction  with  metapliosplioric  acid  (see  page  2G)  is  very 
convenient  and  easily  performed.  It  is  not  quite  so  delicate  and 
positive  as  Heller's  test.  The  albumoses  are  also  precipitated  by 
this  reagent. 

Reaction  with  Acetic  Acid  and  Potassium  Ferrocyanicle.  Treat 
the  urine  first  with  acetic  acid  until  about  2^,  and  then  add  drop 
by  drop  a  potassium  ferrocyanide  solution  (1:20),  carefully  avoid- 
ing an  excess.  This  test  is  very  good,  and  in  the  hands  of  experts 
it  is  even  more  delicate  than  Heller's.  In  the  presence  of  very 
small  quantities  of  proteid  it  requires  more  practice  and  dexterity 
than  Heller's,  as  the  relative  quantities  of  reagent,  proteid,  and 
acetic  acid  influence  the  result  of  the  test.  The  quantity  of  salts 
in  the  urine  also  seems  to  have  an  influence.  This  reagent  also 
precipitates  albumoses. 

Spiegler's  Wes^.  Spiegler  recommends  a  solution  of  8  parts 
mercuric  chloride,  4  parts  tartaric  acid,  20  parts  glycerin,  and  200 
parts  water  as  a  very  delicate  reagent  for  proteid  in  the  urine.  A 
test-tube  is  half  filled  with  this  reagent,  and  the  urine  allowed  to 
flow  upon  its  surface  drop  by  drop  from  a  pipette  along  the  wall  of 
the  test-tube.     In  the  presence  of  proteid  a  white  ring  is  obtained 

>  Hygiea,  Bd.  53.     See  Maly's  Jalaresber.,  Ld.  22,  S.  241. 
«  Wien.  klin.  Wochenschr.,  1893,  No.  2,  uad  Centralbl.  f.  klin.  Med.,  1893, 
Ho.  3. 


534:  THE   URINE. 

at  the  point  of  contact  between  the  two  liquids.     The  delicacy  of 
this  test  is  1 :  350000. 

The  use  of  precipitating  reagents  presumes  that  the  urine  to  be 
investigated  is  perfectly  clear,  especially  in  the  presence  of  only  very 
little  proteid.  The  urine  must  first  be  filtered.  This  is  not  easily 
done  with  urine  containing  bacteria,  but  a  clear  urine  may  be 
obtained,  as  suggested  by  A.  Jolles,'  by  shaking  the  urine  with 
infusorial  earth. 

The  different  color  reactions  cannot  be  directly  tised,  especially 
in  deep-colored  urines  which  only  contain  little  proteid.  The 
common  salt  of  the  urine  has  a  disturbing  action  on  Millon's 
reagent.  To  p,-ove  more  positively  the  presence  of  proteid,  the 
precipitate  obtained  in  the  boiling  test  may  be  filtered,  washed,  and 
then  tested  with  Millok"'s  reagent.  The  precipitate  may  also  be 
dissolved  in  dthite  alkali  and  the  biuret  test  applied  to  the  solution. 
The  presence  of  albumoses  or  peptones  in  the  urine  is  directly  tested 
for  by  this  last-mentioned  test.  In  testiug  the  urine  for  proteid 
one  must  never  be  satisfied  with  one  test  alone,  but  one  must  at 
least  apply  the  heat  test  and  Heller's  test  or  the  potassium- 
ferrocyanide  test.  In  using  the  heat  test  alone  the  albumoses  may 
be  easily  overlooked,  but  these  are  detected,  on  the  contrary,  by 
Heller's  test.  If  we  are  satisfied  with  this  last  test  or  the  potas- 
sium-ferrocyanide  test  alone,  we  have  no  sufficient  intimation  of  the 
kind  of  proteid  present,  whether  it  consists  of  albumoses  or  coagn- 
lable  proteid. 

For  practical  purposes  several  dry  reagents  for  proteid  have  been  recom- 
mended. Besides  the  metaphosphoric  acid  may  be  mentions  I  :  Stutzs  or  FtJR- 
bringer's  gelatin  capsules,^  which  contain  mercuric  choride,  sodium  chloride, 
and  citric  acid  ;  and  Geissler's  albumin-test  papers,  which  consist  of  strips  of 
filter- paper  which  have  been  dipped  in  a  solution  of  citric  acid  and  also  mer- 
curic-chloride and  potassium-iodide  solution  and  then  dried. 

If  the  presence  of  proteid  has  been  positively  proved  iu  the  urine 
by  the  above  tests,  it  then  remains  necessary  to  determine  the 
variety. 

The  detection  of  globulin  and  albumin.  In  detecting  ser- 
globulin  the  urine  is  exactly  neutralized,  filtered,  and  treated  with 
magnesium  sulphate  in  substance  until  it  is  completely  saturated  at 
the  ordinary  teni2)erature,  or  with  an  equal  volume  of  a  saturated 
neutral  solution  of  ammonium  sulphate.  In  both  cases  a  white, 
flocculent  precipitate  is  formed  in  the  presence  of  globulin.  In 
nsing  ammonium  sulphate  with  a  urine  rich  in  urates  a  precipitate 
consisting  of  ammonium  urate  may  separate.  This  precipitate  does 
not  appear  immediately,  but  only  after  a  certain  time,  and  it  must 
not  be  mistaken  for  the  globulin  precipitate.  In  detecting  ser- 
albumin heat  the  filtrate  from  the  globulin  precipitate  to  boiling- 
point  or  add  about  1^  acetic  acid  to  it  at  the  ordinary  temperature. 

>  Zeitschr.  f.  anal.  Chem.,  Bd.  29. 

'  In  regard  to  this  and  other  reagents  see  Huppert-Neubauer's  Harnanalyse,. 
10.  Autl..  S.  439. 


ALBUMOSES  AND   PEPTONE  IN  URTNE.  536 

Alhumoses  iiud  ])eptoncs  luive  beeu  repeatedly  found  in  the  urine 
in  different  diseases.  Unquestionable  observations  are  at  hand  on 
the  occurrence  of  albumoses  in  the  urine.  The  statements  in  regard 
to  the  occurrence  of  peptones '  date  in  part  from  a  time  when  the 
conception  of  albumoses  and  peptones  was  different  from  that  of 
the  present  day  and  in  part  they  are  based  upon  investigations 
using  insufficient  methods.  It  is  difficult  to  give  anything  positive 
m  regard  to  the  occurrence  of  so-called  true  peptone  in  the  urine, 
and  the  study  of  peptonuria  seems  to  require  thorough  investigation. 

In  detecting  albumoses  first  remove  all  coagnlable  proteids  by 
boiling  with  the  addition  of  acetic  acid.  The  filtrate  is  then  tested 
by  the  biuret  test,  and  when  this  gives  positive  results  apply  the 
three  previously  mentioned  albuniose  reagents  (page  34),  nitric 
acid,  acetic  acid  and  ^''otassium  ferrocyanide,  and  saturation  with 
common  salt  with  the  addition  of  acid.  The  albumoses  may  also  be 
precipitated  by  saturating  with  ammonium  sulphate  in  substance, 
and  the  detection  of  all)umoses  as  well  as  true  pe})tones  is  best  per- 
formed by  the  aid  of  this  salt.  According  to  Devoto  "  we  proceed 
as  follows: 

Devoto's  method.  The  coagnlable  proteid  is  precipitated  by 
ammonium  sulphate  as  directed  on  page  29.  The  precipitate  also 
contains  the  albumoses.  If  true  peptone  is  present,  it  is  found  in 
the  filtrate  and  may  be  tested  for  therein  by  means  of  the  biuret 
test.  The  precipitate  is  washed  with  a  saturated  solution  of 
ammonium  sulphate  and  then  treated  with  water.  The  coagnlable 
proteid  remains  undissolved,  while  the  albumoses  dissolve  and  mav 
be  tested  for  by  the  biuret  test.  The  deutero-albumose  are  never- 
theless not  completely  precipitated  by  the  ammonium  sulphate,  and 
a  mistaking  of  this  for  true  peptone  may  occur. 

In  testing  for  peptone  in  the  old  sense  we  make  use  of  Salkowski's'  modi- 
fication of  Hofmeister's'*  metliod.  50  c.  c.  of  the  urine  to  be  tested  is  aciiiified 
with  5  c.  c.  hydrochloric  acid,  precipitated  with  phospho-tungstic  acid  and 
warmed  on  a  wire  gauze.  As  soon  as  the  precipitate  is  converted  to  a  resinous 
mass  the  liquid  is  poured  off  as  well  as  possible  and  the  mass  washed  twice 
with  distilled  water.  It  is  then  dissolved  in  about  8  c.  c.  water  by  the  aid  of 
0.5  c.  c.  caustic  .soda  of  sp.  gr.  1.16  and  warmed  until  the  blue  solution  is  de- 
colorized (grayish  yellow  or  yellow).  This  solution  is  used  after  cooling  for 
the  biuret  test  by  the  addition  of  a  copper  solution  (1-2^)  drop  by  drop. 

At  the  present  time  we  have  no  trustworthy  method  for  the  quantitative 
estimation  of  albumoses  and  peptones  in  the  urine. 

'  In  regard  to  the  literature  on  albumoses  and  peptones  in  urine  see  Hup- 
pert-Neubauer-Harnanalyse,  10.  Aufi.,  S.  466  to  492;  also  A.  StofPregen,  Ueber 
das  Vorkommen  von  Pepton  im  Harn,  Sputum  undEiter.  Inaug.-Diss.  Dorpat, 
1891  ;  H.  Hirschfeldt,  Ein  Beitrag  zur  Frage  der  Peptonurie.  Inaug.-Diss. 
Dorpat,  1892;  and  especially  Stadelmann,  Uutersuchungeu  iiber  die  Peptonurie. 
Wiesbaden,  1894. 

»  Zeitschr.  f.  physiol.  Chem.,  Bd.  15. 

"  Centralbl.  f.  d.  med.  Wissensch.,  1894. 

*  "Zeitschr.  f.  physiol.  Chem.,  Bd.  4. 


536  THE   URINE. 

Quantitative  Estimation  of  Proteid  in  Urine.  ■  Of  all  the 
methods  proposed  thus  far,  the  coagulation  method  (boiling  with 
the  addition  of  acetic  acid)  when  performed  with  sufficient  care 
gives  the  best  results.  The  average  errors  need  never  amount  to 
more  than  0.01^,  and  it  is  generally  smaller.  In  using  this  method 
it  is  best  to  first  find  how  much  acetic  acid  must  be  added  to  a  small 
portion  of  urine,  which  has  been  previously  heated  on  the  water- 
bath,  to  completely  separate  the  proteid,  so  that  the  filtrate  does 
not  respond  to  Heller's  test.  Then  coagulate  20-50-100  c.  c. 
of  the  urine.  Pour  the  urine  into  a  beaker  and  heat  on  the  water- 
bath,  add  the  required  quantity  of  acetic  acid  slowly,  stirring  con- 
stantly, and  heat  at  the  same  time.  Filter  while  warm,  wash  first 
with  water,  then  with  alcohol  and  ether,  dry  and  weigh,  ash  and 
weigh,  again.  In  exact  determinations  the  filtrate  must  not  give 
Heller's  test. 

The  above-mentioned  method  of  Devoto  may  also  be  used  in 
the  quantitative  estimation  of  coagulable  proteids.  The  error 
originating  from  the  precipitation  of  uric  acid  and  other  urinary 
constituents  by  the  ammonium  sulphate  is  so  very  small  in  ordinary 
.rcases  where  the  precipitate  is  carefully  washed  that  it  is  unimpor- 
tant (Redelius  ').  In  the  presence  of  only  little  proteid  in  a  urine 
rich  in  uric  acid  it  may  on  the  contrary  be  quite  considerable. 

The  separate  estimation  of  globulins  and  albumins  is  done  by 
carefully  neutralizing  tlie  urine  and  prepcipitating  with  MgSO^ 
.added  to  saturation  (author),  or  simply  by  adding  an  equal  volume 
of  a  saturated  neutral  solution  of  ammonium  sulphate  (Hofmeistee 
and  PoHL^).  The  precipitate  consisting  of  globulin  is  thoroughly 
washed  with  a  saturated  magnesium  sulphate  or  half-saturated 
ammonium-sulphate  solution,  dried  continuously  at  110°  C,  boiled 
with  water,  extracted  with  alcohol  and  ether,  then  dried,  weighed, 
ashed,  and  weighed  again.  The  quantity  of  albumin  is  calculated 
as  the  difference  between  the  quantity  of  globulins  and  the  total 
proteids. 

Approximate  Estimation  of  Proteid  in  Uriiie.  Of  the  methods 
suggested  for  this  purpose  none  has  been  more  extensively  employed 
than  Esbach's. 

Esbach's''  method.  The  acidified  urine  (acidified  with  acetic 
acid)  is  poured  into  a  specially  graduated  tube  to  a  certain  mark 
and  then  the  reagent  (a  2^  citric-acid  and  Ifo  picric-acid  solution 
in  water)  is  added  to  a  second  mark,  the  tube  is  closed  with  a 
rubber  stopper  and  carefully  shaken,  avoiding  the  production  of 
froth.  The  tube  is  allowed  to  stand  twenty-four  hours,  and  then 
the  height  of  the  precipitate  in  the  graduated  tube  is  read  off.  The 
reading  gives  directly  the  quantity  of  proteid  in  1000  parts  of  the 

'  Upsala  Lakaref.s  Forh  ,  Bd.  27,  and  Maly's  Jahresber.,  Bd.  22. 
2  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  20. 

^  In  regard  to  the  literature  on  this  method  and  the  numerous  experiments 
to  determine  its  value  see  Huppert-Neubauer,  10.  Aufl.,  S.  853. 


NUGLEOALBUMIN  AND  MUCIN.  537 

nrine.  Urines  rich  in  proteid  ninst  first  be  diluted  with  water. 
The  results  obtained  by  this  method  are,  liowever,  dependent  upon 
the  temperature;  and  a  difference  in  temperature  of  5°  to  6.5°  C. 
may  in  urines  containing  a  medium  quantity  of  proteid  cause  an 
error  of  0.2-0.3^  deficiency  or  excess  (Christensen  and  Mygge). 
This  method  is  only  to  be  used  in  a  room  in  which  the  temperature 
may  be  kept  nearly  constant.  The  directions  for  the  use  of  the 
apparatus  accompany  it. 

Christensen's  and  Mygge's  '  method.  5  c.  c.  of  urine,  after 
being  acidified  with  2  drops  of  acetic  acid,  are  poured  into  a  some- 
what modified  burette  and  precipitated  with  a  certain  quantity  of 
a  Ifo  tannic-acid  solution  and  then  treated  with  1  c.  c.  of  mucilage. 
After  the  addition  of  water  to  a  certain  mark  and  after  inverting 
the  tube  several  times  a  uniform  emulsion  is  produced.  A  cylin- 
drical glass  filled  one  half  or  one  third  with  water  is  now  placed  on 
a  white  surface  having  a  number  of  close  black  lines  traced  upon  it, 
and  the  contents  of  the  burette  are  gradually  added  to  the  water 
with  constant  stirring,  until  by  close  observation  the  black  lines 
cannot  even  be  distinguished  from  the  white  spaces.  The  reading 
of  the  quantity  of  urine  emulsion  employed  gives  directly  the  quan- 
tity of  proteid  in  the  urine.  This  method  is  claimed  to  give  very 
good  results.     A  special  description  accompanies  each  apparatus.' 

The  method  proposed  by  Roberts  and  STOiiNiKOW  and  further  developed 
by  Brandberg,  though  somewhat  more  difficult  to  perform,  also  gives  satis- 
factory results.  The  density  methods  of  Lajng,  IIuppert,  and  Zahor'  are 
also  very  good.  The  last  consists  in  deteriuining  the  specific  gravity  before 
and  after  the  coagulation  of  the  proteids. 

Nucleoalbumin  and  Mucin.  Nucleoalbumin  seems  to  be  a  regular  ccnstituent 
of  urine,  although  ordinarily  it  only  occurs  in  very  small  quantities.  Mucin 
is  alleged  to  tccur  in  small  quantities  under  normal  conditions,  but  a])pears  in 
greater  quantities  in  catarrhal  affections  of  the  urinary  passages.  There  is  no 
doubt'*  that  cases  exist  in  which  true  mucin  occurs  in  the  urine;  in  most 
cases,  nevertheless,  we  are  doubtless  dealing  with  a  nucleoalbumin  similar  to 
mucin,  which  originates  in  the  kidneys  or  urinary  passages.^ 

To  detect  mucin  in  urine,  it  must  first  be  diluted  with  water  to  prevent  a 
precipitation  of  the  uric  acid  on  subsequent  addition  of  acid,  and  also  to  reduce 
the  solvent  action  of  the  common  salt  of  the  urine  on  the  mucin.  Now  add  an 
excess  of  acetic  acid.  The  precipitate  formed  is  purified  by  dissolving  in  water 
with  the  addition  of  a  little  alkali  and  reprecipitated  with  acetic  acid.  The 
precipitate  is  tested  with  the  ordinary  mucin  reagents.  To  avoid  mistaking 
mucin  for  nucleoalbumin,  which  is  similar  to  mucin,  the  precipitate  must  be 
tested  in  regard  to  its  behavior  on  boiling  with  dilute  mineral  acids.  If  no 
reducing  substance  is  formed  by  this  treatment,  it  contains  no  mucin.  To  de- 
tect nucleoalbumin  we  proceed    in  the  same  manner,  but  it  is  better  to  re- 

»  See  Malys  Jahresber.,  Bd.  18,  S.  314. 

*  The  apparatus  may  be  obtained  from  C.  Knudsen  in  Copenhagen. 

*  In  regard  to  these  methods  see  Huppert-Neul)auer's  Harnanalyse,  10.  Aufl., 
S.  845-853. 

"  See  B.  Malfatti,  Maly's  Jahresber.,  Bd.  21,  S.  22. 

'  In  regard  to  the  literature  see  Huppert-Neubauer,  S.  540 ;  Lonnberg, 
Upsala  Lakarefs  Forh.,  Bd.  25;  K.  Morner,  Hygiea,  Bd  53  ;  Obermayer, 
Centralbl.  f.  klin.  Med. ,  Bd.  13. 


538  THE    UliUE. 

move  the  salts  from  tlie  urine  by  means  of  dialysis  (K.  Mokneb  ').  Then  pre- 
cipitate with  not  too  much  acetic  acid.  To  determine  if  the  precipitate  con- 
sists of  nucleoalbumia  or  a  nucleoproteid,  we  test  for  xanthin  bases  alter  boiling 
with  an  acid.  Large  quantities  of  the  precipitate  are  necessary  for  this  pur- 
pose. 

Blood  and  Blood-coloring  Matters.  The  urine  may  contain 
blood  from  hemorrhage  in  the  kidneys  or  other  parts  of  the  urinary 
passages  (h^matukia).  In  these  cases,  when  the  quantity  of  blood 
is  not  very  small,  the  urine  is  more  or  less  cloudy  and  colored 
reddish,  yellowish  red,  dirty  red,  brownish  red,  or  dark  brown.  In 
recent  hemorrhages,  in  which  the  blood  has  not  decomposed,  the 
color  is  nearer  blood-red.  Blood-corpuscles  may  be  found  in  the 
sediment,  sometimes  also  blood-casts  and  smaller  or  larger  blood- 
clots. 

In  certain  cases  the  urine  contains  no  blood-corpuscles,  but  only 
dissolved  blood-coloring  matters,  haemoglobin  or,  and  indeed  quite 
often,  methsemoglobin  (hemoglobinuria).  The  blood-pigments 
appear  in  the  urine  under  different  conditions,  as  in  dissolution  of 
blood  in  poisoning  with  arseniuretted  hydrogen,  chlorates,  etc., 
after  serious  burns,  after  transfusion  of  blood,  and  also  in  the 
periodic  appearance  of  hsemoglobinuria  with  fever.  The  urine  may 
in  hsemoglobinuria  also  have  an  abundant  grayish-brown  sediment 
rich  in  .proteid  which  contains  the  remains  of  the  stromata  of  the 
red  blood-corpuscles.  In  animals  haemoglobinuria  may  be  produced 
by  many  causes  which  force  free  haemoglobin  into  the  plasma. 

To  detect  blood  in  the  urine  we  make  use  of  the  microscope,' 
spectroscope,  the  guaiacum  test,  and  Heller's  or  Heller-Teioh- 
mann's  test. 

Microscojyic  InvesiigaUon.  The  blood-corpuscles  may  remain 
undissolved  for  a  long  time  in  acid  urine;  in  alkaline  urine,  on  the 
contrary,  they  are  easily  changed  and  dissolved.  They  often  appear 
entirely  unchanged  in  the  sediment;  in  some  cases  they  are  dis- 
tended, and  in  others  unequally  pointed  or  jagged  like  a  thorn- 
apple.  In  hemorrhage  of  the  kidneys  a  cylindrical  clot  is  sometimes 
found  in  the  sediment,  which  is  covered  with  numerous  red  blood- 
corpuscles,  forming  casts  of  the  urinary  passages.  These  formations 
are  called  blood-oasts. 

The  spectroscopic  investigation  is  naturally  of  very  great  value; 
and  if  it  be  necessary  to  determine  not  only  the  presence  but  also 
the  kind  of  coloring  matter,  this  method  is  indispensable.  In 
regard  to  the  optical  behavior  of  the  various  blood-pigments  we 
must  refer  to  Chapter  VI , 

'  K.  Morner,  Hygiea,  Bd.  53. 


TESTS  FOR  BLOOD  PIGMENTS.  539 

Guaiacwn  Test.  Mix  in  a  test-tnbe  equal  volnmes  of  tincture 
of  guaiacnm  and  old  turpentine  which  has  become  strongly  ozon- 
ized by  the  action  of  air  under  the  influence  of  light.  To  this  mix- 
ture, which  must  not  have  the  slightest  blue  color,  add  the  urine 
to  be  tested.  In  the  presence  of  blood  or  blood-pigments,  first  a 
bluish-green  and  then  a  beautiful  blue  ring  appears  where  the  two 
liquids  meet.  On  shaking  the  mixture  it  becomes  more  or  less 
blue.  Xormal  urine  or  one  containing  proteid  does  not  give  this 
reaction.  For  the  explanation  of  this  we  must  refer  the  reader  to 
Chapter  VI,  page  134.  Urine  containing  pus,  although  no  blood 
is  present,  gives  a  blue  color  with  these  reagents;  but  in  this  case 
the  tincture  of  guaiacnm  alone,  without  turpentine,  is  colored  blue 
by  the  urine  (Vitali').  This  is  at  least  true  for  a  tincture  that 
has  been  exposed  for  some  time  to  the  action  of  air  and  sunlight. 
The  blue  color  produced  by  pus  diifers  from  that  produced  by  blood- 
coloring  matters  by  disapjjearing  on  heating  the  urine  to  boiling. 
A  urine  alkaline  by  decomposition  must  first  be  made  faintly  acid 
before  performing  the  reaction.  The  turpentine  should  be  kept 
exposed  to  sunlight,  while  the  tincture  of  guaiacnm  must  be  kept 
in  a  dark  glass  bottle.  These  reagents  to  be  of  use  must  be  con- 
trolled by  a  liquid  containing  blood.  This  test,  it  is  true,  in  posi- 
tive results  is  not  absolutely  decisive,  because  other  bodies  may  give 
a  blue  reaction;  but  when  properly  performed  it  is  so  extremely 
delicate  that  when  it  gives  negative  results  any  other  test  for  blood 
is  superfluous. 

Heller-Teichmaxn's  Test.  If  a  neutral  or  faintly  acid  urine 
containing  blood  is  heated  to  boiling,  we  always  obtain  a  mottled 
precipitate  consisting  of  albumin  and  hasmatin.  If  caustic  soda  is 
added  to  the  boiling-hot  test,  the  liquid  becomes  clear  and  turns 
green  when  examined  in  thin  layers  (due  to  h^ematin  alkali),  and  a 
red  precipitate,  appearing  green  by  reflected  light,  re-forms  which 
consists  of  earthy  phosphates  and  hfematiu.  This  reaction  is  called 
Heller's  blood-test.  If  this  precipitate  is  collected  after  a  time 
on  a  small  filter,  it  may  be  used  for  the  hremiu  test  (see  page  143). 
If  the  precijiitate  contains  only  a  little  blood-coloring  matter  with 
a  larger  quantity  of  earthy  phosphates,  then  wash  it  with  dilute 
acetic  acid,  which  dissolves  the  earthy  phosphates,  and  use  the 
residue  for  the  preparation  of  Teichmann's  hamin  crystals.  If, 
on  the  contrary,  the  amount  of  phosphates  is  very  small,  then  first 
add  a  little  CaCl^  solution  to  the  urine,  heat  to  boiling,  and  add 
simultaneously    with    the   caustic   potash    some   sodium-phosphate 

'  S^eMaly's  Jabresber.,  Bd.  18,  S.  326. 


oiO  THE   URINE. 

solution.  In  the  presence  of  only  yery  small  quantities  of  blood, 
first  make  the  urine  very  faintly  alkaline  with  ammonia,  add  tannic 
acid,  acidify  with  acetic  acid,  and  use  the  precipitate  in  the  prep- 
aration of  the  hsemin  crystals  (Steuve  '). 

Heematoporphyrin.  Since  the  occurrence  of  haematoporphyrin 
in  the  urine  in  various  diseases  has  been  made  very  probable  by 
several  investigators,  such  as  Neusser,  Stokyis,  MacMunk",  Le 
IS'OBEL,  EussEL,  CoPEMAE",  and  others,''  Salkowski  '  has  positively 
shown  the  presence  of  this  pigment  in  the  urine  after  sulphonal 
intoxications.  It  was  first  isolated  in  a  pure  crystalline  state  by  the 
AUTHOR^  from  the  urine  of  insane  women  after  sulphonal  intoxica- 
tion. According  to  Gaeeod  ^  traces  of  hgematoporphyrin  occur 
regularly  in  normal  urines.  It  is  also  found  in  the  urine  during 
different  diseases,  although  it  only  occurs  in  small  quantities.  It 
has  been  found  in  considerable  quantities  in  the  urine  after  intoxi- 
cation with  sulphonal. 

Urine  containing  hgematoporphyrin  is  sometimes  only  slightly 
colored,  while  in  other  cases,  as  for  example  after  the  use  of  sul- 
phonal, it  is  more  or  less  deep  red  in  color.  The  color  depends  in 
these  last-mentioned  cases,  in  greatest  part,  not  upon  hsematorpo- 
phyrin,  but  upon  other  red  or  reddish-brown  pigments,  which  have 
not  been  suflBciently  studied.  The  pathogenic  moment  of  hsemato- 
porphyrinuria  is  according  to  Stokvis  *  an  absorption  and  elimina- 
tion of  the  blood  emptied  into  the  intestinal  tract  or  present  there 
and  changed  into  hsBmatoporphyrin. 

In  detecting  hgematoporphyrin  the  urine  is  precipitated  with 
alkaline  barium-chloride  solution  (a  mixture  of  equal  volumes  of  a 
barium-hydrate  solution,  saturated  in  the  cold,  and  a  10^  barium- 
chloride  solotion  according  to  Salkowski),  or  the  urine  is  made 
strongly  alkaline  with  a  soda  solution,  according  to  Gaeeod,  which 
precipitates  the  earthy  phosphates.  In  both  cases  the  hgemato- 
porphyrin is  carried  down  with  the  precipitate,  while  urobilin  and 
certain  other  pigments  remain  in  solution.  The  washed  precipitate 
is  allowed  to  stand  some  time  at  the  temperature  of  the  room  with 

'  Zeitscbr.  f.  anal.  Cliem.,  Bd.  11. 

'  A  very  complete  index  of  the  literature  on  hsematoporpliyrin  in  the  urine 
may  be  found  by  R.  Zoja,  Su  qualcbe  pigmento  di  alcune  urine,  etc.,  in  Arch. 
Ital.  di  clin.  Med.,  1893. 

^Zeitschr.  f.  Physiol.  Chem.,  Bd.  15. 

4  Skand.  Arch.  f.  Physiol.,  Bd.  3. 

*  Journal  of  Physiol.,  vols.  13  and  17. 

«  Zeitschr.  f.  klin.  Med.,  Bd.  28. 


FU8  IN   URINE.  541 

alcohol  containing  hydrocliloric  or  sulphnric  acid  and  then  filtered. 
The  filtrate  shows  the  characteristic  spectrum  of  haematoporphyrin 
in  acid  solution,  and  gives  the  spectrum  of  alkaline  haematoporphyrin 
after  saturation  with  ammonia.  If  the  alcoholic  solution  is  mixed 
with  chloroform  and  a  large  quantity  of  water  added  and  carefully 
shaken,  sometimes  a  lower  layer  of  chloroform  is  obtained  which 
contains  very  pure  haematoporphyrin,  while  the  upper  layer  of 
alcohol  and  water  contains  the  other  j^igments  besides  some  haemato- 
porphyrin. 

Baumstakk  '  found  in  a  case  of  leprosy  two  cbaracteriatic  coloring  matters 
in  the  urine,  "  urorubroliaematin  "  and  ""urofuscobaematin,"  vLicli,  as  their 
names  indicate,  seem  to  stand  in  close  relationsliij)  to  tne  blood-coloring  matters. 
Urorubrolianndtin,  C68H94N8Fe.^Oo6,  contains  iron  and  shows  an  absnrption- 
band  in  front  of  D  and  a  broader  one  back  of  D.  in  alkaline  solution  it  shows 
four  bauds,  behind  D,  at  E,  beyond  F,  and  behind  O.  It  is  not  soluble  either 
in  water,  alcohol,  ether,  or  chloroform.  It  gives  a  beautiful  brownish-red  non- 
dichroitic  liquid  with  alkalies.  Urofuscoltcpviatin,  C68H106N8O26,  which  is  free 
from  iron,  shows  no  cliaracteristic  spectrum;  it  dissolves  in  alkalies,  ];roducing 
a  brown  color.  It  remains  to  be  proved  whether  these  two  pigments  are  related 
to  (impure)  hsematoporphyrin. 

Melanin.  In  the  presence  of  melanotic  cancers  dark  coloring  matters  are 
sometimes  eliminated  with  the  urine.  K.  Mokner'  has  isolated  two  pig- 
ments from  such  a  urine,  of  which  one  was  soluble  in  warm  50-75^  acetic  acid 
and  tlie  other,  on  the  contrary,  was  insoluble.  The  one  seemed  to  he  phymat- 
orhitsin  (see  Chapter  XVI).  Usually  the  urine  does  not  contain  any  melanin, 
but  a  chromogeu  of  melanin,  a  melnnogen.  In  such  cases  the  urine  gives 
Eiselt's  reaction,  becoming  dark-colored  wuth  oxidizing  ag^ents  such  as  cone, 
nitric  acid,  potassium  bichromate,  and  sulphuric  acid,  as  well  as  with  free  sul- 
phuric acid.  Urini-  containing  melanin  or  melanogen  is  colored  black  by  fer- 
ric-chloride solution  (v.  Jaksch'). 

Urorosein,  so  named  by  Nexcki,''  is  a  urinary  coloring  matter,  occurring  in 
various  diseases,  which  appears  on  the  acidification  of  the  urine  with  a  mineral 
acid,  and  which  is  taken  up  by  shaking  with  amyl-alcohol.  The  solution  shows 
an  ab.sorption-band  between  D  and  E.  This  pigment,  which  is  not  soluble  in 
chloroform  or  ether,  is  not  identical  with  indiizo-red.  Alkalies  decolorize  the 
solution  of  this  pigment  immediately,  find  it  is  also  rather  quickly  bleached  by 
light.  According  to  Z.\wadski  ^  urorosein  is  derived  from  urobilin  by  oxida- 
tion. Uroerythrin,  which  gives  a  rose-red  color  to  the  urinary  sediments 
especially  in  fevers,  seems  to  occur  also  in  urine  under  physiological  condi- 
tions. 

Pus  occurs  in  the  urine  in  different  infiammatory  affections, 
especially  in  catarrh  of  the  bladder  and  in  inflammation  of  the 
membrane  of  the  kidneys  or  the  urethra. 

Pus  is  best  detected  by  means  of  the  microscope.  The  pus-cells 
are  rather  easily  destroyed  in  alkaline  urines.  In  detecting  pus  we 
make  use  of  Doistxe's  ptis-test,  which  is  performed  in  the  following 
way:  Pour  off  the  urine  from  the  sediment  as  carefully  as  possible, 
place  a  small  piece  of  caustic  alkali  on  the  sediment,  and  stir.     If 

1  Pfluger's  Arch.,  Bd.  9. 

'  Zeitsclir.  f.  physiol.  Chem.,  Bd.  11. 

^  Ibid.,  Bd.  13. 

*  Nencki  und  Sieber,  Journal  f.  prakt.  Chem.  (N.  F.),  Bd.  26. 

*  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  28. 


542  TEE  UBINE. 

the  pus-cells  have  not  been  previonsly  changed,  the 'sediment  is 
converted  by  this  means  into  a  slimy  tough  mass. 

The  pus-corpuscles  swell  up  in  alkaline  urines,  dissolve,  or  at 
least  are  so  changed  that  they  cannot  be  recognized  under  the 
microscope.  The  urine  in  these  cases  is  more  or  less  slimy  or 
fibrous,  and  it  is  precipitated  in  large  flakes  by  acetic  acid,  so  that 
it  ]nay  possibly  be  mistaken  for  mucin.  The  closer  investigation 
of  the  precipitate  produced  by  acetic  acid,  and  especially  the 
appearance  or  non-apppearance  of  a  reducing  substance  after  boiling 
it  with  a  mineral  acid,  demonstrates  the  nature  of  the  precipitated 
substance.     Urine  containing  pus  always  contains  proteid. 

Bile-acids.  The  statements  in  regard  to  the  occurrence  of  bile- 
acids  in  the  urine  under  physiological  conditions  do  not  agree. 
According  to  Deagekdorff  and  Hone  traces  of  bile-acids  occur  in 
the  urine;  according  to  Mackat  and  v.  Udraxszky,^  they  do  not. 
Pathologically  they  are  present  in  the  urine  in  hepatogenic  icterus, 
although  not  always. 

Detection  of  Bile-acids  in  the  urine.  Pettenkofer's  test 
gives  the  most  decisive  reaction;  but  as  it  gives  similar  color 
reactions  with  other  bodies,  it  must  be  supplemented  by  the  spectro- 
scopic investigation.  The  direct  test  for  bile-acids  is  easy  after  the 
addition  of  traces  of  bile  to  a  normal  urine.  But  the  direct  detec- 
tion in  a  colored  icteric  urine  is  more  difficult  and  gives  very 
misleading  results;  the  bile-acid  must  therefore  always  be  isolated 
from  the  urine.  This  may  be  done  by  the  following  method  of 
Hoppe-Setler,  which  is  slightly  modified  in  non-essential  points. 

Hoppe-Seyler's  Method.  Strongly  concentrate  the  urine, 
and  extract  the  residue  with  strong  alcohol.  The  filtrate  is  freed 
from  alcohol  by  evaporation  and  then  precipitated  by  basic  lead 
acetate  and  ammonia.  The  washed  precipitate  is  treated  with 
boiling  alcohol,  filtered  hot,  the  filtrate  treated  with  a  few  drops  of 
soda  solution,  and  evaporated  to  dryness.  The  dry  residue  is 
extracted  with  absolute  alcohol,  filtered,  and  an  excess  of  ether 
added.  The  amorphous  or,  after  a  longer  time,  crystalline  precipi-. 
tate  consisting  of  alkali-salts  of  the  biliary  acids  is  used  in  perform- 
ing Pettenkofer's  test. 

Bile-coloring  matters  occur  in  the  urine  in  different  forms  of 
icterus.  A  urine  containing  bile-coloring  matters  is  always  abnor- 
mally colored — yellow,  yellowish  brown,  deep  brown,  greenish 
yellow,  greenish  brown,  or  nearly  pure  green.  On  shaking  it 
froths,  and  the  bubbles  are  yellow  or  yellowish  green  in  color.  As 
a  rule  icteric  urine  is  somewhat  cloudy,  and  the  sediment  is  fre- 
quently, especially  when  it  contains  epithelium-cells,  rather  strongly 

'  Cited  from  Huppert-Neubauer,  Harnanaljse,  10.  Aufl,,  S.  229. 


TESTS  FOR  BILE  PIGMENTS.  543 

colored   by  the  bile-pigments.     In   regard   to   the   occurrence   of 
urobilin  in  icteric  urine  see  page  501. 

Detection  of  bile-coloring  matters  in  urine.  Many  tests  have 
been  proposed  for  the  detection  of  bile-coloring  matters.  Ordinarily 
we  obtain  the  best  results  either  with  Gmelin's  or  with  Huppert's 
test. 

Gmelin's  ted  may  be  applied  directly  to  the  urine;  but  it  is 
better  to  use  Rosenbach's  modification.  Filter  the  urine  through 
a  very  small  filter,  which  is  deep-colored  from  the  retained  epithe- 
lium-cells and  bodies  of  tliat  kind.  After  the  liquid  has  entirely 
passed  through  apply  to  the  inside  of  the  filter  a  drop  of  nitric  acid 
which  contains  only  very  little  nitrous  acid.  A  pale-yellow  spot 
will  be  formed  which  is  surrounded  by  colored  rings  which  appear 
yellowish  red,  violet,  blue,  and  green  from  within  outward.  This 
modification  is  very  delicate,  and  it  is  hardly  possible  to  mistake 
indican  and  other  coloring  matters  for  the  bile-pigments.  Several 
other  modifications  of  Gmeliist's  test  on  the  urine  directly,  as  with 
concentrated  sulphuric  acid  and  nitrate,  etc.,  have  been  proposed, 
but  they  are  neither  simpler  nor  more  delicate  than  Eosenbach's 
modification. 

Huppert's  Beactioii.  In  a  dark-colored  urine  or  one  rich  in 
indican  we  do  not  always  obtain  good  results  with  Gmelin's  test. 
In  such  cases,  as  also  in  urines  containing  blood-coloring  matters  at 
the  same  time,  the  urine  is  treated  with  lime-water,  or  first  with 
some  CaClj  solution,  and  then  with  a  solution  of  soda  or  ammonium 
carbonate.  The  precipitate  which  contains  the  bile-coloring  matters 
is  filtered  and  used  for  Huppert's  test  (see  page  235). 

The  precipitate  consisting  of  lime-pigments  may  also  be  shaken 
out  with  chloroform  after  washing  in  water  and  after  being  acidified 
with  acetic  acid.  The  bilirubin  is  taken  up  by  the  chloroform, 
which  is  colored  yellow  thereby,  while  the  acetic-acid  solution  is 
colored  green  by  the  biliverdin.  Both  solutions  may  then  be  used 
for  Gmelin's  -.est  (Hoppe-Setler),  and  small  quantities  of  bile- 
coloring  matters  may  be  detected  in  this  way.  The  lime-pigments 
may,  according  to  Hilger,  also  be  used  directly  for  Gmelin's  test 
in  the  following  way:  Spread  them  on  a  porcelain  dish  in  a  thin 
layer,  and  add  carefully  a  drop  of  nitric  acid.  The  reaction 
generally  appears  very  beautiful. 

Jolles'  Method.'  Place  50  c.  c.  of  the  urine  in  a  cylinder  with 
a  glass  stopper,  add  a  few  drops  of  10^  hydrochloric  acid  and  an 
excess  of  a  barium-chloride  solution  with  5  c.  c.  chloroform,  and 
shake  thoroughly  for  a  few  minutes.  After  about  10  minutes 
remove  the  chloroform  and  the  precipitate  by  means  of  a  pipette 
and  place  in  a  test-tube  and  heat  on  the  water-bath  at  about  80°  C. 

'  Zeitschr.  f.  pliysiol.  Chem.,  Bd  18,  S.  545.  This  contains  the  literature 
on  all  the  known  tests  for  bile-pigments  with  the  exception  of  Stokvis's  test, 
which  may  be  found  in  Maly's  Jahresber.,  Bd.  12,  S.  236. 


544  THE   URINE. 

After  the  evaporation  of  the  chloroform  carefully  decant  the  liquid 
from  the  precipitate  and  allow  3  drops  concentrated  nitric  acid  con- 
taining \  fuming  nitric  acid  to  flow  down  the  sides  of  the  test-tube. 
In  the  presence  of  bile-pigments  the  characteristic  colored  rings  are 
obtained,  and  this  modification,  according  to  Jolles,  is  the  most 
delicate  of  all.  tests  for  bile-pigments. 

Stokvis's  reaction  is  especially  valuable  in  those  cases  in  which 
the  urine  contains  only  very  little  bile-coloring  matter  together  with 
larger  quantities  of  other  coloring  matters.  The  test  is  performed 
as  follows:  20-30  c.  c.  urine  are  treated  with  5-10  c.  c.  of  a  solu- 
tion of  zinc  acetate  (1  :  5).  The  precipitate  is  washed  on  a  small 
filter  with  water  and  then  dissolved  in  a  little  ammonia.  The  new 
filtrate  gives,  directly  or  after  it  has  stood  a  short  time  in  the  air 
until  it  has  a  peculiar  brownish-green  color,  the  absorption-bands 
of  bilicyanin  (see  page  235). 

Many  other  reactions  for  bile-coloring  matters  in  the  urine  have 
been  proposed;  but  as  the  above-mentioned  are  sufficient,  it  is 
perhaps  only  necessary  to  give  here  a  few  of  the  other  reactions, 
without  entering  into  details. 

Ultzmann's  reaction  consists  in  treating  about  10  c.  c.  of  the  urine  with 
3-4  c.  c.  concentrated  caustic-potash  solution  and  then  acidifying  with  hydro- 
chloric acid.     The  urine  will  become  a  beautiful  green. 

Smith's  Reaction.  Pour  carefully  over  the  urine  tincture  of  iodine,  where- 
by a  green  ring  appears  between  the  two  liquids.  You  may  also  shake  the 
urine  with  tim  ture  of  iodine  until  it  has  a  green  color. 

Eiirlich's  Tent.  First  mis  the  urine  with  an  equal  volume  of  dilute  acetic 
acid  and  then  add  drop  by  drop  a  solution  of  sulpho-diazobenzol.  The  a';id 
mixture  becomes  dark  red  in  the  presence  of  bilirubin,  and  this  color  becomes 
bluish  violet  on  the  addition  of  glacial  acetic  acid.  Tl:e  sulpho-diazobenzol  is 
prepared  with  1  grm.  sulphanilic  acid,  15  c.  c.  hydrochloric  acid,  and  0.1  grm. 
sodium  nitrite;  this  solution  is  diluted  to  1  litre  with  water. 

Medicinal  coloring  matters  produced  from  santonin,  rhubarb,  senna, 
etc.,  may  give  an  abnormal  color  to  the  urine  which  may  be  mistaken  for  bile- 
coloring  matters  or,  in  alkaline  urines,  perhaps  for  blood-coloring  matters.  If 
hydrochloric  acid  is  added  to  such  a  urine,  it  becomes  yellow  or  pale  yellow, 
while  on  the  addition  of  an  excess  of  alkali  it  becomes  more  or  less  beautifully 
red. 


Sugar  in  Urine. 

The  occurrence  of  traces  of  grape-sugar  in  the  urine  of  perfectly 
healthy  persons  has  been,  as  above  stated  (page  505),  quite  posi- 
tively proved.  If  sugar  appears  in  the  urine  in  constant  and 
especially  in  large  quantities,  it  must  be  considered  as  an  abnormal 
constituent.  We  have  given  in  a  previous  chapter  several  of  the 
most  important  conditions  which  cause  glycosuria  in  man  and 
animals,  and  we  must  refer  the  reader  to  Chapters  VIII  and  IX  for 
the  essential  facts  in  regard  to  the  appearance  of  sugar  in  the  urine. 

In  man  the  appearance  of  glucose  in  the  urine  has  been  ob- 


DETECTION  OF  SUGAR.  545 

iseryed  in  numerous  and  various  pathological  conditions,  such  as 
lesions  of  the  brain  and  especially  of  the  medulla  oblongata,  abnor- 
mal circulation  in  the  abdomen,  diseases  of  the  heart  and  lungs, 
diseases  of  the  liver,  cholera,  and  many  other  diseases.  The 
continued  presence  of  sugar  in  human  urine,  sometimes  in  very 
considerable  quantities,  occurs  in  diabetes  mellitus.  In  this 
disease  there  may  be  an  elimination  of  1  kilogramme  or  even  more 
of  grape-sugar  duriug  the  "21  hours.  In  the  beginning  of  the 
disease,  when  the  quantity  of  sugar  is  still  very  small,  the  urine 
often  does  not  appear  abnormal.  In  more  developed,  typical  cases 
the  quantity  of  urine  voided  increases  considerably,  to  3-6-lU  litres 
per  2-i  hours.  The  percentage  of  the  physiological  constituents  is 
as  a  rule  very  low,  while  their  absolute  daily  quantity  is  increased. 
The  urine  is  pale,  but  of  a  high  specific  gravity,  1.030-1.040  or 
even  higher.  The  high  specific  gravity  depends  upon  the  quantity 
of  sugar  present,  which  varies  in  different  cases,  but  may  be  as 
high  as  lO'fc.  The  urine  is  therefore  characterized  in  typical  cases 
of  diabetes  by  the  very  large  quantity  voided,  by  the  pale  color 
and  high  specific  gravity,  and  by  its  containing  sugar. 

That  the  urine  after  the  introduction  of  certain  medicines  or 
poisonous  bodies  into  the  system  contains  reducing  bodies,  con- 
jugated glycuronic  acids,  which  may  be  mistaken  for  sugar,  has 
already  been  mentioned. 

The  properties  and  reactions  of  glucose  have  been  treated  of  in 
a  previous  chapter,  and  it  remains  but  to  mention  the  methods  of 
detecting  and  quantitatively  estimating  glucose  in  the  urine. 

The  detection  of  sugar  in  the  urine  is  ordinarily,  in  the  presence 
of  not  too  small  quautiiies  of  sugar,  a  very  simple  task.  The  pres- 
ence of  only  very  small  qaantities  may  make  its  detection  sometimes 
very  difficult  and  laborious.  A  urine  containing  proteid  must  first 
have  the  proteid  removed  by  coagulation  with  acetic  acid  and  heat 
before  it  can  be  tested  for  sugar. 

The  tests  which  are  most  frequently  employed  and  are  especially 
recommended  are  as  follows : 

Trommer's  Test.  In  a  typical  diabetic  urine  or  one  rich  int 
sugar  this  test  succeeds  well,  and  it  may  be  performed  in  the^ 
manner  suggested  on  page  60.  This  test  may  lead  to  very  great 
mistakes  in  urines  poor  in  sugar,  especially  when  they  have  at  the 
same  time  normal  or  increased  amounts  of  physiological  con- 
stituents, and  therefore  it  cannot  be  recommended  to  physicians  or 
to  persons  inexperienced  in  such  work.  Normal  urine  contains- 
reducing  substances,  such  as  uric  acid,  creatinin,  and  others,  andi 


,546  THE   URINE. 

therefore  a  reduction  takes  place  with  all  urine  on  using  this  test. 
We  do  not  generally  have  a  separation  of  copper  suboxide,  but  still 
if  we  vary  the  proportion  of  the  alkali  to  the  copper  sulphate  and 
boil  we  often  have  an  actual  separation  of  suboxide  in  normal 
urines,  or  we  obtain  a  peculiar  yellowish-red  liquid  due  to  finely 
divided  hydrated  suboxide.  This  occurs  especially  on  the  addition 
of  much  alkali  or  too  much  copper  sulphate,  and  by  careless 
manipulation  the  inexperienced  worker  may  therefore  sometimes 
obtain  apparently  positive  results  in  a  normal  urine.  On  the  other 
hand,  as  urine  contains  substances,  such  as  creatinin  and  ammonia 
(from  the  urea),  which  in  the  presence  of  only  little  sugar  may  keep 
the  copper  suboxide  in  solution,  he  may  easily  overlook  small 
quantities  of  sugar  that  may  be  present. 

Trommer's  test  may  of  course  be  made  positive  and  useful, 
even  in  the  presence  of  very  small  quantities  of  sugar,  by  using  the 
modification  suggested  by  Worm  Muller.  As  this  modification 
is  rather  complicated,  and  requires  much  practice  and  exactness, 
it  is  probably  rarely  employed  by  the  busy  physician.  The  follow- 
ing test  is  to  be  preferred: 

Almen's  bismuth  test,  which  recently  has  been  incorrectly  called 
J^tlander's  test,  is  performed  with  the  alkaline  bismuth  solution 
prepared  as  above  described  (page  69).  For  each  test  10  c.  c.  of 
urine  are  taken  and  treated  with  1  c.  c.  of  the  bismuth  solution 
and  boiled  for  a  few  minutes.  In  the  presence  of  sugar  the  urine 
becomes  darker  yellow  or  yellowish  brown.  Then  it  grows  darker, 
cloudy,  dark  brown,  or  nearly  black,  and  non- transparent.  After 
a  shorter  or  longer  time  a  black  deposit  appears,  the  supernatant 
liquid  gradually  clears,  but  still  remains  colored.  In  the  presence 
of  only  very  little  sugar  the  test  is  not  black  or  dark  brown,  but 
simply  deeper-colored,  and  not  until  after  some  time  do  we  see  on 
the  upper  layer  of  the  phosphate  precipitate  a  dark  or  black  edge 
(of  bi.sniQth?).  In  the  presence  of  much  sugar  a  larger  amount  of 
reagent  may  be  used  without  disadvantage.  In  a  urine  poor  in 
sugar  we  must  use  only  1  c.  c.  of  the  reagent  for  every  10  c.  c.  of 
the  urine. 

This  test  shows  the  presence  of  1-0.5  p.  m.  sugar  in  the  urine. 
The  sources  of  error  which  interfere  in  Trommer's  test,  such  as 
the  presence  of  uric  acid  and  creatinin,  entirely  disappear  in  this 
test.  The  bismuth  test  is,  besides,  more  easily  performed,  and  it  is 
therefore  to  be  recommended  to  the  physician.  Small  quantities  of 
proieid  do  not  intei'fere  with  this  test;  large  quantities  may  give 
rise  to  an  error  by  forming  bismuth  sulphide,  and  therefore  must 
he  removed  by  coagulation. 

In  using  this  method  it  must  not  be  overlooked  that  it  is,  like 
Trommer's  test,  a  reduction  test,  and  it  consequently  may  show, 
besides  sugar,  certain  other  reducing  substances.  Such  bodies  are 
certain  conjugated  glycuronic  acids  which  may  appear  in  the  urine. 
Positive  results  have  been  obtained  with  the  bismuth  test  on  urine 


DETECTION  OF  SUGAR.  547 

after  the  use  of  several  medicines  such  as  rhubarb,  senna,  antipyrin, 
kairin,  salol,  turpentine,  and  others.  From  this  it  follows  that  we 
ehould  never  be  satisfied  with  this  test  aloue,  especially  when  the 
reduction  is  not  very  great.  When  this  test  gives  negative  results 
we  can  consider  the  urine  as  free  from  sugar  from  a  clinical  stand- 
point, and  when  it  gives  positive  results  other  tests  must  be  applied. 
Among  these  the  fermentation  test  is  of  special  value. 

Fermentation  Test.  On  using  this  test  we  must  proceed  in. 
various  ways,  according  as  the  bismuth  test  shows  small  or  large 
quantities.  If  a  rather  strong  reduction  is  obtained,  the  urine  may 
be  treated  with  yeast  and  the  presence  of  sugar  determined  by  the 
generation  of  carbon  dioxide.  In  this  case  the  acid  urine,  or  that 
faintly  acidified  with  tartaric  acid,  is  treated  with  yeast  which 
has  previously  been  washed  by  decantation  with  water.  Pour  this 
urine  to  which  the  yeast  has  been  added  into  a  Schkotter's  gas- 
burette,  or  glass  tube  with  the  open  end  ground,  close  with  the 
thumb,  and  open  under  the  surface  of  mercury  contained  in  a  dish. 
As  the  fermentation  proceeds,  the  carbon  dioxide  collects  in  the 
upper  part  of  the  tube,  while  a  corresponding  quantity  of  liquid  is 
expelled  below.  As  a  control  in  this  case  two  other  similar  tests 
must  be  made,  one  with  normal  urine  and  yeast  to  learn  the  quan- 
tity of  gas  usually  developed,  and  the  other  with  a  sugar  solution 
and  yeast  to  determine  the  activity  of  the  yeast. 

If,  on  the  contrary,  we  find  only  a  faint  reduction  with  the 
bismuth  test,  no  positive  conclusion  can  be  drawn  from  the  absence 
of  any  carbon  dioxide  or  the  appearance  of  a  very  insignificant 
quantity.  In  this  case  proceed  in  the  following  way:  Treat  the  acid 
urine,  or  the  urine  which  has  been  faintly  acidified  with  tartaric 
acid,  with  yeast  whose  activity  has  been  tested  by  a  special  test  on 
a  sugar  solution,  and  allow  it  to  stand  24-48  hours  at  the  tempera- 
ture of  the  room,  or,  better,  at  a  little  higher  temperature.  After 
this  time  test  again  with  the  bismuth  test,  and  if  the  reaction  now 
gives  negative  results,  then  sugar  was  previously  present.  But  if 
the  reaction  continues  to  give  positive  results,  then  it  shows — if  the 
yeast  is  active — the  presence  of  other  reducing,  unfermentable 
bodies.  There  remains  of  course  the  possibility  that  tlie  urine  also 
contains  some  sugar  besides  tliese  bodies.  This  possibility  may  be 
determined  by  the  following  test: 

Plteniilliydrazin  Ted.  According  to  v.  Jaksch,'  this  test  is 
performed  in  the  following  way:  Add  in  a  test-tube  containing  8-10 
c.  c.  of  the  urine  two  knife-points  of  phenylhydrazin  hydrochloride 
and  three  knife-points  sodium  acetate,  and  when  the  added  salts  do 
not  dissolve  on  warming  add  more  water.  The  mixture  is  heated 
in  boiling  water  and  kept  there  for  one  hour  to  avoid  a  confusioa 
with  pheujlhydrazin-glycuronic  acid  (v.  Jaksch  and  Hirschl). 
It  is  then  poured  into  a  beidiier  of  cold  water.  If  the  quantity  of 
sugar  present  is  not  too  small,  a  yellow  crystalline  precipitate  is  now 
1  V.  Jaksch,  Klin.  Diagnostik,  4.  Aufl.,  S.  375. 


54:8  THE   URINE. 

obtaiaed.  If  the  precipitate  appears  amorplions,  there  are  fonnd, 
on  lookiag  at  it  under  the  microscope,  yellow  needles  singly  and 
in  groups.  If  very  little  sugar  is  present,  pour  the  test  into  a 
coaical  glass  and  examine  the  sediment.  In  this  case  at  least  a  few 
phenylglucosazone  crystals  are  found,  while  the  occurrence  of 
smaller  and  larger  yellow  plates  or  highly  refractive  brown  globules 
do  not  show  the  presence  of  sugar.  According  to  Y.  Jaksch,  this 
reaction  is  very  reliable,  and  by  it  the  presence  of  0.3  p.  m.  sugar 
can  be  detected  (Rosenberg,'  Geyer*). 

Ttie  value  of  this  test  has  been  considerably  debated,  and  the 
objection  has  been  made  that  glycuronic  acid  also  gives  a  similar 
precipitate.  A  confounding  with  glycuronic  acid  is,  according  to- 
HiRSCHL,^  not  to  be  apprehended  when  it  is  not  heated  in  the 
water-bath  for  too  short  a  time  (one  hour).  Kisteemann  *  found 
this  precaution  insufficient,  and  Roos  ^  states  that  the  phenyl- 
liydrazin  test  always  gives  a  positive  result  with  human  urine.  la 
doubtful  cases  where  we  wish  to  be  quite  positiv^e,  prepare  the 
crystals  from  a  large  quantity  of  urine,  dissolve  them  on  the  filter 
by  pouring  o^er  them  hot  alcohol,  treat  the  filtrate  with  water,  and 
boil  off  the  alcohol.  11  the  characteristic  yellow  crystalline  needles, 
whose  melting-point  ('-i04-205°  C.)  is  also  determined,  are  now 
obtained,  then  this  test  is  decisive  for  the  presence  of  sugar.  It 
must  not  be  forgotten  that  Isevulose  gives  the  same  osazone  as 
grape-sugar,  and  that  a  further  investigation  is  necessary  in  certain. 
cases. 

Polarization.  This  test  differentiates  between  dextrose,  which 
polarizes  to  the  right,  and  Isevulose,  which  polarizes  to  the  left. 
The  polariscopic  investigation  is  of  great  value,  especially  as  in 
many  cases  it  quickly  differentiates  between  sugar  and  other  reduc- 
ing, Isevogyrate  substances,  such  as  conjugated  glycuronic  acid. 
In  the  presence  of  only  very  little  sugar  the  value  of  this  test 
depends  on  the  delicacy  of  the  instrument  and  the  dexterity  of  the 
observer;  therefore  this  method  is  perhaps  inferior  in  most  cases  to 
the  bismuth  test  or  to  the  phenylhydrazin  test. 

If  small  quantities  of  sugar  are  to  be  isolated  from  the  urine, 
precipitate  the  urine  first  with  sugar  of  lead,  filter,  precipitate  the 
filtrate  with  ammoniacal  basic  lead  acetate,  wash  this  precipitate 
with  water,  decompose  it  with  H^S  when  suspended  in  water,  con- 
centrate the  filtrate,  treat  it  with  strong  alcohol  until  it  is  80  vol. 
per  cent,  filter  when  necessary,  and  add  an  alcoholic  caustic-alkali 
solution.     Dissolve  the  precipitate  consisting  of  saccharates  in  a 

'  Deutsch.  med.  Wochenschr.,  1888, 

s  Wien.  med.  Presse,  1889,  S.  1688.  Cited  from  Roos,  Zeitschr.  f.  physioL 
Chem.,  Bd.  15,  S.  524. 

3  Zeitschr.  f.  physiol.  Cbem.,  Bd.  14. 

*  Deutscli.  Arcb.  f.  Iclin.  Med.,  Bd.  50.  Cited  from  Maly's  Jahresber.,  Bd. 
22,  S.  229. 

'  Zeitschr.  f.  physiol.  Chem.,  Bd.  15. 


QUANTITATIVE  ESTIMATION  OF  SUGAR.  549 

little  water,  j^recipitate  the  potash  by  an  excess  of  tartaric  acid, 
neutralize  the  filtrate  with  calcium  carbonate  in  the  cold,  and  filter. 
The  filtrate  may  be  used  for  testing  with  the  polariscope  as  well  as 
in  the  fermentation,  bismuth,  and  phenylhydraziti  tests.  The 
presence  of  grape-sugar  may  be  detected  by  this  same  process  in 
iinimal  fluids  or  tissues  from  which  the  proteids  have  been  removed 
by  coagulation  or  by  the  addition  of  alcohol. 

Por  the  physician,  who  naturally  wants  specially  simple  and 
quick  methods,  the  bismuth  test  must  be  especially  recommended. 
If  this  test  gives  negative  results,  the  urine  is  to  be  considered  as 
free  from  sugar  in  a  clinical  sense.  If  it  gives  positive  lesults,  the 
presence  of  sugar  must  be  controlled  by  other  tests,  especially  by 
the  fermentation  test. 

Other  tests  for  sugar,  as,  for  example,  tlie  reaction  with  orthonitrophenyl- 
propicjlic  ac-id,  i  icric  acid,  diazobeuzol-snlphonic  acid,  are  superfluous.  The 
reaction  with  (tr-uaphthol,  which  is  a  reaction  for  carbohydrates  in  general,  for 
glycuronic  acid  and  mucin,  may,  because  of  its  extreme  delicacy,  give  rise  to 
mistakes,  and  is  therefore  not  to  be  recommended  to  physicians.  Normal 
urines  give  this  test,  and  if  the  strongly  diluted  urine  gives  this  reaction  we 
may  consider  the  presence  of  large  quantities  of  carbohydrates.  In  these  cases 
we  get  more  positive  results  by  using  other  tests.  This  test  requires  great 
■cleanliness,  and  it  has  this  inconvenience,  that  it  is  very  difficult  to  get  suffi- 
ciently pure  sulphuric  acid,  and  sometimes  indeed  perfectly  pure  (V-naphthol. 
Several  investigators,  such  as  v.  UdrAnsky,  Luthek,  Rods,  and  Tkeupel,' 
have  investigated  this  test  in  regard  to  its  applicability  as  an  approximate  test 
for  carbohydrates  in  the  urine. 

Quantitative  Estimatio7i  of  Sugar  in  the  urine.  The  urine  for 
such  an  estimation  must  first  be  tested  for  proteid,  and  if  any  be 
present  it  must  be  removed  by  coagulation  and  the  addition  of 
acetic  acid,  care  being  taken  not  to  increase  or  diminish  the  original 
volume  of  urine.  The  quantity  of  sugar  may  be  determined  by 
TITRATION  with  Fehling's  or  Knapp's  solution,  by  fermenta- 
tion, or  by  POLARIZATION. 

The  titration  liquids  not  only  react  with  sugar,  but  also  with 
certain  other  reducing  substances,  and  on  this  account  the  titration 
methods  give  rather  high  results.  When  large  quantities  of  sugar 
are  present,  as  in  typical  diabetic  urine,  which  generally  contains  a 
lower  percentage  of  normal  reducing  constituents,  this  is  indeed  of 
little  account;  but  when  small  quantities  of  sugar  are  present  in  an 
otherwise  normal  urine,  the  mistake  may,  on  the  contrary,  be  im- 
portant, as  the  reducing  power  of  normal  urine  may  correspond  to 
5  p.  m.  grape-sugar  (see  page  506).  In  such  cases  the  titration 
method  must  be  employed  in  connection  with  the  fermentation 
method,  which  will  be  described  later.  It  is  to  be  remarked  that 
in  typical  diabetic  urines  with  considerable  quantities  of  sugar  the 
titration  with  Fehling's  solution  is  just  as  reliable  as  with 
Knapp's  solution.  When  the  urine,  on  the  contrary,  contains  only 
little  sugar  with  normal  amounts  of  physiological  constituents,  then 

'  See  Roos  and  Treupel,  Zeitschr.  f.  physiol.  (hem.,  Bdd.  15  u.  16. 


550  TBE  URINE. 

tlie  titration  with  Fehling's  solution  is  more  difficult,  indeed  in 
certain  cases  almost  impossible,  the  results  being  very  uncertain. 
In  such  cases  Knapp's  method  gives  good  results,  according  to 
Worm  Muller  and  his  pupils. ' 

The  TITRATION  with  Feeling's  solution  depends  on  the 
power  of  sugar  to  reduce  copper  oxide  in  alkaline  solutions.  For 
this  we  formerly  employed  a  solution  which  contained  a  mixture  of 
copper  sulphate,  Eocheile  salt,  and  sodium  or  potassium  hydrate 
(Fehling's  solution) ;  but  as  such  a  solution  readily  changes,  we 
now  prepare  a  copper-sulphate  sokition  and  an  alkaline  Rochelle- 
salt  solution  separately,  and  mix  equal  volumes  of  the  two  solutions 
before  using. 

The  concentration  of  the  copper-sulphate  solution  is  such  that 
10  c.  c.  of  this  solution  is  reduced  by  0,05  grm.  grape-sugar.  The 
copper-sulphate  solution  contains  34.65  grms.  pure,  crystallized, 
non-efflorescent  copper  sulphate  in  1  litre.  The  sulphate  is  crystal- 
lized from  a  hot  saturated  solution  by  cooling  and  stirring;  and  the 
crystals  are  separated  from  the  mother-liquor  and  pressed  between 
blotting-paper  until  dry.  The  Rochelle-salt  solution  is  prepared  by 
dissolving  173  grms.  of  the  salt  in  350  c.  c.  water,  adding  600  c.  c. 
of  a  caustic-soda  solution  of  a  specific  gravity  of  1.12,  and  diluting 
with  water  to  1  litre.  According  to  Worm  Muller,  these  three 
liquids — Eochelle-salt  solution,  caustic  soda,  and  water — should  be 
separately  boiled  before  mixing  together.  For  each  titration  mix 
in  a  small  flask  or  porcelain  dish  exactly  10  c.  c.  of  the  copper- 
sulphate  solution  and  10  c.  c.  of  the  alkaline  Eochelle-salt  solution 
and  add  30  c.  c.  water. 

The  urine  free  from  proteid  is  diluted  before  the  titration  with 
water  so  that  10  c.  c.  of  the  copper  solution  requires  between  5  and 
10  c.  c.  of  the  diluted  urine,  which  corresponds  to  between  1  and 
a  sugar.  A  urine  of  a  specific  gravity  of  1.030  may  be  diluted 
five  times;  one  more  concentrated,  ten  times.  The  urine  so  diluted 
is  poured  into  a  burette  and  allowed  to  flow  into  the  boiling  copper- 
sulphate  and  Eochelle-salt  solution  until  the  copper  oxide  is  com- 
pletely reduced.  This  has  taken  place  when,  immediately  after 
boiling,  the  blue  color  of  the  solution  disappears.  It  is  very 
difficult  and  requires  some  practice  to  exactly  determine  this  point, 
especially  when  the  copper  suboxide  settles  with  difficulty.  To 
determine  whether  the  color  has  disappeared,  allow  the  copper  sub- 
oxide to  settle  a  little  below  the  meniscus  formed  by  the  surface  of 
the  liquid.  If  this  layer  is  not  blue,  the  operation  is  repeated, 
adding  0.1  c.  c.  less  of  urine;  and  if,  after  the  copper  suboxide  has 
settled,  the  liquid  has  a  blue  color,  the  titration  may  be  considered 
as  completed.  Because  of  the  difficulty  in  obtaining  this  point 
exactly  another  end-reaction  has  been  suggested.  This  consists  in 
filtering  immediately  after  boiling  a  small  portion  of  the  treated 
urine  through  a  small  filter  into  a  test-tube  which  contains  a  little 

1  Pflilger's  Arch.,  Bdd.  16  u.  23;  Journal  f.  prakt.  Cliem.  (N.  F.),  Bd.  26. 


QUANTITATIVE  ESTIMATION  OF  SUGAR.  551 

acetic  acid  and  a  few  drops  of  potassium-ferrocyanide  solution  and 
water.  The  smallest  quantity  of  copper  is  shown  by  a  red  colora- 
tion. If  the  operation  is  quickly  conducted  so  that  no  oxidation  of 
the  suboxide  into  oxide  takes  place,  this  end-reaction  is  of  value  for 
urines  which  are  rich  in  sugar  and  poor  in  urea  and  which  have 
been  strongly  diluted  with  water.  In  urines  poor  in  sugar  which 
contain  the  normal  amount  of  urea  and  which  have  not  been 
strongly  dilated,  a  rather  abundant  formation  of  ammonia  from  the 
urea  may  take  place  on  boiling  the  alkaline  liquid.  This  ammonia 
dissolves  the  suboxide  in  part,  which  easily  passes  into  oxide 
thereby,  and  besides  this  the  dissolved  suboxide  gives  a  red  color 
with  potassium  ferrocyaiiide.  In  just  those  cases  in  which  the  titra- 
tion is  most  dilficult  this  end-reaction  is  the  least  reliable.  Practice 
also  renders  it  unnecessary,  and  it  is  therefore  best  to  depend  simply 
upon  the  appearance  of  the  liquid. 

To  facilitate  the  settling  of  the  copper  suboxide  and  thereby 
clearing  the  liquid,  MuNK  '  has  lately  suggested  the  addition  of  a 
little  calcium-chloride  solution  and  boiling  again.  A  precipitate  of 
calcium  tartrate  is  produced  which  carries  down  the  suspended 
copper  suboxide  with  it,  and  the  color  of  the  liquid  can  then  be 
better  seen.  This  artifice  succeeds  in  many  cases,  but  unfortunately 
there  are  urines  in  which  the  titration  with  Fehling's  solution  in 
no  way  gives  exact  results.  In  those  cases  in  which  only  small 
quantities  of  sugar  exist  in  a  urine  rich  in  physiological  constituents 
it  is  best  to  dissolve  a  very  exactly  weighed  quantity  of  pure 
dextrose  or  dextrose-sodium  chloride  in  the  urine.  The  urine  can 
now  be  strongly  diluted  with  water  and  the  titration  is  successful. 
The  difference  between  the  added  sugar  and  that  found  by  titra- 
tion gives  the  reducing  power  of  the  original  urine  calculated  as 
dextrose. 

The  necessary  conditions  for  the  success  of  the  titration  under 
all  circumstances  are,  according  to  Soxhlet,''  the  following:  The 
copper-sulphate  and  Rochelle-salt  solution  must,  as  above,  be 
diluted  to  50  c.  c.  with  water;  the  urine  must  only  contain  between 
0.5%  and  1;^  sugar,  and  the  total  quantity  of  urine  required  for  the 
reduction  must  be  added  to  the  titration  liquid  at  once  and  boiled 
with  it.  From  this  last  condition  it  follows  that  the  titration  is 
dependent  upon  minute  details,  and  several  titrations  are  required 
for  each  determination. 

It  is  best  to  give  here  an  example  of  the  titration.  The  proper 
amount  of  copper-sulphate  and  Rochelle-salt  solution  and  water 
(total  volume  =  50  c.c.)  is  heated  to  boiling  in  a  flask;  the  color 
must  remain  blue.  The  urine  diluted  five  times  is  now  added  to 
the  boiling-hot  liquid,  1  c.  c.  at  a  time;  after  each  addition  of- urine 
boil  for  a  few  seconds,  and  look  for  the  appearance  of  the  end- 
reaction.     If  you  find,  for  example,  that  3  c.  c.  is  too  little,  but 

'  Vircbow's  Arch.,  Bd.  105. 

«  Journal  f.  prakt.  Cbem.  (N.  F.),  Bd.  21. 


552  TEE   URINE. 

that  4  c.  c.  is  too  much  (the  liquid  becoming  yellowish),  then  the 
urine  has  not  been  sufficiently  dilated,  for  it  should  require  between 

5  and  10  c.  c.  of  the  urine  to  produce  the  complete  reduction.  The 
urine  is   now  diluted  ten  times,   and   it  should  require    between 

6  and  8  c.  c.  for  a  total  reduction.  Now  prepare  four  new  tests, 
which  are  boiled  simultaneously  to  save  time,  and  add  at  one  time 
respectively  6,  6-g^,  7,  and  7^  c.  c.  of  urine.  If  it  is  found  that 
between  G-g-  and  7  c.  c.  are  necessary  to  produce  the  end-reaction, 
then  make  four  other  tests,  to  which  add  respectively  6.6,  6.7,  6.8, 
and  6.9  c.  c.  of  urine.  If  in  this  case  the  liquid  is  still  somewhat 
bluish  with  6.7  c.  c.  and  completely  decolorized  with  6.8  c.  c,  we 
then  consider  the  average  figure  6.75  c.  c.  as  correct. 

The  calculation  is  simple.  The  6.75  c.  c.  used  contain  0.05 
grm.   sugar,  and  the  percentage  of  sugar  in   the  dilute  urine  is 

5 

therefore  (6.75  :  0.05  =  100  :  x)  =  -—-  =  0.74.     But  as  the  urine 

D.75 

■was  diluted  with  ten  times  its  volume  of  water,  the  undiluted  urine 

5  X  10 
contained  -^-jrc  -  =  7.4^.     The  general  formula  on  using  10  c.  c. 

5  X  w 
€opper-sulphate  solution  is  therefore  — r — ,  in  which  7i  represents 

fC 

the  number  of  times  the  urine  has  been  diluted  and  k  the  number 
(Of  c.  c.  used  for  the  titration  of  the  diluted  urine. 

The  TiTEATioisr  accordistg  to  KiSTAPP  depends  on  the  fact  that 
mercuric  cyanide  is  reduced  into  metallic  mercury  by  grape-sugar. 
The  titration  liquid  should  contain  10  grms.  chemically  pure  dry 
mercuric  cyanide  and  100  c.  c.  caustic-soda  solution  of  a  specific 
.gravity  of  1.145  per  litre.  When  the  titration  is  performed  as 
described  below  (according  to  Worm  Muller  and  Otto),  20  c.  c.  of 
this  solution  should  correspond  to  exactly  0.05  grm.  grape-sugar. 
If  we  proceed  in  other  ways,  the  value  of  the  solution  is  difEerent. 

Also  in  this  titration  the  quantity  of  sugar  in  the  urine  should 
be  between  ^<fo  and  1^,  and  here  also  the  extent  of  dilution  neces- 
sary must  be  determined  by  a  preliminary  test.  To  determine  the 
-end-reaction  as  described  below,  the  test  for  excess  of  mercury  is 
made  with  sulphuretted  hydrogen. 

In  performing  the  titration  allow  20  c.  c.  of  Knapp's  solution 
to  flow  into  a  flask  and  dilute  with  80  c.  c.  water,  or,  when  you  have 
reason  to  think  that  the  urine  contains  less  than  0.5^  of  sugar, 
only  with  40-60  c.  c.  After  this  heat  to  boiling  and  allow  the 
(dilute  urine  to  flow  gradually  into  the  hot  solution,  at  first  2  c.  c, 
then  1  c.  c,  then  0.5  c.  c,  then  0.2  c.  c,  and  lastly  0.1  c.  c. 
After  each  addition  let  it  boil  i  minute.  When  the  end-reaction  is 
approaching,  the  liquid  begins  to  clarify  and  the  mercury  separates 
with  the  phosphates.  The  end-reaction  is  determined  by  taking  a 
drop  of  the  upper  layer  of  the  liquid  into  a  capillary  tube  and  then 
blowing  it  out  on  pure  white  filter-paper.  The  moist  spot  is  first 
held  over  a  bottle  containing  fuming  hydrochloric  acid  and  then 


QUANTITATIVE  ESTIMATION   OF  SUGAR.  553 

over  strong  sulphuretted  hydrogen.  The  presence  of  a  minimum 
quantity  of  mercury-salt  in  the  liquid  is  shown  by  the  spot  becom- 
ing yellowish,  which  is  seen  best  when  it  is  compared  with  a  second 
spot  which  has  not  been  exposed  to  sulphuretted  hydrogen.  The 
end-reaction  is  still  clearer  when  a  small  part  of  the  liquid  is 
filtered,  acidified  with  acetic  acid,  and  tested  with  sulphuretted 
hydrogen  (Otto').  The  calculations  are  just  as  simple  as  for  the 
previous  method. 

This  titration,  unlike  the  previous  one,  may  be  performed  not 
only  in  daylight,  but  also  in  artificial  light.  Knapp's  method  has 
the  following  advantages  over  Fehlixg's  method:  It  is  applicable 
even  when  the  quantity  of  sugar  in  the  urine  is  very  small  and  the 
quantity  of  the  other  urinary  constituents  is  normal.  It  is  more 
easily  performed,  and  the  titration  liquids  may  be  kept  without 
decomposing  for  a  long  time  (Worm  Muller  and  his  pupils'). 
The  views  of  different  investigators  on  the  value  of  this  titration 
method  are  still  somewhat  contradictory. 

Estimation  of  the  Quantity  of  Sugar  by  Fermentation. 
This  may  be  done  in  various  ways;  the  simplest,  and  one  at  the  same 
time  sufficiently  exact  for  ordinary  cases,  is  Roberts'  '  method. 
This  method  consists  in  determining  the  specific  gravity  of  the 
urine  before  and  after  fermentation.  In  the  fermentation  of  sugar, 
carbon  dioxide  and  alcohol  are  formed  as  chief  products  and  the 
specific  gravity  is  lowered,  partly  on  account  of  the  disappearance 
of  the  sugar  and  partly  on  account  of  the  production  of  alcohol. 
Egberts  found  that  a  decrease  of  0.001  in  the  specific  gravity 
corresponded  to  0.23,^  sugar,  and  this  has  been  substantiated  since 
by  several  other  investigators  (Worm  Muller'  and  others).  If 
the  urine,  for  example,  has  a  specific  gravity  of  1.030  before 
fermentation  and  1.008  after,  then  the  quantity  of  sugar  contained 
therein  was  22  X  0.23  =  5.06^. 

In  performing  this  test  the  specific  gravity  must  be  taken  at  the 
same  temperatiire  before  and  after  the  fermentation.  The  urint; 
must  be  faintly  acid,  and  when  necessary  jl  should  be  acidified  with 
a  little  tartaric-acid  solution.  The  activity  of  the  yeast  must,  when 
necessary,  be  controlled  by  a  special  test.  Place  200  c.  c.  of  the 
urine  in  a  400-c.  c.  flask  and  add  a  piece  of  compressed  yeast  the 
size  of  a  pea,  and  subdivide  the  yeast  through  the  liquid  by  shaking, 
close  the  flask  with  a  stopper  provided  with  a  finely  drawn-out 
glass  tube,  and  allow  the  test  to  stand  at  the  temperature  of  the 
room  or,  still  better,  at  +  20-25°  C.  After  21-48  hours  the 
fermentation  is  ordinarily  ended,  but  this  must  be  verified  by  the 
bismuth  test.     After  complete  fermentation  filter  through  a  dry 

'  Journal  f.  prakt.  Chem.,  Bd.  26. 

«PflUger'3  Arch.,  Bdd.  16  u.  23. 

»  Edinburgh  Med.  Journal.  Oct.  1861;  The  Lancet,  Vol.  1,  1862. 

'"-  Pfluger's  Arch.,  Bdd.  33  u.  37. 


554  THE  URINE. 

filter,  bring  the  filtrate  to  tlie  proper  temperature,  and  determine 
the  specific  gravity. 

If  the  specific  gravity  be  determined  with  a  good  pyknometer 
supplied  with  a  thermometer  and  an  expansion-tube,  this  method, 
whea  the  quantity  of  sugar  is  not  less  than  4-5  p.  m.,  gives, 
according  to  Wokm  Muller,  very  exact  results,  but  this  has  been 
disputed  by  Budde.'  For  the  physician  the  method  in  this  form 
is  not  quite  serviceable.  Even  when  the  specific  gravity  is  deter- 
mined by  a  delicate  urinometer  which  can  give  the  density  to  the 
fourth  decimal,  we  do  not  obtain  quite  exact  results,  because  of  the 
principal  errors  of  the  method  (Budde)  ;  but  the  errors  are  usually 
smaller  than  those  which  occur  in  titrations  made  by  unpractised 
hands.  Among  the  methods  proposed  and  closely  tested  for  the 
quantitative  estimation  of  sugar,  we  have  none  which  are  at  the 
same  time  easily  performed  and  which  give  positive  results  in  other 
than  experienced  hands. 

When  the  quantity  of  sugar  is  less  than  5  p.  m.  these  methods 
cannot  be  used.  Such  a  small  quantity  of  sugar  cannot,  as  above 
mentioned,  be  determined  by  titration  directly,  because  the  reduc- 
tion power  of  normal  urine  corresponds  to  4-5  p.  m.  In  such 
cases,  according  to  Worm  Muller,  first  determine  the  reduction 
power  of  the  urine  by  titration  with  Knapp's  solution,  then  ferment 
the  urine  with  the  addition  of  yeast,  and  titrate  again  with 
Knapp's  solution.  The  dift'erence  found  between  the  two  titra- 
tions calculated  as  sugar  gives  the  true  quantity  of  sugar. 

Estimation  of  Sugar  by  Polakization.  In  this  method  the 
urine  must  be  clear,  not  too  deeply  colored,  and,  above  all,  must 
not  contain  any  other  optically  active  substances  besides  glucose. 
]5y  using  a  delicate  instrument  and  with  sufficient  practice  very 
exact  results  can  be  obtained  by  this  method.  For  the  physician, 
Roberts'  fermentation  test,  which  requires  no  expensive  apparatus 
and  no  special  practice,  is  to  be  preferred.  Under  such  circum- 
stances, and  as  the  estimation  by  means  of  polarization  can  be 
performed  with  exactitude  only  by  specially  instructed  chemists,  it 
is  hardly  necessary  to  give  this  method  in  detail,  and  the  reader  is 
referred  to  special  works  for  instructions  in  the  use  of  the  apparatus. 

Levulose.  Lsevogyrate  urines  containing  sugar  have  been  observed  by 
Ventzke,  Zimmek  and  Czapkk,  Seegen,  and  others.*  The  nature  of  the  sub- 
stance causing  this  action  is  diliicult  to  d  scribe  exactly,  but  there  is  hardly 
any  doubt  that  the  urine,  at  least  in  certain  cases,  as  in  those  observed  by  See- 
GKN,  contains  levulose.  The  occurrence  of  laevulose  in  the  urine  from  See- 
GEN's  patient  has  been  made  very  possible  by  KcLZ.^ 

The  presence  of  levulose  in  a  urine  containing  sugar  is  only  probable  when 
the  urine  is  lsevogyrate  or  optically  inactive,  or  when  it  shows  a  reduction 
power  not  corresponding  (less)  to  the  dextrorotary  power,  or  when  it  contains 

1  Ugeskrift  for  Laeger.  (4),  Bd.  9;  Pfliiger's  Arch.,  Bd.  40;  Zeitschr,  f. 
pbysicl.  Chem.,  Bd.  13. 

*  See  Iluppert-Neubauer,  Harnanalyse,  10.  Aufl.,  S.  125. 
3  Zeitschr.  f.  Biologie,  Bd.  27. 


MILK-SUGAR  AND  PENTOSES.  555 

no  other  Igevoegyrate  substance  (/tf-oxybutyric  acid,  conjugated  glycuronic  acids, 
protein  bodies,  or  cystin).  Levulose  ferments  with  yeast  and  yields  the  same 
osazone  as  glucose. 

Laiose  is  a  substance  found  by  Leo  '  in  diabetic  urines  in  certain  cases, 
and  which  Leo  considers  as  a  sugar.  It  is  Isevcegyrate,  amorphous,  and  has 
no  sweet  taste,  but  rather  a  sharp  and  salty  taste.  Laiose  has  a  reducing 
action  on  metallic  oxides,  does  not  ferment,  and  gives  a  noncrystalline,  yellow- 
ish-brown  oil  with  phenylhydrazin.  We  have  no  positive  proof  as  yet  that 
this  substance  is  a  sugar. 

Milk-sugar.  The  appearance  of  milk-sagar  in  the  urine  with 
engorgement  of  milk  has  been  made  known  especially  by  the  inves- 
tigations of  De  Sinety  and  F.  Hofmeister.^  After  taking  large 
quantities  of  milk-sngar  some  lactose  may  be  foand  in  the  urine 
(see  Chapter  IX  on  absorption). 

The  positive  detection  of  milk-sngar  in  the  urine  is  difficult, 
because  this  sngar  is,  like  glucose,  dextrogyrate  and  also  gives  the 
usual  reduction  tests.  If  urine  contains  a  dextrogyrate,  non- 
fermentable  sugar  which  reduces  bismuth  solutions,  then  it  is  very 
probable  that  it  contains  milk-sugar.  It  must  be  remarked  that 
the  fermentation  test  for  milk-sugar  is,  according  to  the  experience 
of  Lrss  and  Yoit,'  best  performed  by  using  pure  cultivated  yeast 
(saccharomycesapiculntus).  This  yeast  only  ferments  the  glucose, 
while  it  does  not  decompose  the  milk-sugar.  The  most  positive 
means  for  tlie  detection  of  lactose  is  to  isolate  the  sugar  from  the 
urine.  This  may  be  done  by  the  following  method,  suggested  by 
F.  Hofmeister:  * 

Precipitate  the  urine  with  sugar  of  lead,  filter,  wash  with  water,  unite  the 
filtrate  and  wash-water,  and  precipitate  with  ammonia.  The  liquid  filtered 
from  the  precipitate  is  again  precipitated  by  sugar  of  lead  and  ammonia  until 
the  last  filtrate  is  optically  inactive.  The  several  precipitates  with  the  excep- 
tion of  tlie  first,  which  contains  no  sugar,  are  united  and  washed  with  water. 
The  washed  precipitate  is  decomposed  \\\  tbc  cold  with  sulphuretted  hydrogen 
and  filtered.  The  excess  of  sulpiiuretted  liydror^en  is  driven  off  by  a  current 
of  air;  the  acids  set  free  are  removed  by  shaking  with  silver  oxide.  Now  filter, 
remove  the  dissolved  silver  by  sulphurctti  d  hydrogen,  treat  with  ba  ium  car- 
bontite  to  unite  with  any  free  acetic  acid  present,  and  concentrate.  Before  the 
evaporated  residue  is  syrupy  it  is  treated  with  90j?  iilcohol  until  a  flocculent 
precipitate  is  formed  which  settles  quickly.  The  filtrate  from  this  when 
placed  in  a  desiccator  deposits  crystals  of  milk-sug:ir,  which  are  purified  by 
recrystallization,  decolorizing  with  animal  charcoal  and  boiling  with  GO-70^ 
alco  lol. 

Pentoses.  Salkowski  and  Jastrowitz''  found  in  the  urine  of  persons 
addicted  to  the  morphin  habit  a  variety  of  sitgar  which  was  a  pentose  and 

>  Virchow's  Arch.,  Bd.  107. 

*  Zeitschr.  f.  physiol.  C'hem.  Bd.  \,  S.  101,  which  also  contains  the  perti- 
nent literature. 

^  Carl  Voit,  tiber  die  Qlycogenbildung  nach  Aufnahme  verschiedener  Zuck- 
erarten,  Zeitschr.  f.  Biologic,  Bd.  28. 

*L.  c. 

»  Centralbl.  f.  d.  med.  Wissensch.,  1893,  Nos.  19  and  33. 


556  THE   URINE. 

yielded  an  osazone  which  melted  at  159°  C.  Salkowski  '  has  observed  two  new 
cases  of  pentosuria.  The  pentose  in  the  urine  seemed  to  be  identical  with  tl^e 
pentose  obtained  by  Hammarsten  on  the  cleavage  of  a  pancreas  proteid.  E. 
KcLZ  and  J.  Vogel^  have  detected  pentoses  in  the  urine  of  diabetics,  as  well 
as  in  tliat  of  dogs  with  pancreas  or  phlorhizin  diabetes.  Concentrated  hydro- 
chloric acid  saturated  with  phloroglucin  may  be  used  in  detecting  pentoses. 
Add  \  volume  of  the  urine  to  be  tested  to  the  acid  and  warm.  In  the  presence 
of  pentoses  the  red  coloration  mentioned  on  page  65  appears.  This  test  is  not 
conclusive,  as  glycuronic  acid  gives  the  same  reaction;  further  investigation  is 
therefore  necessary. 

IifOSiT  occnrs  only  rarely,  and  in  but  small  quantities,  in  the 
urine  in  albuminuria  and  in  diabetes  mellitus.  After  excessive 
drinking  of  water  inosit  is  found  in  the  urine.  According  to 
Hoppe-Seyler'  traces  of  inosib  occur  in  all  normal  urines. 

In  detecting  inosit  the  proteid  is  first  removed  from  the  urine.  Then  con- 
centrate the  urine  on  the  water-bath  to  \  and  precipitate  with  sugar  of  lead. 
The  filtrate  is  warmed  and  treated  with  basic  lead  acetate  as  long  as  a  precipi- 
tate is  formed.  The  precipitate  formed  after  24  hours  is  washed  with  water, 
suspended  in  water,  and  decomposed  with  sulphuretted  hydrogen.  A  little  uric 
acid  may  separate  from  the  filtrate  after  a  short  time.  The  liquid  is  filtered, 
concentrated  to  a  syrupy  consistency,  and  treated  while  boiling  with  3-4  vols, 
alcohol.  The  precipitate  is  quickly  separated.  After  the  addition  of  ether  to 
the  cooled  filtrate,  crystals  separate  after  a  time,  and  these  are  purified  by  de- 
colorization  and  recrystallization.  With  these  crystals  perform  the  tests  men- 
tioned on  page  370. 

Acetone  and  Diacetic  Acid.  These  bodies,  the  occurrence  in  the 
urine  and  formation  in  the  organism  of  which  have  been  the  subject 
of  numerous  investigations,  especially  by  v.  Jaksch,*  were  first 
observed  in  urine  in  diabetes  mellitus  (Peters,  Kaulich, 
V.  Jaksch,  Gerhardt).  Acetone  may  give  the  diabetic  urine 
as  well  as  the  expired  air  the  odor  of  apples  or  other  fruit. 
According  to  v.  Jaksch  and  others  acetone  is  a  normal  urinary 
constituent,  though  it  may  only  occur  in  very  small  amounts 
(0.01  grm.  in  the  24  hours). 

Acetone  may,  as  found  by  v.  Jaksch,  be  a  by-product  in  lactic- 
acid  fermentation,  and  this  origin  for  the  traces  of  acetone  eliminated 
by  the  normal  urine  requires  further  proof.  There  is  no  doubt  that 
the  appearance  of  acetone  as  well  as  diacetic  acid  is  essentially 
caused  by  an  increased  destruction  of  proteid.  This  follows  from 
the  very  marked  increase  in  the  elimination  of  acetone  and  diacetic 

'  Berliner  klin.  Wochenschr.,  1895. 

2  Zeitschr.  f.  Biologie,  Bd.  32. 

3  Handbuch  d.  physiol.  u.  pathol.  chem.  Analyse,  6.  AuiL,  S.  196. 

•*  In  regard  to  the  extensive  literature  on  acetone  and  diacetic  acid  we  refer 
the  reader  to  Huppert-Neubauer,  Harnanalyse,  10.  Aufl.,  and  v.  Noorden's 
Lehrb.  d.  Pathol,  des  Stoffwechsels,   Berlin,  1893. 


ACETONE  AND  DI ACETIC  ACID.  bbl 

acid  during  inanition  (v.  Jaksck,'  I'r.  Muller').  This  is  also  in 
accord  with  the  observations  of  Wright'  that  in  diabetes  no  rela- 
tionship exists  between  the  elimination  of  acetone  and  sugar,  while 
there  is  a  relationship  between  the  elimination  of  acetone  and 
nitrogen;  thus  on  the  days  when  most  nitrogen  is  eliminated  we 
find  the  highest  results  for  the  acetone,  and  vice  versa.  Abundant 
proteid  lood  also  increases  the  elimination  of  acetone,  according  to 
HoxiuMA:Nrx "  and  v.  Noordex,'  apparently  in  the  case  where  with 
a  one-sided  proteid  food  an  insufficient  supply  of  calories  takes 
place,  which  leads  to  a  reduction  of  the  body-proteid.  According 
to  this  view,  which  requires  further  proof,  the  extent  of  the  elimi- 
nation of  acetone  and  diacetic  acid  is  not  dependent  upon  the  extent 
of  the  metabolism  of  proteid,  but  upon  the  quantity  of  destroyed 
body-proteid. 

According  to  this  view  it  is  also  clear  that  an  abundant  elimina- 
tion of  acetone  and  diacetic  acid  is  observed,  especially  in  such 
diseases  in  which  an  abundant  destruction  of  body-proteid  takes 
place,  such  as  fevers,  diabetes,  disturbed  digestion,  mental  debility 
with  abstinence,  cachexia,  etc.  It  has  not  been  proven  how  far  the 
acetonuria  experimentally  produced  by  Lustig  °  by  lesion  of  the 
sinus  fovea  rhomboidalis  or  by  excision  of  the  solar  plexus  is  caused 
by  the  generally  disturbed  condition  of  the  animal  or  by  other  cir- 
cumstances. 

Diacetic  acid  has  not  been  observed  as  a  physiological  constituent 
of  the  urine.  It  occurs  in  the  urine  chiefly  under  the  same  condi- 
tions as  acetone;  still  we  have  cases  in  which  only  acetone  and  no 
diacetic  acid  appears.  Like  acetone  the  diacetic  acid  occurs  often 
in  children,  especially  in  high  fevers,  acute  exanthema,  etc.  Dia- 
cetic acid  decomposes  readily  into  acetone.  According  to  Araki  ^ 
it  is  probably  produced  as  an  intermediate  product  in  the  oxidation 
of  yS-oxybutyric  acid  in  the  organism.     The  three  bodies  appearing 

'  Ueber  Acetonurie  and  Diaceturie.     Berlin,  1885. 

'  Bericlit  iiber  die  Ergebnisse  des  an  Cetti  ausgef lihrten  Hungerversuclies. 
Berlin,  klin.  Wocbenschr.,  1887. 

»See  Maly's  Jabresber.,  Bd.  21,  S.  404. 

•*  Zur  Enstebung  des  Acetons.  Diss.  Breslau,  1886.  Cited  from  v.  Noorden, 
Lehrb.,  S.  177. 

*L.  c  ,  S.  78. 

«  Centralbl.  f.  Physiol.,  Bd.  6. 

'Zeitscbr.  f.  pbysiol.  Cbem.,  Bd.  18. 


558  TEE   URINE. 

in  the  urine,  acetone,  diacetic  acid,  and  oxybutyric  acid,  stand  in 
close  relationship  to  each  other. 

Acetone,  dimethyl  ketone,  Cgll^O  or  C0.(CH3)„  is  a  thin  water- 
clear  liquid  boiling  at  56.5°  C.  and  with  a  pleasant  odor  of  fruit. 
It  is  lighter  than  water,  with  which  it  mixes  in  all  proportions,  also 
with  alcohol  and  ether.  The  most  important  reactions  for  acetone 
are  the  following: 

Lieben's  '  Iodoform  Test.  When  a  watery  solution  of  acetone 
is  treated  with  alkali  and  then  with  some  iodine-potassiam-iodide 
solution  and  gently  warmed  a  yellow  precipitate  of  iodoform  is 
formed,  which  is  known  by  its  odor  and  by  the  appearance  of  the 
crystals  (six-sided  plates  or  stars)  under  the  microscope.  This 
reaction  is  very  delicate,  but  it  is  not  characteristic  of  acetone. 
Guj^ning's '^  modification  of  the  iodoform  test  consists  in  using  an 
alcoholic  solution  of  iodine  and  ammonia  instead  of  the  iodine  dis- 
sols^ed  in  potassium  iodide  and  alkali  hydrate.  In  this  case,  besides 
iodoform,  a  black  precipitate  of  iodide  of  nitrogen  is  formed,  but 
this  gradually  disappears  on  standing,  leaving  the  iodoform  visible. 
This  modification  has  the  advantage  that  it  does  not  give  any 
iodoform  with  alcohol.  On  the  other  hand,  it  is  not  quite  so 
delicate,  but  still  it  detects  0.01  milligramme  acetone  in  1  c.  c. 

Reynold's  '  mercuric-oxide  test  is  based  on  the  power  of  acetone 
to  dissolve  freshly  precipitated  HgO.  A  mercuric-chloride  solution 
is  precipitated  by  alcoholic  caustic  potash.  To  this  add  the  liquid 
to  be  tested  for  acetone,  shake  well  and  filter.  In  the  presence  of 
acetone  the  filtrate  contains  mercury,  which  may  be  detected  by 
ammonium  sulphide.  This  test  has  about  the  same  delicacy  as 
Gunnijstg's  test. 

Legal's'  Sodium-nitroprusside  Test.  If  an  acetone  solution 
is  treated  with  a  few  drops  of  a  freshly  prepared  sodium-nitro- 
prusside solution  and  then  with  caustic-potash  or  soda  solution,  the 
liquid  is  colored  ruby-red.  Creatinin  gives  the  same  color;  but  if 
we  saturate  with  acetic  acid,  the  color  becomes  carmine  or  purplish 
red  in  the  presence  of  acetone,  but  yellow  and  then  gradually  green 
and  blue  in  the  presence  of  creatinin.  If  we  use  ammonia  instead 
of  the  caustic  alkali  (Le  Nobel),  the  reaction   takes  place  with 

'  Annal.  d.  Chem.  u.  pliarm.,  Suppl.  Bd.  7. 

*  Gunning,  by  Bardy,  Journ.  de  pbarni.  et  chim.  (5),  Tome  4. 

^  Cited  from  Huppert-Neubauer,  Harnanalyse,  10.  Aufl.,  S.  60. 

*  Breslauer  arztl.  Zeitschr. .  1883. 


BI ACETIC  ACID.  559 

acetone,  but  not  with  creatinin."     Legal's  test  indicates  even  0,1 
milligrm.  acetone. 

Penzoldt's  '  indigo  test  depends  on  the  fact  that  orthonitro- 
benzaldehyde  in  alkaline  solution  with  acetone  yields  indigo.  A 
warm  saturated  and  then  cooled  solution  of  the  aldehyde  is  treated 
with  the  liquid  to  be  tested  for  acetone  and  then  with  caustic  soda. 
In  the  presence  of  acetone  the  liquid  first  becomes  yellow,  then 
green,  and  lastly  indigo  separates;  and  this  may  be  dissolved  with 
a  blue  color  by  shaking  with  chloroform.  1.6  milligrms.  acetone 
can  be  detected  by  this  test. 

Malerba  ^  uses  a  solution  of  dimetbylparaphenylendiamin  as  a  reagpnt  for 
acetone.  It  gives  a  red  liquid  which  has  an  absorption-spectrum  very  similar 
to  oxj'haemoglobin. 

Diaceticacid,  oraceto-aceticacid,  C^HgO^or  C^HjO.CHj.COOH. 
This  acid  is  a  colorless,  strongly  acid  liquid  which  mixes  with 
water,  alcohol,  and  ether  in  all  proportions.  On  heating  to  boiling 
with  water,  and  especially  with  acids,  this  acid  decomposes  into 
carbon  dioxide  and  acetone,  and  therefore  gives  the  above-mentioued 
reactions  for  acetone.  It  differs  from  acetone  in  that  it  gives  a 
violet-red  or  brownish-red  color  with  a  dilute  ferric-chloride  solu- 
tion. This  color  decreases  even  at  the  ordinary  temperature  within 
24  hours,  and  more  quickly  on  boiling.  It  differs  in  this  fiom 
phenol,  salicylic  acid,  acetic  acid,  or  sulphocyanides. 

Detection  of  Acetone  and  Diacetic  Acid  in  the  urine.  Before 
testing  for  acetone  test  for  diacetic  acid,  and  as  this  acid  gradually 
decomposes  on  allowing  the  urine  to  stand,  the  urine  must  be  as 
fresh  as  possible.  In  the  presence  of  diacetic  acid  the  urine  gives 
the  so-called  Gerhardt's  reaction,  showing  a  wiue-red  color  on  the 
addition  of  a  dilute,  not  too  acid,  ferric-chloride  solution.  Treat 
10-50  c.  c.  of  the  urine  with  ferric  chloride  as  long  as  it  gives  a 
precipitate,  filter  the  precipitate  of  ferric  phosphate,  and  add  some 
more  ferric  chloride  to  the  filtrate.  In  the  presence  of  the  acid  a 
claret-red  color  is  produced.  After  this  heat  a  second,  similar 
portion  of  the  faintly  acid  urine  to  boiling,  and  repeat  the  test  on 
cooling,  which  should  now  give  negative  results.  A  third  portion 
of  urine  is  acidified  with  sulphuric  acid  and  shaken  with  ether 
(which  takes  up  the  acid).  Now  shake  the  removed  ether  with  a 
very  dilute  watery  solution  of  ferric  chloride,  and  the  watery  layer 
becomes  violet-red  or  claret-red.     The  color  disappears  on  warming. 

'  According  to  the  author  this  statement  is  not  correct. 

'  Arch.  f.  klin.  Med.,  Bd.  34. 

'  Atti  della  R,  Academ.  med,   chirurg.    di  Napoli,  Anno  48,  Nuova  Serie, 


560  TEE   URINE. 

K.  Morner'  suggests  that  in  testing  for  diacetic  acid  in  the 
urine  the  urine  be  treated  with  a  little  KI  and  Fe^Cl^  in  excess 
and  heated.  In  the  presence  of  diacetic  acid  ver}^  irritating  vapors 
of  iodoacetone  (?)  are  developed. 

In  the  absence  of  diacetic  acid  the  acetone  may  be  tested  for 
directly.  This  may  be  done  directly  on  the  urine  by  Pejstzoldt's 
test.  This  test,  which  is  only  approximate,  is  only  of  value  when 
the  urine  contains  a  considerable  amount  of  acetone.  For  a  more 
jiccurate  test  we  distil  at  least  250  c.  c.  of  the  urine  faintly  acidified 
with  sulphuric  acid,  care  being  taken  to  have  a  good  condensation. 
Most  of  the  acetone  is  contained  in  the  first  10-30  c.  c.  of  the  dis- 
tillate. This  distillate  is  tested  for  acetone  by  the  above  tests.  In 
testing  for  acetone  in  the  simultaneous  presence  of  diacetic  acid, 
first  make  the  urine  faintly  alkaline,  and  shake  it  carefully  with 
ether  free  from  alcohol  and  acetone  in  a  separatory  funnel.  The 
removed  ether  is  then  shaken  with  water,  which  takes  up  the 
acetone,  and  then  the  watery  liquid  is  tested. 

TJie  quautiiative  estimation  of  acetone  in  the  urine  is  done  by 
converting  it  first  into  iodoform.  The  urine  is  acidified  with 
acetic  acid  (according  to  Huppert,  1-2  c.  c.  50^  acetic  acid  for 
every  100  c.  c.  urine)  and  distilled.  The  iodoform  formed  is  deter- 
mined in  the  distillate  either  gravimetrically  according  to  Kramer 
or  colorimetrically,  according  to  v.  Ja.ksch.  It  is  best  to  proceed 
according  to  the  method  as  suggested  by  Messikger  and  Hup- 
pert.'' They  determine  the  quantity  of  acetone  by  determining  the 
quantity  of  iodine  necessary  in  the  formation  of  iodoform  by 
titration.  In  regard  to  this  method  and  its  execution  we  refer  the 
reader  to  Huppert-Neubaubr.' 

/i-Oxybutyric  Acid,  C,H,03  or  CH3.CH(0H).CH,C00n.     The 

appearance  of  this  acid  in  the  urine  was  first  positively  shown  by 
Minkowski,"  Kulz  '  and  Stadelmank.'  It  occurs  especially  in 
difficult  cases  of  diabetes,  but  it  has  also  been  observed  in  scarlet 
fever  and  in  measles  (Kulz),  in  scurvy  (Minkowski),  and  in  dis- 
eases of  the  brain  with  abstinence  (Kulz).  yS-oxybutyric  acid  is 
undoubtedly  derived  from  an  abnormal  destruction  of  body-proteid, 
and  it  therefore  occurs  in  the  urine  in  inanition,  cachexia,  etc. 
/?-oxybutyric  acid  is  accompanied  by  diacetic  acid  in  the  urine, 

'  Skan.  Arch.  f.  Physiol.,  Bd.  5. 

*  Huppert-Neubauer,  Harnanalyse,  10.  Aufl. ,  8.  760,  vehich  also  contains 
the  description  of  other  methods  and  summary  of  the  literature. 

3L.  c,  10.  Aufl. 

*  Arch,  f.  exp.  Path.  u.  Pharm.,  Bd.  18  u.  19. 

*  Zeitschr.  f.  Biologie,  Bdd.  20  u.  23. 

«  Arch.  f.  exp.  Path.  u.  Pharm,,  Bd.  17. 


P-0XYBUT7BIC  ACID.  561 

while  on  the  other  hand  the  last-mentioned  acid  occurs  in  the  urine 
without  the  first. 

yS-oxybutyric  acid  forms  an  odorless  syrup  which  mixes  readily 
with  water,  alcohol,  and  ether.  This  acid  is  optically  active  and 
indeed  Isevogyrate,  and  it  therefore  interferes  with  the  estimation 
of  sugar  in  the  urine  by  means  of  polarization.  It  is  not  precipi- 
tated either  by  basic  lead  acetate  or  by  ammoniacal  basic  lead 
acetate.  On  boiling  with  water,  especially  in  the  presence  of  a 
miueral  acid,  this  acid  decomposes  into  (T-crotonic  acid,  which 
melts  at  71-72°  C,  and  water:  CH,.CH(OH).CH,.C00H  =  H,0 
-|- CHj.CHiCH.COOH.  It  yields  acetone  on  oxidation  with  a 
chromic-acid  mixture. 

Detection  of  (d-Oxybutyric  Acid  in  the  urine.  If  a  urine  is  still 
Isevogyrate  after  fermentation  with  yeast,  the  presence  of  oxy- 
butyric  acid  is  probable.  A  further  test  may  be  made,  according 
to  KiJLZ,  by  evaporatingthe  fermented  urine  to  a  syrup,  and,  after 
the  addition  of  an  equal  volume  of  concentrated  sulphuric  acid, 
distilling  directly  without  cooling.  «-crotonic  acid  is  produced 
which  distils  over,  and,  after  collecting  in  a  test-tube,  crystals, 
which  melt  at  -|-  72°  C,  separate  on  strongly  cooling.  If  no- 
crystals  are  obtained,  then  shake  the  distillate  with  ether,  and  test 
the  melting-point  of  the  residue  obtained  after  evaporating  the 
ether  which  has  been  washed  with  the  water.  According  to 
Minkowski  the  acid  may  be  isolated  as  a  silver-salt.' 

Ehiilich's^  Urine  Test.  Mix  250  c.  c.  of  a  solution  which  contains  50  c.  c. 
HCI  and  1  gnn.  sulphanilic  acid  in  one  litre  with  5  c.  c.  of  a  \%  solution  of 
sodium  nitrite  (vvLich  produces  very  little  of  the  active  body,  sulphodiazoben- 
zol)  In  performing  this  test  tn  at  the  urine  with  an  equal  volume  of  this 
mixture  and  then  supt^rsaturate  wiih  ammonia.  Normal  uriue  will  become 
yellow  thereby,  or  orange  after  the  addition  of  ammonia  (aromatic  oxyacids- 
may  sometimes  give  after  a  certain  time  red  azo  bodies  wliich  color  the  "upper 
layer  of  phosphate  sedimen*).  In  pathological  urines  we  sometimes  have  (and 
this  is  the  cuaracteristic  diazo  reaction)  a  primary  yellow  coloration,  with  a 
very  marked  secondary  red  coloration  on  the  addition  of  ammonia,  and  the 
froth  is  also  tinged  with  red.  The  upper  layer  of  the  sediment  becomes  green- 
ish. The  body  which  gives  tins  reaction  is  unknown,  but  it  occurs  especially 
in  the  urine  of  typhoid  patients  (Ehrlich).  Views  are  divided  in  regard  to 
the  significance  of  this  reaction. 

KosENBACn's  urine  test,  which  consists  in  adding  nitric  acid  drop  by  drop 
to  the  boiling-hot  urine  and  obtaining  a  claret-red  coloration  and  a  bluish- 
red  foam  on  shaking,  depends  upon  the  formation  of  indigo  substances, 
especially  indigo  red.'^ 

Fat  in  the  urine.  The  elimination  of  a  urine  which  in  appearance  and  rich- 
ness in  fat  resembles  chyle  is  tailed  chyluria.     It  contains  habitually  proteid„ 

'  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  18,  S.  35;  Zeitschr.  f.  anal.  Chem. . 
Bd.  24,  S.  153. 

*  Zeitschr.  f.  klin.  Med.,  Bd.  5. 

*  See  Rosin,  Viichow's  Arch.,  Bd.  123. 


562  THE   URINE. 

and  often  fibrin.  Cliyluria  occurs  mostly  iu  the  inhabitants  of  the  tropics. 
Lipuria,  or  the  elimination  of  fat  with  the  urine,  may  appear  in  apparently 
healthy  persons,  sometimes  with  and  sometimes  without  albuminuria,  in  preg- 
nancy, and  also  in  certain  diseases,  as  in  diabetes,  poisoning  with  phosphorus, 
and  fatty  degeneration  of  the  kidneys. 

Fat  is  usually  detected  by  the  microscope.  It  may  also  be  dissolved  with 
ether,  and  it  may  always  be  detected  by  evaporating  the  urine  to  dryness  and 
extracting  the  residue  with  ether. 

Cholesterin  is  also  sometimes  found  in  the  urine  in  chyluria  and  in  a  few 
other  cases. 

Leucin  and  Tyeosin.  These  bodies  are  found  in  the  urine, 
especially  in  acute  yellow  atrophy  of  the  liver,  in  acute  phosphorus- 
poisoning,  and  in  difficult  cases  of  typhoid  and  smallpox. 

Detection  of  Leucin  and  Tyrosin.  Tyrosin  occurring  as  sediment  may  be 
identified  by  means  of  the  microscope  ;  but  if  a  positive  proof  is  desired,  a 
recrystallization  of  the  same  from  ammonia  or  ammoniacal  alcohol  is  neces- 
sary. 

I'o  detect  both  these  bodies  when  tliey  occur  in  solution  in  the  urine,  pro- 
ceed in  the  following  manner  :  The  urine  free  from  proteid  is  precipitated  by 
basic  lead  acetate,  the  lead  removed  from  the  filtrate  by  H28,  and  concentrated 
as  much  as  possible.  The  residue  is  extracted  with  a  small  quantity  of  absolute 
alcohol  to  remove  the  nrea.  The  residue  is  then  boiled  with  faintly  ammoniacal 
alcohol,  filtered,  the  filtrate  evaporated  to  a  small  volume  and  allowed  to  crys- 
tallize. If  no  tyrosin  crystals  are  obtained,  then  dilute  with  water,  precipitate 
again  with  basic  lead  acetate,  and  proceed  as  before.  If  tyrosin  crystals  now 
separate,  they  are  filtered,  and  the  filtrate  still  further  concentrated  to  obtain  the 
leucin  crystals. 

Cystin  (C.H^NSOJ^.  This  body  is,  according  to  Baumann,' 
to  be  considered  as  disulphide,      '  ^  yb(   ^, S/    \NH  ' 

of  the  previously  mentioned  cystein,  CjH^JSTSO,  (page  529).    Cystein 

XT  p  s         ,  STT 
itself  is  of-amidothiolactic  acid,  ttV/S\/^qqtt-     Cystin  is  con- 
verted into  cystein  by  nascent  hydrogen  and  is  reconverted  into 
cystin  by  oxidation. 

Baumank  and  Goldmakn''  claim  that  a  substance  similar  to 
cystin  occurs  in  very  small  amounts  in  normal  urine.  This  sub- 
stance occurs  in  large  quantities  in  the  urine  of  dogs  after  poisoning 
with  phosphorus.  Cystin  itself  is  found  with  positiveness,  and  even 
then  very  rarely,  only  in  urinary  calculi  and  in  pathological  urines, 
from  which  it  may  separate  as  a  sediment.  Cystiniiria  occurs 
oftener  in  men  than  in  women,  and  cystin  seems  to  be  an  abnormal 
splitting  product  of  the  proteids.     Baumann  and  v.  Udranszky  * 

'  Zeitschr.  f.  Physiol.  Chem.,  Bd.  8.     In  regard  to  the  literature  on  cystia 
see  Breiizlnger,  ibid.,  Bd.  16,  S.  552. 
"  Zeitschr.  f   physiol.  Chem.,  Bd.  13. 
^  Ibid.,  Bd.  13 


UYSTIN.  563 

iouiid  in  uriue  in  cystinnria  the  two  diamins,  cadaverin  (penta- 
metbylendiamin)  and  putrescin  (tetramethylendiamin),  wliicli  are 
prod  need  in  the  putrefaction  of  proteids.  These  two  diamins  were 
also  found  in  the  contents  of  the  intestine .  in  cystinnria,  while 
under  normal  conditions  they  are  not  present.  The  author 
therefore  considers  that  perhaps  some  connection  exists  between 
the  formation  of  diamins  in  the  intestine,  by  the  peculiar  putrefac- 
tion in  cystinnria,  and  cystinnria  itself.  Cadaverin  has  also  been 
found  in  the  urine  in  cystinnria  by  Stadthagex  and  Brieger.' 
Cystin  has  also  been  found  in  ox-kidneys,  in  horse's  liver 
(Drechsel^),  and  as  traces  in  the  liver  of  a  drunkard.  Kulz  * 
once  observed  the  occurrence  of  cystin  during  the  digestion  of  fibrin 
with  pancreas. 

Cystin  crystallizes  in  thin,  colorless,  six-sided  plates.  It  is  not 
soluble  either  in  water,  alcohol,  etber,  or  acetic  acid,  but  dissolves 
in  mineral  acids  and  oxalic  acid.  It  also  dissolves  in  alkalies  and 
in  ammonia,  but  not  in  ammonium  carbonate.  Cystin  is  optically 
active  and  strongly  laevorotatory.  If  cystin  is  boiled  with  caustic 
alkali  it  decomposes,  yielding  among  other  products  alkali  sulphides, 
which  may  be  detected  by  lead  acetate  or  sodium  nitroprasside. 
On  treating  cystin  with  tin  and  hydrochloric  acid,  only  a  little  sul- 
phuretted hydrogen  is  evolved  and  cystein  is  produced.  On  shaking 
a  solution  of  cystin  in  an  excess  of  caustic  soda  with  benzoyl- 
chloride  a  voluminous  precipitate  of  benzoyl-cystin  is  produced 
(Battmann  and  Goldmaxn').  On  heating  on  platinum  foil, 
cystin  does  not  melt,  but  ignites  and  burns  with  a  bluish-green 
flame  accompanied  by  a  peculiar  sharp  odor.  On  warming  with 
nitric  acid  cystin  dissolves  with  decomposition  and  leaves  a  reddish- 
brown  residue  on  evaporation  which  does  not  give  the  murexid  test. 

Cystein  hydrochloi-ide  gives  a  nearly  insoluble  precipitate  having 
the  composition  2(C3H,NSOJ  +  SHgCl,  with  mercuric  chloride. 
Baumann  and  Borissow  ^  have  based  a  method  for  the  quantitative 
estimation  of  cystin  on  this  behavior.  They  first  reduce  the  cystin 
by  zinc  and  hydrochloric  acid. 

Cystin  is  easily  prepared  from  cystin  calcnli  by  dissolving  them 
in  alkali  carbonate,  precipitating  the  solution  with  acetic  acid,  and 
»  Berl.  klin.  Wocbenschr.,  1889. 
'  Du  Bois-Reyinond's  Arch.,  1891. 
3  Zeits.hr.  f   Biolofrie,  Bd.  27. 
*Zeitscbr   f.  physiol  Chem.,  Bd.  12. 
*lbid.,  Bd.  19,  S.  511. 


564  THE   URINE. 

redissolving  the  precipitate  in  ammonia.  The  cystin  crystallizes  on 
the  spontaneous  evaporation  of  the  ammonia.  The  cystin  dissolved 
in  the  urine  is  detected,  in  the  absence  of  proteid  and  sulphuretted 
hydrogen,  by  boiling  with  alkali  and  testing  with  lead  salt  or  sodium 
nitroprnsside.  To  isolate  cystin  from  the  urine,  acidify  the  urine 
strongly  with  acetic  acid.  The  precipitate  containing  cystin  ia 
collected  after  24  hours  and  digested  with  hydrochloric  acid,  which 
dissolves  the  cystin  and  calcium  oxalate,  leaving  the  uric  acid 
undissolved.  Filter,  supersaturate  the  filtrate  with  ammonium  car- 
bonate, and  treat  the  precipitate  with  ammonia,  which  dissolves  the 
cystin  and  leaves  the  calcium  oxalate.  Filter  again  and  precipitate 
with  acetic  acid.  The  precipitated  cystin  is  identified  by  the 
microscope  and  the  above-mentioned  reactions.  Cystin  as  a  sedi- 
ment is  identified  by  the  microscope.  It  must  be  purified  by 
dissolving  in  ammonia  and  precipitating  with  acetic  acid  and  then 
tested.  Traces  of  dissolved  cystin  may  be  detected  by  the  produc- 
tion of  benzoyl-cystin,  according  to  Baumann  and  Goldman^n. 

VII.  Urinary  Sediments  and  Calculi. 

Urinary  sediment  is  the  more  or  less  abundant  deposit  which  is' 
found  in  the  urine  after  standing.  This  deposit  may  consist  partly 
of  organized  and  partly  of  non-organized  constituents.  The  first, 
consisting  of  cells  of  various  kinds,  yeast-fungus,  bacteria,  sperma- 
tozoa, casts,  etc.,  must  be  investigated  by  means  of  the  microscope,, 
and  the  following  only  applies  to  the  non-organized  deposits. 

As  above  mentioned  (page  447),  the  urine  of  healthy  individuals 
may  sometimes,  even  on  voiding,  be  cloudy  on  account  of  the 
phosphates  present,  or  become  so  after  a  little  while  because  of  the 
geparation  of  urates.  As  a  rule,  urine  just  voided  is  clear,  and  after 
cooling  shows  only  a  faint  cloud  (nubecula),  which  consists  of 
so-called  mucus,  a  few  epithelium-cells,  mucous  corpuscles,  and 
urate  particles.  If  an  acid  urine  is  allowed  to  stand,  it  will 
gradually  change;  it  becomes  darker  and  deposits  a  sediment  con- 
sisting of  uric  acid  or  urates,  and  sometimes  also  calcium-oxalate 
crystals,  in  which  yeast-fungus  and  bacteria  are  often  to  be  seen. 
The  cause  of  this  change,   which  the  earlier  investigators  called 

*'  ACID  FERMENTATION  OF  THE  URINE,"  is,  according  to  SCHERER,' 

the  mucus,  which  acts  like  an  enzyme  or  ferment,  producing  an 
acetic-acid  or  lactic-acid  fermentation,  precipitating  free  uric  acid 
or  acid  urates.     According  to  Neubauer,'^  an  actual  acid  fermen- 

1  Annal.  d   Cbem.  u.  Pbarm.,  Bd.  43  (1843). 

'  Neubauer  und  Vogel,  Analyse  des  Hams  (1876). 


URIXART  SEDIMENTS  AND   CALCULI.  565 

tatiou  may  occur  in  diabetic  urine,  but  this  seems  to  occur  only 
very  seldom,  and  according  to  Kohmaxx  '  an  acid  fermentation  of 
the  urine  in  Scherer's  sense  does  not  occur  under  normal  condi- 
tions. According  to  Voit  and  Hofmaxn  ^  a  separation  of  free  urio 
acid  and  acid  urates  may  be  produced,  without  any  increase  in  the 
acid  reaction,  by  an  exchange  of  the  di-hydrogen  alkali  phosphates 
with  the  alkali  urate  on  cooling  and  on  standing.  Simple  acid 
phosphate  and,  according  to  the  conditions,  acid  urate  or  free  uric 
acid  are  formed.  A  gradual  precipitation  of  uric  acid  may  occur 
not  only  without  an  increase  in  the  acid  reaction,  but,  because  of 
the  alkaline  reaction  of  the  simple  acid-alkali  phosphate,  it  may 
occur  with  a  simultaneous  decrease  of  the  same.  Eohmank  has 
presented  objections  to  this  statement.  He  claims  that  a  steady 
decrease  of  the  acid  reaction,  without  formation  of  ammonia,  caused 
by  the  above-mentioned  transformation  of  phosphates  and  urates 
does  not  take  place.  The  acid  reaction  does  not  decrease  until  the 
ammonia  increases.  According  to  Bence  Jones  '  the  precipitation 
of  the  uric  acid  and  urates  has  another  cause.  He  claims  that  the 
urine  contains  hyperacid  salts,  so-called  quadriurates  (see  page  4:78), 
which  gradually  split  into  uric  acid  and  biurates. 

Earlier  or  later,  sometimes  only  after  several  weeks,  the  reaction 
of  the  original  acid  urine  changes  and  becomes  neutral  or  alkaline. 
The  urine  has  now  passed  into  the  "  alkaline  fermentation," 
which  consists  in  the  decomposition  of  the  urea  into  carbon  dioxide 
and  ammonia  by  means  of  lower  organisms,  micrococcus  ureae, 
bacteria  urese,  and  other  bacteria.  Musculus  *  has  isolated  an 
enzyme  from  the  micrococcus  urese  which  decomposes  urea  and  is 
soluble  in  water.  During  the  alkaline  fermentation  volatile  fatty 
acids,  especially  acetic  acid,  may  be  produced,  chiefly  by  the 
fermentation  of  the  carbohydrates  of  the  urine  (Salkowski  *), 
A  fermentation  by  which  nitric  acid  is  reduced  to  nitrous  acid,  and 
another  where  sulphuretted  hydrogen  is  produced,  may  sometimes 
occur. 

If  the  alkaline  fermentation  has  only  advanced  so  far  as  to 
render  the  reaction  neutral,  then  we  often  find  in  the  sediment 

'  Zeitscbr.  f.  physiol.  Chem.,  Bd.  5. 

'  Sitzungsber.  d.  k.  b.  Akad.  d.  Wissenscb.,  1867,  Bd.  2,  S.  279.  Cited  from. 
R5bniann,  1.  c. 

3  Journ.  Cbem.  Soc,  Vol.  XV.  p.  8. 

*  Pfluger's  Arcb.,  Bd.  12. 

*  Zeit3cbr.  f .  pbysiol.  Cbem. ,  Bd.  13. 


566  THE   URINE. 

fragments  of  nric-acid  crystals,  sometimes  covered  with  prismatic 
crystals  of  alkali  urate;  dark-colored  spheres  of  ammonium  urate^ 
often  crystals  of  calcium  oxalate,  and  sometimes  crystallized  calcium 
phosphate  are  also  found.  Crystals  of  ammonium-magnesium  phos- 
phate  (triple  phosphate)  and  spherical  ammonium  urate  are  specially 
characteristic  of  alkaline  fermentation.  The  urine  in  alkaline  fer- 
mentation becomes  paler  and  is  often  covered  with  a  fine  membrane 
which  contains  amorphous  calcium  phosphate  and  glistening  crystals, 
of  triple  phosphate  and  numerous  micro-organisms. 

Non-organized  Sediments. 

Uric  Acid.  This  acid  occurs  in  acid  urines  as  colored  crystals 
which  are  identified  partly  by  their  form  and  partly  by  their 
property  of  giving  the  murexid  test.  On  warming  the  urine  they 
are  not  dissolved.  On  the  addition  of  caustic  alkali  to  the  sediment 
the  crystals  dissolve,  and  when  a  drop  of  this  solution  is  placed  on 
a  microscope-slide  and  treated  with  a  drop  of  hydrochloric  acid, 
small  crystals  of  uric  acid  are  obtained  which  are  easily  seen  under 
the  microscope. 

Acid  Urates.  These  only  occur  in  the  sediment  of  acid  or 
neutral  urines.  They  are  amorphous,  clay-yellow,  brick-red,  rose- 
colored,  or  brownish  red.  They  difller  from  other  sediments  in  that 
they  dissolve  on  warming  the  urine.  They  give  the  murexid  test, 
and  small  microscopic  crystals  of  uric  acid  separate  on  the  addition 
of  hydrochloric  acid.  Crystalline  alkali  urates  occur  very  rarely  in 
the  urine,  and  as  a  rule  only  in  such  as  have  become  neutral  but 
not  alkaline  by  the  alkaline  fermentation.  The  crystals  are  some- 
what similar  to  those  of  neutral  calcium  phosphate;  they  are  not 
dissolved  by  acetic  acid,  however,  but  give  a  cloudiness  therewith 
due  to  small  crystals  of  uric  acid. 

Ammonium  urate  may  indeed  occur  as  a  sediment  in  a  neutral 
urine  which  at  first  was  strongly  acid  and  has  become  neutralized 
by  the  alkaline  fermentation,  but  it  is  only  characteristic  of  am- 
moniacal  urines.  This  sediment  consists  of  yellow  or  brownish, 
rounded  spheres  which  are  often  covered  with  thorny-shaped  prisms 
and,  because  of  this,  are  rather  large  and  resemble  the  thorn-apple. 
It  gives  the  murexid  test.  It  is  dissolved  by  alkalies  with  the 
development  of  ammonia,  and  crystals  of  uric  acid  separate  on  the. 
addition  of  hydrochloric  acid  to  this  solution. 


NONORGANIZED   SEDIMENTS.  567 

Calcium  oxalate  occnrs  in  tlie  sediment  generally  as  small, 
shining,  strongly  refractive  quadratic  octahedra,  which  on  micro- 
scopical examination  remind  one  of  a  letter-envelope.  The  crystals 
can  only  be  mistaken  for  small,  not  fully  developed  crystals  of 
ammonium-magnesium  phosphate.  They  differ  from  these  by  their 
insolubility  in  acetic  acid.  The  oxalate  may  also  occur  as  flat,  oval, 
or  nearly  circular  disks  with  central  cavities  which  from  the  side 
appear  like  an  hour-glass.  Calcium  oxalate  may  occur  as  a  sedi- 
ment in  an  acid  as  well  as  in  a  neutral  or  alkaline  urine.  The 
quantity  of  calcium  oxalate  separated  from  the  urine  as  sediment 
depends  not  only  upon  the  amount  of  this  salt  present,  but  also 
upon  the  acidity  of  urine.  The  solvent  for  the  oxalate  in  the  urine 
seems  to  be  the  double-acid  alkali  phosphate,  and  the  greater  the 
quantity  of  this  salt  in  the  urine  the  greater  the  quantity  of  oxalate 
in  solution.  When,  as  above  mentioned  (page  565),  the  simple- 
acid  phosphate  is  formed  from  the  double-acid  phosphate,  on 
allowing  the  urine  to  stand,  a  corresponding  part  of  the  oxalate 
may  be  separated  as  sediment. 

Calcium  carhonate  occurs  in  considerable  quantities  as  sediment 
in  the  urine  of  herbivora.  It  occurs  in  but  small  quantities  as  a 
sediment  in  human  urine,  and  in  fact  only  in  alkaline  urines.  It 
either  has  almost  the  same  appearance  as  amorphous  calcium 
oxalate,  or  it  occurs  as  somewhat  larger  globules  with  concentric 
bands.  It  dissolves  in  acetic  acid  with  the  generation  of  gas,  which 
differentiates  it  from  calcium  oxalate.  It  is  not  yellow  or  brown 
like  ammonium  urate,  and  does  not  give  the  murexid  test. 

Calcium  sulphate  occurs  very  rarely  as  a  sediment  in  strongly  acid  urines. 
It  appears  as  long,  thin,  colorless  needles,  or  generally  as  plates  grouped 
together. 

Calcium  Phosphate.  The  calcium  teiphosphate,  Ca3(PO,)2, 
which  occurs  only  in  alkaline  urines,  is  always  amorphous  and 
occurs  partly  as  a  colorless,  very  fine  powder  and  partly  as  a  mem- 
brane consisting  of  very  fine  granules.  It  differs  from  the  amor- 
phous urates  in  that  it  is  colorless,  dissolves  in  acetic  acid,  but 
remains  undissolved  on  warming  the  urine.  Calcium  diphos- 
phate, CaHPO,  +  3H,0,  occurs  in  neutral  or  only  in  very  faintly 
acid  urine.  It  is  found  sometimes  as  a  thin  film  covering  the  urine, 
and  sometimes  as  a  sediment.  In  crystallizing  the  crystals  may  be 
single,  or  they  may  cross  one  another,  or  they  may  be  arranged  in 
groups  of  colorless,  wedge-shaped  crystals  whose  wide  end  is  sharply 


5t)8  TEE    UBINE. 

defined.  These  crystals  differ  from  crystalline  alkaline  urates  in 
that  they  dissolve  without  a  residue  in  dilute  acids  and  do  not  give 
the  murexid  test. 

Ammonium-magnesium  phosphate,  triple  phosphate,  may 
separate  of  course  from  an  amphoteric  urine  in  the  presence  of  a 
sufficient  quantity  of  ammonium  salts,  but  it  is  generally  character- 
istic of  a  urine  become  ammoniacal  through  alkaline  fermentation. 
The  crystals  are  so  large  that  they  may  be  seen  with  the  unaided  eye 
as  colorless  glistening  particles  in  the  sediment,  on  the  walls  of  the 
vessel,  and  in  the  film  on  the  surface  of  the  urine.  This  salt  forms 
large  prismatic  crystals  of  the  rhombical  system  (coffin-shaped) 
which  are  easily  soluble  in  acetic  acid.  Amorphous  magnesium 
triphosphate,  Mg^fPOJ,,  occurs  with  calcium  triphosphate  in  urines 
rendered  alkaline  by  a  fixed  alkali.  Crystalline  magnesium  phos- 
phate, Mg3(P0j2  +  22HjO,  has  been  observed  in  a  few  cases  in 
jiuman  urine  (also  in  horse's  urine)  as  strongly  refractive,  long 
rhombical  plates. 

Kyestein  is  the  film  which  appears  after  a  little  while  on  the  surface  of  the 
iurine.  This  coating,  which  was  formerly  considered  as  characteristic  of 
urine  in  pregnancy,  contains  various  elements,  such  as  fungus,  vibriones, 
•epithelium-cells,  etc.  It  often  contains  earthy  phosphates  and  triple  phosphate 
/Crystals. 

As  more  rare  sediments  we  find  cystin,  tyrosin,  hippuric  acid,  xantMn, 
Jimmatoidin.  In  alkaline  urine  blue  crystals  of  indigo  may  also  occur,  due  to 
.a  decomposition  of  indoxyl-glycuronic  acid. 

Urinary  Calculi. 

Besides  certain  pathological  constituents  of  the  urine,  all  those 
urinary  constituents  which  occur  as  sediments  take  part  in  the 
formation  of  the  urinary  calculi.  Ebsteijst  *  considers  the  essential 
difference  between  an  amorphous  or  crystalline  sediment  in  the 
urine  on  one  side  and  urinary  sand  or  large  calculi  on  the  other  to 
l)e  the  occurrence  of  an  organic  frame  in  the  last.  As  the  sediments 
which  appear  in  normal  acid  urine  and  in  a  urine  alkaline  through 
fermentation  are  different,  so  also  are  the  urinary  calculi  which 
appear  under  corresponding  conditions. 

If  the  formation  of  a  calculus  and  its  further  development  take 
place  in  an  undecomposed  urine,  it  is  called  a  primary  formation. 
If,  on  the  contrary,  the  urine  has  undergone  alkaline  fermentation 
and  the  ammonia  formed  thereby  has  given  rise  to  a  calculous 
formation  by  precipitating  ammonium  urate,  triple  phosphate,  and 
'  Die  Natur  und  Behandlung  der  Harnsteine,     Weisbaden,  1884. 


CRIXART  CALCULI.  569 

earthy  phosphates,  then  it  is  called  a  secondary  formation.  Snch 
a  formation  takes  place,  for  instance,  when  a  foreign  body  in  the 
bladder  produces  catarrh  accompanied  by  alkaline  fermentation. 

We  discriminate  between  the  naclens  or  nuclei — if  such  can  be 
seen — and  the  different  layers  of  the  calculus.  The  nucleus  may 
be  essentially  different  in  different  cases,  for  quite  frequently  it 
consists  of  a  foreign  body  introduced  into  the  bladder.  The 
calculus  may  have  more  than  one  nucleus.  In  a  tabulation  made 
by  Ultzmaxx  of  545  cases  of  urinary  calculi,  the  nucleus  in  80. 9<^ 
of  the  cases  consisted  of  uric  acid  (and  urates) ;  in  5.6,^,  of  calcium 
oxalate;  in  S.G*^,  of  earthy  phosphates;  in  1.4^,  of  cystin;  and  in 
3.3^,  of  some  foreign  body. 

During  the  growth  of  a  calculus  it  often  happens  that,  for  some 
reason  or  other,  the  original  calculus-forming  substance  is  covered 
with  another  layer  of  a  different  substance.  A  new  layer  of  the 
original  substance  may  deposit  on  the  outside  of  this,  and  this 
process  may  be  repeated.  In  this  way  a  calculus  consisting  origi- 
nally of  a  simple  stone  maybe  converted  into  a  so-called  compound 
stone  with  several  layers  of  different  substances.  Such  calculi  are 
always  formed  when  a  primary  formation  is  changed  into  a  secon- 
dary. By  the  continued  action  of  an  alkaline  urine  containing  pus, 
the  primary  constituents  of  an  originally  primary  calculus  may  be 
partly  dissolved  and  be  replaced  by  phosphates.  Metamorphosed 
urinary  calculi  are  formed  in  this  way. 

Uric-acid  calculi  are  very  abundant.  They  are  variable  in  size 
and  form.  The  size  of  the  bladder-stone  varies  from  that  of  a  pea 
or  bean  to  that  of  a  goose-egg.  Uric-acid  stones  are  always  colored ; 
generally  they  are  grayish  yellow,  yellowish  brown,  or  jiale  red- 
brown.  The  upper  surface  is  sometimes  entirely  even  or  smooth, 
sometimes  rough  or  uneven.  Xext  to  the  oxalate  calculus,  the  uric- 
acid  calculus  is  the  hardest.  Tlie  fractured  surface  shows  regular 
concentric,  unequally  colored  layers  which  may  often  be  removed 
as  shells.  These  calculi  are  formed  primarily.  Layers  of  uric  acid 
sometimes  alternate  with  other  layers  of  primary  formation,  most 
frequently  with  layers  of  calcium  oxalate.  The  simple  uric-acid 
calculus  leaves  very  little  residue  when  burnt  on  platinum  foil. 
It  gives  the  murexid  test,  but  there  is  no  material  development  of 
ammonia  when  acted  on  by  caustic  soda. 

Ammonium-urate  calculi  occur  as  primary  calculi  in  new-born 
or  nursing  infants,  rarely  in  grown  persons.     They  often  occur  a-; 


570  THE   URINE. 

a  secondary  formation.  The  primary  stones  are  small,  with  a  pale- 
yellow  or  dark-yellowish  surface.  When  moist  they  are  almost  like 
dough ;  in  the  dry  state  they  are  earthy,  easily  crumbling  into  a 
pale  powder.  They  give  the  murexid  test,  and  develop  much 
ammonia  with  caustic  soda. 

Calciu7n-oxalate  calculi  are,  next  to  uric-acid  calculi,  the  most 
abundant.  They  are  either  smooth  and  small  (hemp-seed  calculi) 
or  larger,  of  the  size  of  a  hen's  egg,  with  rough,  uneven  surface, 
or  their  surface  is  covered  with  prongs  (mulberet  calculi). 
These  calculi  produce  bleeding  easily,  and  therefore  they  often 
have  a  dark-brown  surface  due  to  decomposed  blood-coloring 
matters.  Among  the  calculi  occurring  in  man  these  are  the 
hardest.  They  dissolve  in  hydrochloric  acid  without  developing 
gas,  but  are  not  soluble  in  acetic  acid.  After  gently  heating  the 
powder  it  dissolves  in  acetic  acid  with  frothing.  After  strongly 
heating  the  powder  it  is  alkaline,  due  to  the  production  of  quick- 
lime. 

Phosphate  Calculi.  These,  which  consist  mainly  of  a  mixture 
of  the  normal  phosphate  of  the  alkaline  earths  with  triple  phos- 
phate, may  be  very  large.  They  are  as  a  rule  of  secondary  forma- 
tion, and  contain  besides  these  phosphates  also  some  ammonium 
urate  and  calcium  oxalate.  These  calculi  ordinarily  consist  of  a 
mixture  of  these  three  constituents,  earthy  phosphate,  triple  phos- 
phate, and  ammonium  urate,  surrounding  a  foreign  body  as  a 
nucleus.  Their  color  is  variable — white,  dingy  white,  pale  yellow, 
sometimes  violet  or  lilac-colored  (from  indigo-red).  The  surface  is 
always  rough.  Calculi  consisting  of  triple  phosphate  alone  are 
seldom  found.  They  are  ordinarily  small,  with  granular  or  radiated 
crystalline  fracture.  Stones  of  simple-acid  calcium  phosphate  are 
also  seldom  obtained.  They  are  white  and  have  a  beautiful  crystal- 
line texture.  The  phosphatic  calculi  do  not  burn  up,  and  the 
powder  dissolves  in  acid  without  effervescence,  and  the  solution 
gives  the  reactions  for  phosphoric  acid  and  alkaline  earths.  The 
triple-phosphate  calculi  generate  ammonia  on  the  addition  of  an 
alkali. 

Calcium- carbonate  calculi  occur  chiefly  in  herbivora.  They  are  seldom 
found  in  man.  They  have  mostly  chalky  properties,  and  are  ordinarily  white. 
They  are  completely  or  in  great  part  dissolved  by  acids  with  effervescence. 

Cystin  calculi  occur  but  seldom.  They  are  of  primary  formation,  of  various 
sizes,  sometimes  attaining  the  size  of  a  hen's  egg.  They  have  a  smooth  or 
rough  surlace,  are  white  or  pale  yellow,  and  have  a  crystalline  fracture.    They 


UETXART  CALCULI.  571 

are  not  very  hard  ;  they  burn  up  almost  entirely  on  platinum  foil,  burning 
with  a  bluish  flame.     They  give  the  above-mentioned  reactions  for  cystiu. 

Xanthin  calculi  are  very  rarely  found.  They  are  also  of  primary  forma- 
tion. They  vary  from  the  size  ot  a  pea  to  that  of  a  hen's  *:-gg.  They  are 
whitish,  yellowish  brown  or  cinnamon-brown  in  color,  medium  hard,  with 
amorphous  fracture,  and  on  rubbing  appear  like  wax.  They  burn  up  com- 
pletely when  heated  on  platinum  foil.  They  give  the  xanthin  reaction 
with  nitric  acid  and  alkali,  but  this  must  not  be  mistaken  for  the  murexidtest. 

Urostealitli  calculi  have  only  been  observed  a  few  times.  In  the  moist  state 
they  are  soft  and  elastic  at  the  temperature  of  the  body,  but  in  the  dry  state 
they  are  brittle,  wi  h  an  amorphous  fracture  and  waxy  appearance.  They 
buru  with  an  illuminating  flauie  when  heated  on  platinum  foil,  and  jri^nerate 
an  odor  similar  to  resin  or  shellac.  Such  a  calculus,  investigated  by  Krukex- 
BERG,'  consisted  of  paraflBue  derived  from  a  paraffine  bougie  used  as  a  sound 
im  the  patient.  Perhaps  the  urostealith  calculi  observed  .n  other  cases  had  a 
similar  origin,  although  the  substances  of  which  they  consisted  have  not  been 
closely  studied.  Horbaczewski  has  recently  analyzed  a  case  of  urostealith 
which,  to  all  appearances,  was  formed  in  the  bladder.  This  calculus  con- 
tained 25  p.  m.  water,  8  p.  m.  inorganic  bodies,  117  p.  m.  bodies  insoluble  in 
ether,  and  850  p.  m.  organic  bodies  soluble  in  ether,  among  which  were  515 
p.  m.  free  fatty  acids,  385  p.  m.  fat,  and  traces  of  chloresterin.  The  fatty  acids 
consisted  of  a  mixture  of  stearic,  palmitic,  and  probably  myristic  acids. 

Horbaczewski  '  has  also  analyzed  a  biadder-stoue  which  contained  958.7 
p.  m.  cholesterin. 

Fibrin  calculi  sometimes  occur.  They  consist  of  more  or  less  changed  fibrin 
coagulum.     On  burning  they  develop  an  odor  of  burnt  horn. 

The  cliemical  iyivestigation  of  urinary  calculi  is  of  great  practical 
importance.  To  make  such  an  examination  actually  instructive  it 
is  necessary  to  investigate  separately  the  diiferent  layers  which  con- 
stitute the  calculus.  For  this  purpose  saw  the  calculus,  which  has 
been  wrapped  in  paper,  with  a  fine  saw  so  that  the  nucleus  is  sawed 
through  and  accessible.  Then  peel  off  the  different  layers,  or,  if 
the  stone  is  to  be  kept,  scrape  off  enough  of  the  powder  from  each 
layer  for  examination.  This  powder  is  then  tested  by  heating  on 
platinum  foil.  It  must  not  be  forgotten  that  a  calculus  is  never 
entirely  burnt  up,  and  also  that  it  is  never  so  free  from  organic 
matter  that  on  heating  it  does  not  carbonize.  Do  not,  therefore, 
lay  too  great  stress  on  a  very  insignificant  unburnt  residue  or  on  a 
very  small  amount  of  organic  matter,  but  consider  the  calculus  in 
the  former  case  as  completely  burnt  and  in  the  latter  as  not  burnt. 

When  the  powder  is  in  great  part  burnt  up,  but  a  signific-mt 
quantity  of  unburnt  residue  remains,  then  the  powder  in  question 
contains  as  a  rule  urates  mixed  with  inorganic  bodies.  In  such 
cases  remove  the  urate  with  boiling  water,  and  then  test  the  filtrate 
for  uric  acid  and  the  expected  bases.  The  residue  is  then  tested 
according  to  the  following  schema  of  Heller,  which  is  well  adapted 
to  the  investigation  of  urinary  calculi.  In  regard  to  more  detailed 
examination  the  reader  is  referred  to  special  works  on  the  subject. 

'  Chem.  Untersuch.  z.  wissensch.  Med.,  Bd.  2.  Cited  from  Maly's 
Jahresber.,  Bd.  19,  S.  422. 

*  Zeitschr.  f.  physiol.  Chem.,  Bd.  18. 


572 


THE    UBINE. 


On  beating  the  powder  on  platinum  foil  it 


Does  not  burn 


The  powder  when  treated 
with  HCl 


Does  not  effervesce 


The  gently  heated 
powder  with  HCl 


The  powder  when 

moistened  with  a 

little  KHO 


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^.  £«    CD^ 
O 

P  d'^ 
"^  P 


.  P 


^B  ? 
§1.3 

O   pj   ^ 

5  p'  p" 


p.  p 

CD    CD 


CD  >^ 

2  o 


03     1-3 

^  p' 


CD    i 

o  &, 

P    CD 


O 


Without  flame 


^6 


2   ^   << 

f^  ci  5 

&CD    <^ 


cr 

I^CD 

P'a 

CD    P 

P 

•  IT  CD 


CD    ^ 


M    °, 


Oq    P 


^TP- 


The  powder 

gives  the 
murexid  test 


The  powder 

when  treated 

with  KHO 

gives 


1:^ 


CHAPTER   XVI. 

THE   SKIN   AND   ITS   SECRETIONS. 

In  the  structure  of  the  skin  of  man  and  vertebrates  many  differ- 
ent kinds  of  substances  occur  which  have  already  been  treated  of, 
such  as  the  constituents  of  the  epidermis  formation,  the  connective 
and  fatty  tissues,  the  nerves,  muscles,  etc.  Among  these  the 
different  horn-formations,  the  hair,  nails,  etc.,  whose  chief  constit- 
uent, keratin,  has  been  spoken  of  in  another  chapter  (Chap.  II), 
are  of  special  interest. 

The  cells  of  the  horny  formation  show,  in  proportion  to  their 
age,  a  different  resistance  to  chemical  reagents,  especially  fixed 
alkalies.  The  younger  the  horn-cell  the  less  resistance  it  has  to  the 
action  of  alkalies;  with  advancing  age  the  resistance  becomes 
greater,  and  the  cell-membranes  of  many  horn-formations  are  nearly 
insoluble  in  caustic  alkalies.  Keratin  occurs  in  the  horn-formation 
mixed  with  other  bodies,  from  which  it  is  isolated  with  difficulty. 
Among  these  bodies  the  mineral  constituents  in  many  cases  occupy 
a  prominent  place  because  of  their  quantity.  Hair  leaves  on  burn- 
ing 5-70  p.  m.  ash,  which  may  contain  in  1000  parts  230  parts 
alkali  sulphates,  140  parts  calcium  sulphate,  100  parts  iron  oxide, 
and  even  400  parts  silicic  acid.  Dark  hair  on  burning  seems  gen- 
erally, but  not  always,  to  yield  more  iron  oxide  than  blond.  The 
nails  are  rich  in  calcium  phosphate,  and  the  feathers  rich  in  silicic 
acid. 

The  granules  occurring  in  the  stratum  granulosnm  of  the  skin 
consist  of  a  substance  which  has  been  called  ehicUn,  and  which  is 
considered  as  an  intermediate  step  in  the  transformation  of  the 
protoplasm  into  keratin.  The  chemical  nature  of  this  substance  is 
unknown. 

The  skin  of  invertebrates  has  been  the  subject,  in  a  few  cases, 
of  chemical  investigation,  and  in  these  animals  various  substances 

573 


574  THE  SKIN  AND  ITS  SECRETIONS. 

have  been  found,  of  which  a  few,  though  little  studied,  are  worth 
discussing.  Among  these  bodies  tunicin,  which  is  found  especially 
m  the  tunic  of  the  tunicata,  and  the  widely  diffused  chitin,  found 
in  the  cuticle-formation  of  invertebrates,  are  of  interest. 

Tunicin.  Cellulose  seems,  according  to  the  investigations  of  Ambronn,'  to 
occur  ratUer  extensively  in  the  animal  kingdom  in  the  arthropoda  and  the 
mollusks.  It  has  been  known  lor  a  long  time  as  the  tunic  of  the  tuincnta,  and 
this  animal  cellulose  was  called  tunicin  by  Berthelot.^  According  to  the 
recent  inve  tigations  of  Winterstein  ^  there  does  not  seem  to  exist  any  marked 
difference  between  tunicin  and  ordinary  cellulose.  On  boiling  with  dilute  acid 
tunicin  yields  dextrose,  as  shown  first  by  Franchimokt  *  and  later  confirmed 

by  WlJSTERSTEIN. 

Chitin  is  not  found  in  vertebrates.  In  invertebrates  chitin  is 
alleged  to  occur  in  several  classes  of  animals;  but  it  can  only  be 
positively  asserted  that  true,  typical  chitin  is  found  only  in  articu- 
lated animals,  in  which  it  forms  the  chief  organic  constituent  of  the 
shell,  etc.  According  to  Keawkow  ^  chitin  of  the  shell,  etc.,  does 
not  seem  to  occur  free,  but  in  combination  with  another  snbstance, 
probably  a  proteid-like  body. 

According  to  Suxdwik  °  the  composition  of  chitin  is  probably 
Cg„H,„„]Sr„0.jg  +  ^^^(H^O),  where  n  may  vary  between  1  and  4,  and  it 
is  probably  an  amine  derivative  of  a  carbohydrate,  with  the  general 
formula  ^(Cj^Hj^O,,,).  According  to  Keawkow''  chitin  shows 
different  origins  by  its  unequal  behavior  with  iodine,  and  he  there- 
fore conckides  that  there  must  exist  quite  a  group  of  chitins,  which 
seem  to  be  amine  derivatives  of  different  carbohydrates  such  as 
dextrose,  glycogen,  dextrins,  etc.  Chitin  is  decomposed  on  boiling 
with  mineral  acids  and  yields,  as  shown  by  Leddeehose,*  glucosa- 
mine and  acetic  acid.  Schmiedebeeg  "  therefore  considers  chitin 
as  a  probable  acet};!  acetic  acid  combination  of  glucosamine.  If,  as 
previously  mentioned  (page  345),  the  chondroitic-sulphuric  acid 
contains  a  glucosamine  group,  as  made  probable  by  the  investiga- 
tions of  Schmiedebeeg,  then,  according  to  Schmiedebeeg,  glu- 
cosamine forms  the  bridge  which  leads  from  the  chitin  of  lower 

J  Maly's  Jahresber..  Bd   20,  S.  318. 

^  Annal.  de  chiiu.  et  phys.,  Tome  56,  Compt.  rend.,  Tome  47. 

»  Zeit'-chr.  f.     hysiol.  Chem.,  Bd.  18. 

*  Ber.  de  deutsch.  chem.  Gesellsch.,  Bd.  12. 

5  Zeitsclir,  f.  Biologie,  Bd.  29. 

'  Zeitschr.  f.  physiol.  Chem.,  Bd.  5. 

■>  L.  c. 

8  Zeitschr.  f.  physiol.  Chem.,  Bdd.  2  u.  4. 

9  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  28. 


CHITTN.  575 

animals  to  the  cartilage  of  higher  organized  beings.  According  to 
the  recent  investigations  of  Gilson  '  and  Winterstein'  several 
fungi  seem  to  contain  chitin  instead  of  cellulose.  On  heating  chitia 
with  alkali  and  a  little  water  to  180°  C,  a  cleavage  takes  place, 
according  to  Hoppe-Seyler  and  Araki,^  with  the  formation  of  a 
new  substance,  cJiitosan,  Cj^Hj^N^Oj^,  which  retains  the  shape  of 
the  original  chitin  and  the  splitting  off  of  acetic  acid.  Chitosan  is 
dissolved  by  dilute  acids,  also  acetic  acid,  and  is  colored  violet  by  a 
dilute  iodine  solution.  It  splits  into  acetic  acid  and  glucosamine 
by  the  action  of  hydrochloric  acid.  On  heating  with  acetic  anhy- 
dride it  is  converted  into  a  chitin-like  substance,  which  is  not  iden- 
tical with  chitin  and  contains  at  least  three  acetyl  groups. 

In  the  dry  state  chitin  forms  a  white,  brittle  mass  retaining  the 
form  of  the  original  tissue.  It  is  insoluble  in  boiling  water,  alcohol, 
ether,  acetic  acid,  dilute  mineral  acids,  and  dikite  alkalies.  It  is 
soluble  in  concentrated  acids.  It  is  dissolved  without  decomposing 
in  cold  concentrated  hydrochloric  acid,  but  is  decomposed  by  boil- 
ing hydrochloric  acid.  When  chitin  is  dissolved  in  concentrated 
sulphuric  acid  and  the  solution  dropped  into  boiling  water  and  then 
boiled,  we  obtain  a  substance  (glucosamine  or  glucose)  which 
reduces  copper  suboxide  in  alkaline  solutions.  According  to 
Krawkow  the  various  chitins  behave  differently  with  iodine  or 
with  sulphuric  acid  and  iodine  in  that  some  are  colored  reddish 
brown,  blue,  or  violet,  while  others  are  not  colored  at  all. 

Chitin  may  be  easily  prepared  from  the  wings  of  insects  or  from 
the  shells  of  the  lobster  or  the  crab,  the  last  mentioned  having  first 
been  extracted  by  an  acid  so  as  to  remove  the  lime-salts.  The 
wings  or  shells  are  boiled  with  caustic  alkali  until  they  are  white, 
afterward  washed  with  water,  then  with  dilute  acid  and  water,  and 
lastly  extracted  with  alcohol  and  ether.  If  chitin  so  prepared  is 
dissolved  in  cold,  concentrated  sulphuric  acid  and  diluted  with  cold 
water,  then  pure  chitin  separates  out,  having  been  set  free  from  the 
combination  with  the  other  body  (Krawkow). 

Hyalin  is  the  chief  organic  constituent  of  the  walla  of  hydatid  cysts.  From 
a  cliemical  point  of  view  it  stands  close  to  chitin,  or  between  it  and  the  i)ro- 
teid.  In  old  and  more  transparent  sacs  it  is  tolerably  free  fr  m  mineral 
bodies,  but  in  younger  sacs  it  contains  a  great  quantity  (16^)  of  lime-salts 
(carbonate,  phosphate,  and  sulphate). 

»  Compt.  rend..  Tome  120. 

•  Ber.  d.  deutsch.  chem.  Gesellsch.,  1894-1895. 

•Zeitschr.  f.  physiol.  Chem.,  Bd.  20. 


576  THE  SKIN  AND  ITS  SECRETIONS. 

According  to  LiJCKE  '  its  composition  is: 

C  H  N  O 

From  old  cysts 45.3        6.5        5.2        43.0 

From  young  cysts 44.1         6.7        4.5        44.7 

It  differs  from  keratin  on  tlie  one  hand  and  from  proteids  on  the  other  by 
the  absence  of  sulphur,  also  by  its  yielding,  when  boiled  with  dilute  sulphuric 
acid,  a  variety  of  sugar  in  large  quantities  (50^),  which  is  reducing,  fermenta- 
ble, and  dextrogyrate.  It  differs  from  chitin  by  the  property  of  being  gradu- 
ally dissolved  by  caustic  potash  or  soda,  or  by  dilute  acids  ;  also  by  its  solu- 
bility on  heating  with  water  to  150°  C. 

Tlie  coloring  matters  of  the  skin  and  hor?i-formations  are  of 
different  kinds,  bat  have  not  been  much  studied.  Those  occurring 
in  the  Malpighian  layer  of  the  skin,  especially  of  the  negro,  and  the 
black  or  brown  pigment  occurring  in  the  hair  belong  to  the  group 
of  coloring  matters  which  have  received  the  name  melanins. 

Melanins.  This  group  includes  several  different  varieties  of 
amorphous  black  or  brown  pigments  which  are  insoluble  in  water, 
alcohol,  ether,  chloroform,  and  dilute  acids,  and  which  occur  in  the 
skin,  hair,  epithelium-cells  of  the  retina,  in  sepia,  in  certain  patho- 
logical formations,  and  in  the  blood  and  urine  in  disease.  Of  tliese 
pigments  there  are  a  few,  such  as  the  melanin  of  the  eye  and  that 
from  the  melanotic  sarcomata  of  horses,  the  Mppomelanin  (Neivtcki 
and  Berdez^),  which  are  soluble  with  difficulty  in  alkalies,  while 
others,  such  as  the  pigment  of  the  hair  and  the  coloring  matter  of 
certain  pathological  swellings  in  man,  the  phymatorusin  (NEiq'CKi 
and  Berdez),  are  easily  soluble  in  alkalies. 

Among  the  melanins  there  are  a  few,  for  example,  the  choroid 
pigment,  which  are  free  from  sulphur;  others,  on  the  contrary,  as 
the  pigment  of  the  hair  and  of  horse-hair,  are  rather  rich  in 
sulphur  (2-4^),  while  the  phymatorusin  found  in  certain  swellings 
and  in  the  urine  (Nencki  and  Berdez,  K.  MoR]srER ')  is  very  rich 
in  sulphur  (8-10^).  Whether  any  of  these  pigments,  especially  the 
phymatorusin,  contains  any  iron  or  not  is  an  important  though 
disputed  point,  for  it  leads  to  the  question  whether  these  pigments 
are  formed  from  the  blood-coloring  matters.  The  pigment, 
phymatorusin,  isolated  by  Nekcki  and  Berdez  from  melanotic 
sarcomata,  is,  according  to  them,  free  from  iron  and  is  not  a  deriva- 
tive of  haemoglobin.  K.  Morner  and  later  also  Brandl  and 
L.  Pfeiffer  ^  found,  on  the  contrary,  that  this  pigment  did  contain 

'  Virchow's  Arch.,  Bd.  19. 

*  Arch.  f.  exp.  Path.  u.  Pharm. ,  Bdd.  20  u.  24. 

^  Zeitschr.  f.  physiol.  Chem.,  Bd.  11,  which  contains  all  the  older  litera- 
ture, and  Bd.  12. 

4  Zeitschr.  f.  Biologic,  Bd.  26. 


MELANIN8.  577 

iron,  and  they  consider  it  as  a  derivative  of  the  blood-pigments. 
The  difficulties  which  attend  the  isolation  and  purification  of  the 
melanins  have  not  been  overcome  in  certain  cases,  while  in  others 
it  is  questionable  whether  the  final  product  obtained  has  not  another 
composition  than  the  original  coloring  matter,  owing  to  the  ener- 
getic chemical  processes  resorted  to  in  its  purification.  Under  such 
circumstances  it  seems  that  a  tabulation  of  the  analyses  of  different 
melanin  preparations  made  up  to  the  present  time  are  of  secondary 
importance. 

Among  the  above-mentioned  bodies  belonging  to  the  melanin 
group,  the  phymatorusin  prepared  by  Nencki  and  Sieber  from 
melanotic  sarcomata,  and  that  prepared  by  K.  Morner  from  the 
sarcomata  and  the  urine  of  a  patient,  seem  to  be  of  special  interest. 
Phymatorusin  is  an  amorphous  dark-brown  pigment  soluble  in  alka- 
lies or  alkali  carbonates,  but  insoluble  in  warm  50-75^  acetic  acid. 
In  alkaline  solution  it  shows  no  absorption-bands.  According  to 
Nencki  and  Sieber  it  is  free  from  iron,  but  Morner,  on  the 
contrary,  claims  that  it  does  contain  iron.  Morner  found  for  this 
coloring  matter  from  tumors  (A)  and  from  urine  (B)  the  following 
composition  calculated  on  the  substance  considered  as  ash-free: 


A 

B 

c 

55.32—56.13 

55.76 

H 

5.65—  6.33 

5.95 

N 

12.30 

12.27 

S 

7.97 

9.01 

Fe 

0.063—0.081 

0.30 

Nencki  and  Sieber  have  also  shown  that  other  melanins,  not 
identical  with  phymatorusin,  occur  in  melanotic  sarcomata  of  man. 
The  investigations  of  Brandl  and  Pfeiffer  seem  to  lead  to  -a, 
similar  conclusion. 

The  coloring  matter  or  matters  of  human  hair  contain  a  low 
quantity  of  nitrogen,  8.5^  (Sieber  '),  and  a  variable  but  high  quan- 
tity of  sulphur,  2.71-4.10^.  The  considerable  quantity  of  iron 
oxide  found  in  the  ash  does  not  seem  to  belong  to  the  pigments. 

In  addition  to  tlie  coloring  matters  of  the  human  skin  we  may  also  here  treat 
of  tlie  pigments  foand  in  the  slcin  or  epidermis- formation  of  animals. 

The  be;iutifiil  ci)lor  of  the  feathers  of  many  birds  depends  in  certain  cases- 
on  purely  ])liysical  causes  (interference-phenomena),  but  in  other  cases  on  col- 
oring matters  of  various  kinds.  Such  a  coloring  matter  is  the  amorphous  red- 
dish violet  tiiracin,  which  contains  7%  copper,  and  whose  spectrum  is  very  similar 
to  that  of  oxy haemoglobin.     Kkukenberg  '  found  a  large  number  of  coloring- 

•  Arch.  f.  exp.  Path.  u.  Pharm.,  Bd.  20. 

»  See  Physiol.  Studien,  Abth.  5,  u.  2,  Reih.  Abtb.  1,  S.  151,  Abth.  2,  S.  1,  und 
Abtb.  3,  S.  128. 


578  THE  SKIN  AND  ITS  SECRETIONS. 

matters  in  birds'  featlaers,  namely,  zooerythriii,  zoofulviii,  turacoverdin,  zoom- 
bin,  psittacofulvin,  and  others  wliicli  cannot  be  enumerated  here. 

Tetronerythrin,  so  named  by  Wurm,'  is  a  red  amorphous  pigment,  which  is 
sohible  in  alcohulaud  ether,  and  which  occurs  in  the  red  warty  spots  over  the 
•eyes  of  the  heath-cock  and  the  grouse,  and  which  is  very  widely  spread  among- 
the  invertebrates  (Halliburton,^  De  Merejkowski/  MacMunn  ■*).  Besides 
tetronerythrin  MacMunn  found  in  the  shells  of  crabs  and  lobsters  a  blue  col- 
oring matter,  cyanocrystallin,  which  turns  red  with  acids  and  by  boiling- 
water.  Hmnatoporphyrin,  according  to  MacMunn,^  also  occurs  in  the  integu- 
ments of  certain  lower  animals. 

In  addition  to  the  coloring  matters  thus  far  mentioned  a  few  others  found 
in  certain  animals  (though  not  in  the  skin)  will  be  spoken  of. 

Carminic  acid,  or  the  red  coloring  matter  of  cochineal,  has  the  composition 
CnHisOio.  It  gives  sugar  on  boiling  with  acids,  but  this  does  not  correspond 
with  the  recent  statements  of  Liebekmann.^  The  beautiful  purple  solution  of 
ammonium  carminate  has  two  absorption-bands  between  Z)  and  ^  which  are 
similar  to  those  of  oxy haemoglobin.  These  bands  lie  nearer  to  E  and  closer  to- 
gether and  are  less  sharply  defined.  Purple  is  the  evaporated  residue  from 
the  purple-violet  secretion,  caused  by  the  actitm  of  the  sunlight,  from  the  so- 
called  ' '  purple  gland  "  of  the  tunic  <  f  certain  species  of  murex  and  purpura. 
Its  chemical  nature  has  not  been  investigated. 

x\mong  the  remaining  coloring  matters  found  in  invertebrates  we  may  men- 
tion hkie  stentorin,  actiniochrovi,  boneUin,  polyperythrin,  pentacrinin,  ante- 
donin,  crustaceorubin,  janihinin,  and  chloropkyll. 

Sebum  when  freshly  secreted  is  an  oily  semi-fluid  mass  which 
solidifies  on  the  upper  surface  of  the  skin,  forming  a  greasy  coating. 
The  quantity  is  very  different  in  different  persons.  Hoppe- 
Seyler  '  has  found  a  body  similar  to  casein,  besides  albumin  and 
fat,  in  the  sebum.  Cholesterin  is  also  found  in  this  fat,  and  in 
especially  large  quantities  in  the  vernix  caseosa.  The  solids  of  the 
sebum  consist  chiefly  of  fat,  epithelium-cells,  and  protein  bodies; 
the  vernix  caseosa  consists  chiefly  of  fat. 

On  account  of  the  generally  diffused  view  that  wax  of  the  plant 
epidermis  serves  as  protection  for  the  inner  parts  of  the  fruit  and 
plant,  LiEBREiCH  ®  has  suggested  that  the  combinations  of  fatty 
acids  with  monatomic  alcohols  are  the  reason  for  the  resistance 
property  of  the  waxes  as  compared  with  the  glycerin  fats.  He  also 
considers  that  the  cholesterin  fats  play  the  role  of  a  protective  fat 
in  the  animal  kingdom,  and  he  has  been  able  to  detect  cholesterin 
fat  in  human  skin  and  hair,  in  vernix  caseosa,  whale-bone,  torLoise- 

'  Zeitschr.  f.  wissensch.  Zool.,  1871.  Cited  from  Maly's  Jahresber.,  Bd.  1, 
S.  52. 

»  Journal  of  Physiol.,  Vol.  6. 

*  Compt.  rend.,  Tome  93. 
*Proc.  Eoy.  Soc,  1883. 

*  Quart.  Journ.  of  Micros.  Sc,  1877,  and  Journal  of  Physiol.,  Vol.?.  . 

*  Ber.  d.  deutsch.  chem.  Gesellsch.,  Bd.  18. 
'  Physiol.  Chem.,  S.  760. 

«  Virchow's  Arch.,  Bd.  121. 


SEBUM  AND   CERUMEN.  579 

shell,  cow's  horn,  the  feathers  and  beaks  of  several  birds,  the 
prickles  of  the  hedgehog  and  porcupine,  the  hoofs  of  horses,  etc. 
He  draws  the  following  conclusion  from  this,  namel}',  that  the 
cholesterin  fats  always  apjjear  in  combination  with  the  keratinous 
substance,  and  that  the  cholesterin  fat,  like  the  wax  of  plants, 
serves  as  protection  for  the  skin-surface  of  animals. 

Cerumen  is  a  mixture  of  the  secretion  of  the  sebaceous  and 
sweat  glands  of  the  cartilaginous  part  of  the  outer  organs  of  hearing. 
It  contains  chiefly  soaps  and  fat,  and  besides  these  a  red  substance 
easily  soluble  in  alcohol  and  with  a  bitter-sweet  taste. 

The  preputial  secretion,  smegma  prcBpntii,  contains  chiefly  fat, 
also  cholesterin  and  ammonium  soaps,  wliich  probably  are  produced 
from  decomposed  urine.  The  hippuric  acid,  benzoic  acid,  and 
calcium  oxalate  found  in  the  smegma  of  the  horse  have  probably 
the  same  origin. 

We  may  also  consider  as  a  preputial  secretion  tlie  castoreum,  whicli  is  se- 
creteil  by  two  peculiar  glandular  sacs  in  the  prepuce  of  the  bei.ver.  This  cas- 
toreum is  a  mixture  of  proteids,  fat,  resins,  traces  of  ph.  nol  (volatile  oil),  and 
a  non-nitrogenizfd  body,  cttstorin,  crvstalliziug  in  four-sided  needles  from  alco- 
hol, insolable  in  cold  water,  but  somewhat  soluble  in  boiling  water,  and  whose 
composition  is  little  known. 

Wool-fat,  or  the  so-called  fat-sweat  of  sheep,  is  a  mixture  of  the  secretion  of 
the  sudoriparous  and  sebaceous  glands.  We  find  in  the  watery  extract  a  large 
quantity  of  potassium  which  is  combined  with  organic  acid,  volatile  and  non- 
volatile fatty  acids,  benzoic  acid,  phenol-sulphuric  acid,  lactic  acid,  malic 
acid,  succinic  acid,  and  others.  The  fat  contains  among  other  bodies 
abundant  quantities  of  ethers  of  fatty  acids  wiih  cholesterin  and  isocholes- 
terin. 

The  secretion  of  the  coccygeal  glands  of  ducks  and  geese  contains  a  body 
similar  to  casein,  besides  albumin,  uuclein,  lecithin,  and  fat,  but  no  sugar  (De 
JONGE  ').  Poisonous  bodies  have  been  found  in  the  secretion  of  the  skin  of  the 
salamander  and  the  toad  respectively,  samandariii  (Zalesky  ')  and  hufidin 
(JOKNARA  and  Casali  ^). 

The  Sweat.  Of  the  secretions  of  the  skin,  whose  quantity 
amounts  to  about  ^  of  the  weight  of  the  body,  a  disproportionally 
large  part  consists  of  water.  Xext  to  the  kidneys,  the  skin  in  man 
is  the  most  important  means  for  the  elimination  of  water.  As  the 
glands  of  the  skin  and  the  kidneys  stand  near  to  each  other  in 
regard  to  their  functions,  they  may  to  a  certain  extent  act  vica- 
riously for  oue  another. 

The  circumstances  which  influence  the  secretion  of  sweat  are  very 
numerous,  and  the  quantity  of  sweat  secreted  must  consequently 

'  Zeitschr.  f.  physiol  Chem.,  Bd.  3. 

'  Iloppe-Seyler's  Med   chem.  Untersuch.,  S.  85. 

»  Riv.  di  Bologna,  1873.     Cited  from  Maly's  Jahresber.,  Bd.  3,  S.  64. 


580  THE  SKIN  AND  118  SECRETIONS. 

vary  very  considerably.  The  secretion  differs  for  different  parts  of 
the  skin,  and  it  has  been  stated  that  the  perspiration  of  the  cheek, 
that  of  tlie  palm  of  the  hand,  and  that  under  the  arm  stand  to  each 
other  as  100  :  90  :  45.  From  the  unequal  secretion  on  different  parts 
of  the  body  it  follows  that  no  results  as  to  the  quantity  of  secretion  for 
the  entire  surface  of  the  body  can  be  calculated  from  the  quantity 
secreted  by  a  small  part  of  the  skin  in  a  given  time.  In  determin- 
ing the  total  quantity  a  stronger  secretion  is  as  a  rule  produced,  and 
as  the  glands  can  with  difficulty  work  for  a  long  time  with  the  same 
energy,  it  is  hardly  correct  to  estimate  the  quantity  of  secretion  per 
24  hours  from  a  stroug  secretion  enduring  only  a  short  time. 

The  perspiration  obtained  for  investigation  is  never  quite  pure^ 
but  contains  cast-off  epidermis-cells,  also  cells  and  fat-globules  from 
the  sebaceous  glands.  Filtered  sweat  is  a  clear,  colorless  fluid  with 
a  salty  taste  and  of  different  odors  from  different  parts  of  the  body. 
The  physiological  reaction  is  acid,  according  to  most  statements. 
Under  certain  conditions  also  an  alkaline  sweat  may  be  secreted 
(Trumpt  and  Luchsinger,'  Heuss'').  An  alkaline  reaction  may 
also  depend  on  a  decomj)osition  with  the  formation  of  ammonia. 
According  to  a  few  investigators  the  physiological  reaction  is 
alkaline,  and  an  acid  reaction  depends,  according  to  these  investiga- 
tors, upon  an  admixture  of  fatty  acids  from  the  sebum.  Moriggia  * 
found  that  the  sweat  from  herbivora  was  ordinarily  alkaline,  while 
that  from  carnivora  was  generally  acid.  According  to  Smith* 
horse's  sweat  is  strongly  alkaline.  The  specific  gravity  of  human 
sweat  is  1.003-1.005. 

Perspiration  contains  977.4-995.6  p.  m.,  average  988.2  p.  m., 
water,  and  4.4-22.6  p.  m.,  average  11.80  p.  m.,  solids.  The 
organic  bodies  are  neutral  fats,  cliolesterin,  volatile  fatty  acids, 
traces  of  proteid  (according  to  Leclerc  '  and  Smith  °  habitually  in 
horses,  according  to  Gaube^  regularly  in  man,  and  according  to 

1  Pfluger's  Arch.,  Bd.  18. 

'  Monatshefte  f.  prakt.  Dermat. ,  Bd.   14.     Cited  from  Maly's  Jaliresber. , 
Bd.  22,  S.  193. 

*  Molescliott,  Untersucli.  zur  Naturlire,  Bd.    11;    also  Maly's  Jaliresber. ,. 
Bd.  3,  S.  126. 

*  Journal  of  Physiol.,  Bd.  11.     In  regard  to  the  older  literature  on  sweat 
see  Hermann's  Handbucb,  Bd.  5,  Thl.  1,  S.  431  u.  543. 

*  Compt.  rend.,  Tome  107. 
«L.  c. 

«  Maly's  Jabresber.,  Bd.  22,  S.  193. 


THE  SWEAT.  581 

Lefbe  '  sometimes  after  hot  baths,  in  Bright's  disease,  and  after 
the  use  of  pilocar^Din),  also  creatinin  (Capranica''),  aromatic 
oxy acids,  ethereal-sulphuric  acids  of  phenol  and  slcatoxyl  (Kast')^ 
but  not  of  indoxyl,  and  lastly  urea.  The  quantity  of  urea  has  been 
determined  by  Akgutinsky/  In  two  steam-bath  experiments,  in 
wliich  in  the  coarse  of  ^  and  f  hour  respectively  he  obtained  225 
and  330  c.  c.  sweat,  he  found  1.61  and  1.24  p.  m.  urea.  Of  the 
total  nitrogen  of  the  sweat  in  these  two  experiments  68.5  and  74.9^ 
respectively  belong  to  the  urea.  From  Argutinsky's  experiments, 
and  also  from  those  of  Cramer,'  it  follows  that  of  the  total  nitrogen 
a  portion  not  to  be  disregarded  is  eliminated  by  the  sweat.  This 
portion  was  indeed  12^  in  an  experiment  of  Cramer  at  high  tem- 
perature and  powerful  muscular  activity.  C-ramer  has  also  found 
ammonia  in  the  sweat.  In  uraemia,  and  in  ischuria  in  cholera,  urea 
may  be  secreted  in  such  quantities  by  the  sweat-glands  that  crystals 
deposit  upon  the  skin.  The  mineral  bodies  consist  chiefly  of 
sodium  chloride  with  some  potassium  chloride,  alkali  sulphate,  and 
phosphate.  The  relative  quantities  of  these  in  perspiration  differ 
materially  from  the  quantities  in  the  urine  (Favre,"  Kast).  The 
relationship,  according  to  Kast,  is  as  follows: 


Chlorine 

:  Phosphate 

Sulphate 

In  perspiration 

1 

0.0015 

0.009 

In  urine 

1 

0.1320 

0.397 

Kast  found  that  the  proportion  of  ethereal-sulphuric  acid  to 
the  sulphate  sulphuric  acid  in  sweat  was  1  :  12.  After  the  admin- 
istration of  aromatic  substances  the  ethereal-sulphuric  acid  does  not 
increase  to  the  same  extent  in  the  sweat  as  in  the  urine  (see 
Chapter  XV). 

Sugar  may  pass  into  the  sweat  in  diabetes,  but  the  passage  of  the  bile-col- 
oring matters  has  not  been  positively  shown  in  this  secretion.  Benzoic  acid, 
succinic  acid,  tartaric  acid,  iodine,  arsenic,  mercuric  chloride,  and  quinine  pass 
into  the  sweat.  Uric  acid  has  also  been  found  in  the  sweat  in  gout,  and  cystin 
in  cy^tinura. 

Chromhidrosis  is  the  name  given  to  the  secretion  of  colored  sweat.  Some- 
times sweat  has  been   observed   to   be  colored    blue   by  indigo   (Bizio  ■■),  by 

'  Leabe,  Virchow's  Arch.,  Bdd.  48  u.  .50,  and  Arch.  f.  klin.  Med.,  Bd.  7. 

«  xMaly's  Jahresber.,  Bd.  12,  S.  190. 

s  Zeitschr.  f.  physiol.  Chem.,  Bd.  11,  S.  501. 

«Pfluger's  Arch.,  Bd.  46. 

*  Arch.  f.  Hygiene,  Bd.  10. 

*  Compt.  rend.,  Tome  35,  and  Arch,  gener.  de  med.,  1853  (Ser.  5),  Vol.  2. 
'  Wien.  Sitzungsber.,  Bd.  39. 


582  THE  SKIN  AND  ITS  SECRETIONS. 

pyocyanin,  or  by  ferro-phospliate  (Kollmann  ').  True  blood-sweat,  in  whicb' 
blood-corpuscles  exude  from  tbe  openings  of  the  glands,  liave  also  been  ob- 
served. 

The  exchange  of  gas  through  the  shin  in  man  is  of  very  little- 
importance  compared  with  the  exchange  of  gas  by"  the  langs.  The 
absorption  of  oxygen  by  the  skin,  which  was  first  shown  by 
KEG]srAULT  and  Reiset,  is  very  small.  The  quantity  of  carbon 
dioxide  eliminated  by  the  skin  increases  with  the  rise  of  temperature 
(AuBERT,"  EoHRiG,'  FuBiN^i  and  RoNCHi^).  It  is  also  greater  in 
light  than  in  darkness.  It  is  greater  during  digestion  than  when 
fasting,  and  greater  after  a  vegetable  than  after  an  animal  diet 
(FuBiNi  and  Eonchi).  The  quantity  calculated  by  various  inves- 
tigators for  the  entire  skin  surface  in  24  hours  varies  between  2.2S 
and  32.8  grms.^  In  certain  animals,  as  in  frogs,  the  exchange  of 
gas  through  the  skin  is  of  great  importance. 

As  tiie  exchange  of  gas  through  the  skin  in  man  and  mammalia 
is  very  small,  it  follows  that  the  injurious  and  dangerous  effects 
caused  by  covering  the  skin  with  varnish,  oil,  or  the  like  can 
hardly  depend  on  a  prevented  exchange  of  gas.  After  varnishing 
the  skin  there  is  a  considerable  loss  of  heat,  and  the  animal  quickly 
dies.  If  the  animal,  on  the  contrary,  be  guarded  from  this  loss  of 
heat,  it  may  be  saved,  or  at  least  kept  alive  for  a  longer  time. 
This  effect  was  supposed  to  be  due  to  a  poisoning  caused  by  a  reten- 
tion of  one  or  more  substances  of  the  perspiration  {perspiralile 
retentum),  accompanied  by  fever  and  increased  loss  of  heat  through 
the  skin;  but  this  statement  has  not  been  substantiated.  This 
phenomenon  seems  to  be  due  to  other  causes,  and  at  least  in  certain 
animals  (rabbits)  death  seems  to  ensue  from  the  paralysis  of  the 
vaso-motor  nerves.  In  anastomosis  the  loss  of  heat  through  the  skin 
seems  to  be  increased  to  such  an  extent  that  the  animal  dies  from 
the  lowered  temperature. 

'  Wurzb.  med.  Zeitscb.,  Bd.  7,  S.  251.  Cited  from  Gorup-Besanez,  Lebrb., 
4.  Aufl.,  S.  555. 

*  Pfiiiger's  Arcb.,  Bd.  6. 

s  Deutscb.  kiln.,  1872,  S.  209. 

*  Molescbott's  Metersucb.  zur  Naturbbre.,  Bd.  12. 
«  See  Hoppe-Seyler,  Pbysiol.  Cbem.  S.  580. 


CHAPTER  XVII. 

CHEMISTRY   OF   RESPIRATION. 

DuEiNG  life  a  constant  exchange  of  gases  takes  place  between 
the  animal  body  and  the  surrounding  medium.  Oxygen  is  inspired 
and  carbon  dioxide  expired.  This  exchange  of  gases,  which  is  called 
respiration,  is  brought  about  in  man  and  vertebrates  by  the  nutri- 
tive fluids,  blood  and  lymph,  which  circulate  in  the  body  and 
which  are  in  constant  communication  with  the  outer  medium  on 
one  side  and  the  tissue-elements  on  the  other.  Such  an  exchange 
of  gaseous  constituents  may  take  place  wherever  the  anatomical 
conditions  offer  no  obstacle,  and  in  man  it  may  go  on  in  the  intes- 
tinal tract,  through  the  skin,  and  in  the  lungs.  As  compared  with 
the  exchange  of  gas  in  the  lungs,  the  exchange  already  mentioned 
which  occurs  in  the  intestine  and  through  the  skin  is  very  insig- 
nificant. For  this  reason  we  will  discuss  in  this  chapter  only  the 
exchange  of  gas  between  the  blood  and  the  air  of  the  lungs  on  one 
side,  and  the  blood  and  lymph  and  the  tissues  on  the  other.  The 
first  is  often  designated  external  respiration,  and  the  other  internal 
respiration. 

In  this  chapter  we  will  accordingly  first  discuss  the  gases  of 
the  blood  and  lymph,  and  then  the  exchange  of  gas  in  the  lungs 
and  tissues.  The  quantitative  circumstances  of  the  exchange  of  o-as 
stand  in  such  close  relationship  to  metabolism  in  general  that  they 
will  be  treated  of  in  the  last  chapter,  on  the  income  and  output 
of  the  body  under  different  conditions.  Only  the  chief  points 
in  the  methods  commonly  employed  for  measuring  the  exchange 
of  gas  will  be  mentioned. 

I.  The  Gases  of  the  Blood. 

Since   the    pioneer    investigations   of    Magnus   and    Lothar 
Meyer  the  gases  of  the  blood  have  formed  the  subject  of  repeated 
careful  investigations  by  prominent  experimenters,  among  whom  we 
must  mention  first  C.  Ludwig  and  his  pupils  and  E.  Pfluger  and 

583 


584  CHEMISTRY  OF  RESPIRATION. 

liis  school.  By  these  investigations  not  only  has  science  been 
enriched  by  a  mass  of  facts,  but  also  the  methods  themselves  liave 
been  made  more  perfect  and  accurate.  In  regard  to  these  methods, 
as  also  in  regard  to  the  laws  of  the  absorption  of  gases  by  liquids, 
dissociation,  and  other  questions  belonging  here,  the  reader  is 
referred  to  complete  text-books  on  physiology,  on  physics,  and  on 
gasometric  analysis. 

The  gases  occurring  in  blood  under  physiological  conditions  are 
oxygen.,  carton  dioxide.,  and  nitrogen.  The  last-mentioned  gas  is 
found  only  in  very  small  quantities,  on  an  average  of  1.8  vol,  per 
cent.  The  quantity  is  here,  as  in  all  following  experiments,  calcu- 
lated for  0°  C.  and  760  mm.  pressure.  The  nitrogen  seems  to  be 
simply  absorbed  into  the  blood,  at  least  in  great  part.  It  appears 
to  play  no  part  in  the  processes  of  life,  and  its  quantity  varies  but 
slightly  in  the  blood  of  different  blood-vessels. 

The  oxygen  and  carbon  dioxide  behave  otherwise,  as  their 
quantities  have  significant  variations,  nob  only  in  the  blood  from 
different  blood-vessels,  but  also  because  many  conditions,  such  as  a 
difference  in  the  rapidity  of  circulation,  a  different  temperature, 
jest  and  activity,  cause  a  change.  In  regard  to  the  gases  they 
contain  the  greatest  difference  is  observable  between  the  blood  of 
ithe  arteries  and  that  of  the  veins. 

The  quantity  of  oxygen  in  the  arterial  blood  of  dogs  is  on  an 
average  22  vols,  per  cent  (Pfluger).  In  human  blood  SEXSCHEisrow 
found  about  the  same  quantity,  namely,  21.6  vols,  per  cent.  Lower 
figures  have  been  found  for  rabbit's  and  bird's  blood,  respectively 
1.3.2^  and  10-15^  (Waltee,  Joltet).  Venous  blood  has  very 
variable  quantities  of  oxygen.  Ludwig  and  Sczelkow  found  6.8^ 
oxygen  in  the  venous  blood  of  resting  muscles,  and  a  still  smaller 
quantity  in  the  venous  blood  of  active  muscles.  Oxygen  is  entirely 
absent  from  blood  after  asphyxiation,  or  occurs  only  as  traces.  The 
venous  blood  of  the  glands  seems,  on  the  contrary,  during  secretion 
to  be  richer  in  oxygen  than  ordinary  venoas  blood.  By  summarizing 
a  great  number  of  analyses  by  different  experimenters  Zuntz  has 
calculated  that  the  venous  blood  of  the  right  side  of  the  heart 
contains  on  an  average  7.15^  less  oxygen  than  the  arterial  blood. 

The  quantity  of  carton  dioxide  in  the  arterial  blood  of  dogs  is 
30  to  40  vols,  per  cent  (Ludwig,  Setschenow,  Pfluger,  P.  Bert, 
and  others),  most  generally  about  40^,  Setsciienow  found  40.3 
vols,  per  cent  in  human  arterial  blood.     The  quantity  of  carbon 


OXYGEN  ABSORPTION.  .KSf) 

dioxide  in  venons  blood  varies  still  more  (Ludwig,  Pfluger  and 
their  pupils,  P.  Bert,  Mathieu  and  Urbaist,  and  others). 
According  to  the  calculations  of  Zuntz  the  venous  blood  of  the 
right  side  of  the  heart  contains  about  8.2j^  more  carbon  dioxide 
than  the  arterial.  The  average  amount  may  be  put  down  as  48 
vols,  per  cent.  Holmgren  found  in  blood  after  asphyxiation  even 
69.21  vols,  per  cent  carbon  dioxide.' 

Oxygen  is  absorbed  only  to  a  small  extent  by  the  plasma  or 
serum,  in  which  Pfluger  found  but  0.26^.  The  greater  part  or 
nearly  all  of  the  oxygen  is  loosely  combined  with  the  haemoglobin. 
The  quantity  of  oxygen  which  is  contained  in  the  blood  of  the  dog 
corresponds  closely  to  the  quantity  which  from  the  activity  of  the 
haemoglobin  we  should  expect  to  combine  with  oxygen,  and  also  the 
quantity  of  hagmoglobin  in  canine  blood.  It  is  difficult  to  ascertain 
how  far  the  circulating  arterial  blood  is  saturated  with  oxygen,  as 
immediately  after  bleeding  a  loss  of  oxygen  always  takes  place. 
Still  it  seems  to  be  unquestionable  that  it  is  not  quite  completely 
saturated  with  oxygen  in  life. 

The  question  whether  ozone  occurs  in  the  blood  is  to  be  answered 
decidedly  in  the  negative.  It  is  not  only  impossible  to  detect  ozone 
in  the  blood,  but  the  possibility  of  the  occurrence  of  ozone  in  the 
fluids  and  tissues  is  even  a  jjriori  to  be  denied.  Ozone  acts  as 
nascent  oxygen;  and  as  easily  oxidizable  substances  occur  in  the 
organism  which  combine  with  nascent  oxygen,  ozone,  if  such  a 
formation  should  take  place  at  all,  would  be  destroyed  instantly. 
But  such  a  formation  of  ozone  in  the  animal  body  cannot  be 
admitted.  Ozone  may  indeed  be  formed  by  slow  oxidation,  since 
the  nascent  oxygen  formed  in  consequence  combines  with  neutral 
oxygen,  forming  ozone;  but  in  the  animal  organism  the  nascent 
oxygen  must  be  combined  with  the  oxidizable  substances  before  it 
can  form  ozone. 

It  was  formerly  believed  that  the  hgemoglobin  acted  as  an 
**  ozone-exciter,"  possessing  the  property  of  converting  the  inactive 
oxygen  of  the  air  into  ozone.  The  red  blood-corpuscles  can  by 
themselves  also  give  a  blue  color  with  tincture  of  guaiacum,  which 
is  markedly  seen  when  this  tincture  is  dried  on  blotting-paper  and 
a  drop  of  blood  previously  diluted  with  5-10  vols,  water  is  added. 

'  All  the  figures  given  above  may  be  found  in  Zuntz's  "  Die  Gase  des 
Blutes"  in  Hermann's  Handbuch  d.  Physiol.,  Bd.  4,  Tbl.  2,  S.  33-43,  which 
also  contains  detailed  statements  and  the  pertinent  literature. 


586  CHEMISTRY  OF  RESPIRATION. 

According  to  Pflugee,'  we  are  here  dealing  (see  page  134)  with  a 
decomposition  and  gradual  oxidation  of  hsemoglobin,  in  which 
processes  the  neutral  oxygen  is  split,  setting  free  oxygen  atoms. 

The  carbon  dioxide  of  the  blood  occurs  in  part,  and  indeed, 
according  to  the  investigations  of  Alex.  Schmidt,^  Zui^tz,'  and 
L.  Feedericq,*  to  the  extent  of  at  least  one  third,  in  the  blood- 
corpuscles,  and  also  in  part,  and  in  fact  the  greatest  part,  in  the 
plasma  and  serum  respectively. 

The  carbon  dioxide  of  the  red  corpuscles  is  loosely  combined, 
and  the  constituent  uniting  with  the  CO^  of  the  same  seems  to  be 
the  alkali  combined  with  phosphoric  acid,  oxyhsemoglobin  or  haemo- 
globin  and  globulin  on  one  side  and  the  hsemoglobin  itself  on  the 
other.  That  in  the  red  corpuscles  alkali  phosphate  occurs  in  such 
quantities  that  it  may  be  of  importance  in  the  combination  with 
carbon  dioxide  is  not  to  be  doubted,  and  we  must  admit  that  from 
the  diphosphate,  by  a  greater  partial  pressure  of  the  carbon  dioxide, 
monophosphate  and  alkali  carbonate  are  formed,  while  by  a  lower 
partial  pressure  of  the  carbon  dioxide  the  mass  action  of  the  phos- 
phoric acid  comes  again  into  play,  so  that,  with  the  carbon  dioxide 
becoming  free,  a  re-formation  of  alkali  diphosphate  takes  place.  It 
is  generally  admitted  that  the  blood-coloring  matters,  especially  the 
oxyhaemoglobin,  which  can  expel  carbon  dioxide  from  sodium 
carbonates  in  vacuo,  act  like  an  acid ;  and  as  the  globulins  also  act 
like  acids  (see  below),  this  body  may  also  occur  in  the  blood-cor- 
puscles as  an  alkali  combination.  The  alkali  of  the  blood-corpuscles 
must  therefore,  according  to  the  law  of  mass  action,  be  divided 
between  the  carbon  dioxide,  phosphoric  acid,  and  the  other  con- 
stituents of  the  blood-corpuscles  which  are  considered  as  acid  acting, 
and  among  these  especially  the  blood-pigments,  as  the  globulin  can 
hardly  be  of  importance  because  of  its  small  quantity.  By  greater 
mass  action  or  greater  partial  pressure  of  the  carbon  dioxide,  bicar- 
bonate must  be  formed  at  the  expense  of  the  diphosphates  and  the 
other  alkali  combinations,  while  at  a  diminished  partial  pressure  of 
the  same  gas,  with  the  escape  of  carbon  dioxide,  the  alkali  diphos- 
phate and  the  other  alkali  combinations  must  be  re-formed  at  the 
cost  of  the  bicarbonate, 

'  Pfliiger's  Arch.,  Bd.  10,  S.  253. 

^  Ber.  d.  k.  sacks.  Gesellsch.  d.Wissenscli.,  Math.-phys.  Klasse,  Bd.  19, 1867. 

3  Centralbl.  f.  d.  med.  Wissenscli.,  1867,  S.  529. 

*  Recherclies  sur  la  constitution  du  Plasma  sanguin,  1878,  p.  50-51. 


CARBON  DIOXIDE  OF  THE  BLOOD-CORPUSCLES.        587 

Haemoglobin  must  nevertheless,  as  the  investigations  of  Set- 
SCHENOW  '  and  Zuntz,''  and  especially  those  of  Bohr  ^  and  Torup,* 
have  shown,  be  able  to  hold  the  carbon  dioxide  loosely  combined 
even  in  the  absence  of  alkali.  Bohr  has  also  found  that  the 
dissociation  curve  of  the  carbon-dioxide  haemoglobin  corresponds 
essentially  to  the  curve  of  the  absorption  of  carbon  dioxide,  on 
which  ground  he  and  Torup  consider  the  hsemoglobiu  itself  as  of 
importance  in  the  binding  of  the  carbon  dioxide  of  the  blood  and 
not  its  alkali  combinations.  In  regard  to  this  question  the  condi- 
tions are  not  quite  clear.  If  carbon  dioxide  is  allowed  to  act  on 
haemoglobin,  it  unites  (Bohr,  Tokup)  with  the  colored  atomic 
group  of  the  hsemoglobin,  splitting  off  proteid,  and  from  this 
haemoglobin,  so  decomposed,  oxyhaemoglobin  cannot  be  formed  by 
the  action  of  oxygen.  According  to  Bohr,  for  each  gramme  of 
hsemoglobin  at  +  18.4°  C.  and  a  pressure  of  30  mm.  2.4  c.  cm. 
carbon  dioxide  are  combined;  and  since  in  the  arterial  blood  nearly 
all  the  hfemogiobin  exists  as  oxyhfemoglobin,  it  is  difficult  to 
understand  how  the  hsemoglobin  can  be  of  any  great  importance  in 
the  binding  of  the  carbon  dioxide  of  the  blood.  According  to  the 
recent  investigations  of  Bohr  °  this  condition  is  explained  by  the 
property  of  the  haemoglobin  to  take  up  both  gases,  carbon  dioxide 
and  oxygen,  simultaneously  and  independently  of  each  other.  It 
takes  place,  as  admitted  by  Bohr,  by  the  oxygen  probably  uniting 
with  the  pigment  nucleus,  and  the  carbon  dioxide  with  the  proteid 
component. 

The  chief  part  of  the  carbon  dioxide  of  the  blood  is  found  in  the 
blood-plasma  or  the  blood-serum,  which  follows  from  the  fact  that 
the  serum  is  richer  in  carbon  dioxide  than  the  corresponding  blood 
itself.  By  experiments  with  the  air-pump  on  blood-serum  it  has 
been  found  that  the  chief  part  of  the  carbon  dioxide  contained  in 
the  serum  is  given  off  in  a  vacuum,  while  a  smaller  part  can  be 
pumped  out  only  after  the  addition  of  an  acid.  The  red  corpuscles 
also  act  as  an  acid,  and  therefore  in  blood  all  the  carbon  dioxide  is 
expelled  in  vacuo.  Hence  a  part  of  the  carbon  dioxide  is  firmly 
chemically  combined  in  the  serum. 

'  Centralbl.  f.  d.  med.   Wissensch.,   1877.     See  also  Zuntz  in    Hermann's 
Handbuch,  S.76. 
»  L   c,  S.  76. 

s  See  Maly's  Jahresber..  Bd.  17,  S.  115. 
*Md.,  S.  115. 
»  See  foot-note  4,  p.  139. 


588  CHEMISTRY  OF  RESPIBATION. 

Absorption  experiments  with  blood-serum  have  shown  us  further 
that  the  carbon  dioxide  which  can  be  pumped  out  is  in  great  part 
loosely  chemically  combined,  and  from  this  loose  combination  of  the 
carbon  dioxide  it  necessarily  follows  that  the  serum  must  also 
contain  simply  absorbed  carbon  dioxide.  For  the  form  of  binding 
of  the  carbon  dioxide  contained  in  the  sernm  or  the  plasma  we  find 
the  three  following  possibilities:  1.  A  part  of  the  carbon  dioxide  is 
simply  absorbed;  '2.  Another  part  is  loosely  chemically  combined; 
3.  A  third  part  is  in  firm  chemical  combination. 

The  quantity  of  simply  absorbed  carbon  dioxide  has  not  been 
exactly  determined.  Setschenow  '  considers  the  quantity  in  dog- 
serum  to  be  about  -^^  of  the  total  quantity  of  carbon  dioxide. 
According  to  the  tension  of  the  carbon  dioxide  in  the  blood  and  its 
absorption  coefficient,  the  quantity  seems  to  be  still  smaller. 

The  quantity  of  firmly  chemically  combined  carbon  dioxide  in 
the  blood-serum  depends  upon  the  quantity  of  simple  alkali  car- 
bonate in  the  serum.  This  quantity  is  not  known,  and  it  cannot 
be  detei'mined  either  by  the  alkalinity  found  by  titration,  nor  can 
it  be  calculated  from  the  excess  of  alkali  found  in  the  ash,  because 
the  alkali  is  not  only  combined  with  carbon  dioxide,  but  also  with 
other  bodies,  especially  with  proteid.  The  quantity  of  firmly 
chemically  combined  carbon  dioxide  cannot  be  ascertained  after 
pumping  out  in  vacuo  without  the  addition  of  acid,  because  to  all 
appearances  certain  active  constituents  of  the  serum,  acting  like 
acids,  expel  carbon  dioxide  from  the  simple  carbonate.  The 
quantity  of  carbon  dioxide  not  expelled  from  dog-serum  by  vacuum 
alone  without  the  addition  of  acid  amounts  to  4.9  to  9.3  vols,  per 
cent,  according  to  the  determinations  of  Pelugee.^ 

From  the  occurrence  of  simple  alkali  carbonates  in  the  blood- 
serum  it  naturally  follows  that  a  part  of  the  loosely  combined  carbon 
dioxide  of  the  serum  which  can  be  pumped  out  must  occur  as 
bicarbonate.  The  occarrence  of  this  combination  in  the  blood- 
serum  has  also  been  directly  shown.  In  experiments  with  the 
pamp,  as  well  as  in  absorption  experiments,  the  serum  behaves  in 
other  ways  as  a  solution  of  bicarbonate,  or  carbonate  of  a  corre- 
sponding concentration;  and  the  behavior  of  the  loosely  combined 
carbon  dioxide  in  the  serum  can  be  explained  only  by  the  occurrence 

'  Centralbl.  f.  d.  med.  Wissensch.,  1877,  No.  35. 

«  E.  Pfluger,  Ueber  die  Kolilensaure  des  Blutes.    Bonn,  1864.    S.  11.    Cited 
from  Zuntz  in  Hermann's  Handbiicb,  S.  65. 


CAEBOX  DIOXIDE  OF   THE  SERUM.  589 

of  bicarbonate  iu  the  serum.  By  meaus  of  vacuum  the  serum 
always  allows  much  more  thau  one  half  of  the  carbon  dioxide  to  be 
expelled,  aud  it  follows  from  this  that  in  tiie  pumping  out  not  only 
may  a  dissociation  of  the  bicarbonate  take  place,  but  also  a  conver- 
sion of  the  double  sodium  carbonate  into  a  simple  salt.  As  we 
know  of  no  other  carbon-dioxide  combination  besides  tlie  bicarbon- 
ate in  the  serum  from  which  the  carbon  dioxide  can  be  set  free  by 
simple  dissociation  in  vacuo,  we  are  obliged  to  assume  that  the  serum 
must  contain  other  faint  acids,  in  addition  to  the  carbon  dioxide, 
which  contend  with  it  for  the  alkalies,  aud  which  expel  the  carbon 
dioxide  from  simple  carbonates  in  vacuo.  The  carbon  dioxide 
which  is  expelled  by  means  of  the  pump  and  which,  without  regard 
to  the  simple  absorbed  quantity,  is  generally  designated  as  "  loosely 
chemically  combined  carbon  dioxide,"  is  thus  only  obtained  in  part 
in  dissociable  loose  combination;  in  part  it  originates  from  the 
simple  carbonates,  from  which  it  is  expelled  in  vacuo  by  other  faint 
acids. 

These  faint  acids  are  thought  to  be  in  part  phosphoric  acid  and 
in  part  globulins.  The  importance  of  the  alkali  phosphates  for  the 
carbon  dioxide  combination  has  been  shown  by  the  investigations 
of  Feenet;  but  the  quantity  of  these  salts  in  the  serum  is,  at  least 
in  certain  kinds  of  blood,  for  example  in  ox-serum,  so  small  that  it 
can  hardly  be  of  importance.  In  regard  to  the  globulins  Set- 
SCHEXOW  is  of  the  opinion  that  they  do  not  act  as  acids  themselves, 
but  form  a  combination  with  carbon  dioxide,  producing  carbooloba- 
linic  acid,  which  unites  with  the  alkali.  According  to  Sertoli,' 
whose  views  have  lately  found  a  supporter  in  Torup,  the  globulins 
themselves  are  the  acids  which  are  combined  with  the  alkali  of  the 
blood-serum.  In  both  cases  the  globulins  would  form,  directly  or 
indirectly,  that  chief  constituent  of  the  plasma  or  of  the  blood- 
serum  which,  according  to  the  law  of  the  action  of  masses,  contends 
with  the  carbon  dioxide  for  the  alkalies.  By  a  greater  partial 
pressure  of  the  cai'bon  dioxide  the  latter  deprives  the  globulin  alkali 
of  a  part  of  its  alkali,  and  bicarbonate  is  formed;  by  low  partial 
pressure  the  carbon  dioxide  escapes,  and  the  bicarbonate  is  abstracted 
by  the  globulin  alkali. 

In  the  foregoing  it  has  been  assumed  that  the  alkali  is  the  mos-t 
essential  and  important  constituent  of  the  blood-serum,  as  well  as 
of  the  blood  in  general,  in  uniting  with  the  carbon  dioxide.  The 
'  Hoppe-Seyler,  Med.  chein.  Untersuch. 


590  CHEMISTRY  OF  BESPIRATION. 

fact  that  the  quantity  of  carbon  dioxide  in  the  blood  greatly  dimin- 
ishes with  a  decrease  in  the  quantity  of  alkali  strengthens  this 
assumption.  Such  a  condition  is  found,  for  example,  after  poison- 
ing with  mineral  acids.  Thus  "Waltee  '  found  only  2-3  vols,  per 
cent  carbon  dioxide  in  the  blood  of  rabbits  into  whose  stomachs 
hydrochloric  acid  had  been  introduced.  In  the  comatose  state  of 
diabetes  mellitus  the  alkali  of  the  blood  seems  to  be  in  great  part 
saturated  with  acid  combinations,  /?-oxybutyric  acid  (Stadel- 
MAN^N,''  Minkowski),  and  Minkowski'  found  only  3.3  vols,  per 
cent  carbon  dioxide  in  the  blood  in  diabetic  coma. 

In  the  above  we  have  emphasized  the  fact  that  the  oxygen  in 
the  blood  occurs  in  a  dissociable  combination  with  the  hgemoglobin, 
and  that  for  the  formation  of  this  combination,  oxyhsemoglobin, 
a  distinct  partial  pressure  of  the  oxygen  is  necessary  for  every 
variation  in  temperature.  Also  that  the  carbon  dioxide  of  the 
blood,  that  which  is  contained  in  the  blood-corpuscles  as  well  as 
that  in  the  plasma,  occurs  mostly  in  combinations  which  are 
dependent  to  a  great  extent  upon  the  partial  pressure  of  the  carbon 
dioxide.  Hence  for  the  study  of  the  exchange  of  gases  between 
the  blood  and  the  alveolar  air  on  one  side,  and  the  blood  and  the 
tissues  on  the  other,  special  regard  must  be  paid  to  the  question 
as  to  how  far  this  exchange  of  gases  is  the  result  of  the  law  of 
diffusion  and  how  far  other  forces  take  part  in  it;  also  the  tension 
of  the  oxygen  and  the  carbon  dioxide  is  of  the  greatest  importance. 
For  these  reasons  it  is  best  to  treat  of  these  questions  in  that  section 
of  this  chapter  dealing  with  the  exchange  of  gas  in  the  lungs  and 
tissues. 

Gases  of  the  Lymph  and  Secretions. 

The  gases  of  the  lymph  are  the  same  as  in  the  blood-serum,  and 
the  lymph  stands  close  to  the  blood-serum  in  regard  to  the  quantity 
of  the  various  gases,  as  well  as  to  the  kind  of  carbon  dioxide  combi- 
nation. The  investigations  of  Daenhardt  and  HENSEisr^on  the 
gases  of  human  lymph  are  at  hand,  but  it  still  remains  a  question 
whether  the  lymph  investigated  was  quite  normal.     The  gases  of 

^  Arc^i.  f.  exp.  Path.  u.  Pharm.,  Bd.  7. 
"^  Ihid.,  Bd    17. 

3  Mittheil.  a.  d.  med.  Klink  in  KQnigsberg,  1888,  and  Arch.  f.  exp.  Path.  u. 
Phann  ,  Bd.  18 

*  Virchow's  Arch.,  Bd.  37. 


OASES  OF  THE  LYMPH  AND    THE  SECRETIONS.        591 

normal  dog -lymph  were  first  investigated  by  the  author.'  These 
gases  contained  traces  of  oxygen  and  consisted  of  37.4-53.1^  CO, 
and  1,6^  N  at  0°  C.  and  760  mm.  Hg  pressure.  Abont  one  half  of 
the  carbon  dioxide  was  firmly  chemically  combined.  The  quantity 
was  greater  than  in  the  seram  from  arterial  blood,  bnt  smaller  than 
from  venous  blood. 

The  remarkable  observation  of  Buchner  '  that  the  lymph  col- 
lected after  asphyxiation  is  poorer  in  carbon  dioxide  than  that  of 
the  breathing  animal  is  explained  by  Zuntz  '  by  the  formation  of 
acid  immediately  after  death  in  the  tissues,  and  especially  in  the 
lymphatic  glands,  and  this  acid  decomposes  the  alkali  carbonates  of 
the  lymph  in  part. 

The  secretions  with  the  exception  of  the  saliva,  in  which 
Pfluger*  and  KiJLZ  ^  fonnd  respectively  0.6  and  Ifo  oxygen,  are 
free  from  oxygen.  The  quantity  of  nitrogen  is  the  same  as  in  blood, 
and  the  chief  mass  of  the  gases  consists  of  carbon  dioxide.  The 
quantity  of  this  gas  is  chiefiy  dependent  upon  the  reaction,  i.e., 
upon  the  quantity  of  alkali.  This  follows  from  the  analyses  of 
Pfluger."  He  found  19^  carbon  dioxide  removable  by  the  air- 
pump  and  54^  firmly  combined  carbon  dioxide  in  a  strongly  alka- 
line bile,  but  on  the  contrary  6.6^  carbon  dioxide  removable  by 
the  air-pump  and  0.8^  firmly  combined  carbon  dioxide  in  a  neutral 
bile.  Alkaline  saliva  is  also  very  rich  in  carbon  dioxide.  As  average- 
for  two  analyses  made  by  Pfluger  '  of  submaxillary  saliva  of  a  dog 
we  have  27.5^  carbon  dioxide  removable  by  the  air-pump  and  47.4^ 
chemically  combined  carbon  dioxide,  making  a  total  of  74.9^. 
KiJLZ  *  found  a  maximum  of  65.78^  carbon  dioxide  for  the  parotid 
saliva,  of  which  3.31^  was  removable  by  the  air-pump  and  62.47j^ 
was  firmly  chemically  combined.  From  these  and  other  statements 
on  the  quantity  of  carbon  dioxide  removable  by  the  air-pump  and 
chemically  combined  in  the  alkaline  secretions  it  follows  that  bodies 

'  Ber.  d.  k.  sachs.  Gesellsch.  d.  Wissensch. ,  Math.-phys.  Klasse,  Bd.  23, 
1871. 

*  Arbeiten  a.  d.  physiol.  Anstalt  zu  Leipzig,  1876. 
3  Hermann's  Handbuch,  Bd.  4,  Thl.  3,  S.  85. 

*  Pfliiger's  Arch.,  Bd.  1. 

*  Zeitscbr.  f.  Biologie,  Bd.  23. 

*  Pfliiger's  Arch.,  Bdd.  1  u.  2. 
'L.  c. 

*  L.  c.  It  seems  as  if  Klilz's  results  were  not  calculated  at  760  mm.  Hg, 
but  rather  at  1  mm. 


592  CHEMISTRY  OF  RESPIRATION. 

occur  in  them,  although  not  in  appreciable  quantities,  which  are 
analogous  to  the  albuminous  bodies  of  the  blood-serum  and  which 
act  like  faint  acids. 

The  acid  or  at  any  rate  non-alkaline  secretions,  urine  and  milk, 
contain,  on  the  contrary,  considerably  less  carbon  dioxide,  which  is 
nearly  all  removable  by  the  air-pump,  and  a  part  seems  to  be  loosely 
combined  with  the  sodium  phosphate.  The  figures  found  by 
Pfluger  for  the  total  quantity  of  carbon  dioxide  in  milk  and  urine 
are  10  and  18.1-19.7^  respectively. 

EwALD '  has  made  investigations  on  the  quantity  of  gas  in 
pathological  transudations.  He  found  only  traces,  or  at  least  only 
very  insignificant  quantities,  of  oxygen  in  these  fluids.  The  quantity 
of  nitrogen  was  about  the  same  as  in  blood.  The  quantity  of 
carbon  dioxide  was  greater  than  in  the  lymph  (of  dogs),  and  in 
certain  cases  even  greater  than  the  blood  after  asphyxiation  (dog's 
blood).  The  tension  of  the  carbon  dioxide  was  greater  than  in 
venous  blood.  In  exudations  the  quantity  of  carbon  dioxide, 
especially  that  firmly  combined,  increases  with  the  age  of  the  fluid, 
while,  on  the  contrary,  the  total  quantity  of  carbon  dioxide,  and 
especially  the  quantity  firmly  combined,  decreases  with  the  quan- 
tity of  pus-corpuscles. 

II.  The  Exchange  of  Gas  between  the  Blood  on 
the  one  hand  and  Pulmonary  Air  and  the 
Tissues  on  the  Other* 

In  the  introduction  (Chapter  I,  p.  3)  it  was  stated  that  we  are 
to-day  of  the  opinion,  derived  especially  from  the  researches  of 
Pflugek  and  his  pupils,  that  the  oxidations  of  the  animal  body  do 
not  take  place  in  the  fluids  and  juices,  but  are  connected  with  the 
form-elements  and  tissues.  It  has,  it  is  true,  been  shown  by  Alex. 
Schmidt^  and  Pfluger'  that  oxidations  take  place  in  the  blood, 
although  only  to  a  slight  extent;  but  these  oxidations  depend,  it 
seems,  upon  the  form-elements  of  the  blood,  hence  it  does  not  con- 
tradict the  above  statement  that  the  oxidations  occur  exclusively  in 
the  cells  and  chiefly  in  the  tissues. 

»  C.  A.  Ewald,  Arch.  f.  Anat.  u.  Physiol.,  1873  and  1876. 
"  Ber.  d.  k.  f^achs.  Gesellscb.  d.  Wissensch.,   Math.-phys.  Klasse,  Bd.  19, 
1867,  and  Centralbl.  f.  d.  med.  Wissensch.,  1867,  S.  356. 
»  Centralbl.  f.  d.  med.  Wissensch.,  1867.  S.  723. 


THE  RESPIRATOR Y  EXCHANGE  OF  GAS.  593 

The  gaseous  excliange  in  the  tissues,  which  has  been  designated 
internal  respiration,  consists  cliiefiy  in  that  the  oxygen  passes  from 
the  blood  in  the  capillaries  to  the  tissues,  while  the  chief  bulk  of  the 
carbon  dioxide  of  the  tissues  originates  therein  and  passes  into  the 
blood  of  the  capillaries.  The  exchange  of  gas  in  the  lungs,  which 
is  called  external  respiration,  consists,  as  we  learn  by  a  comparison 
of  the  inspired  and  expired  air,  iu  the  blood  taking  oxygen  from  the 
air  in  the  lungs  and  giving  off  carbon  dioxide. 

What  kind  of  processes  take  part  in'  this  double  exchange  of 
gas?  Is  the  gaseous  exchange  simply  the  result  of  an  unequal 
tension  of  the  blood  on  one  side  and  the  air  in  the  lungs  or  tissues 
on  the  other  ?  Do  the  gases  pass  from  a  place  of  higher  pressure  to 
one  of  a  lower,  according  to  the  laws  of  diffusion,  or  are  other  forces 
and  processes  active  ? 

These  questions  are  closely  related  to  another  question  as  to 
the  tension  of  the  oxygen  and  carbon  dioxide  in  the  blood  and  in 
the  air  of  the  lungs  and  tissues. 

Oxygen  occurs  in  the  blood  in  a  disproportionately  large  part 
as  oxyhaemoglobin,  and  the  law  of  the  dissociation  of  oxyhaemoglobin 
is  of  fundamental  importance  in  the  study  of  the  tension  of  the 
oxygen  in  the  blood. 

If  we  recall  that,  according-  to  BOHR,  what  we  generally  call  oxyhaemo- 
plobin  is  a  mixture  of  haemoglobins,  which  for  one  and  tlie  same  oxygen 
pressure  can  unite  with  different  quantities  of  oxygen,  and  also,  as  shown  by 
Siegfried,  that  there  exists,  besides  the  oxyhaemoglobin,  another  dissociable 
oxygen  combination  of  haemoglobin,  namelj',  pseudohaemoglobin.  it  seems  that 
we  have  several  important  preliminary  questions  to  solve  before  we  come  to  a 
discussion  of  the  dissociation  conditions  of  oxyhaemoglobin.  As  the  above 
statements  are  iu  part  contradicted  and  in  part  not  sufficiently  proven,  and  as 
also,  according  to  lluFNER,  no  difference  exists  between  a  oxyhaemoglobin 
solution  and  a  solution  of  blood-corpuscles  in  regard  to  its  delivery  of  oxygen, 
we  are  justified  in  setting  the  above  statements  aside  for  the  present  and  only 
taking  up  the  generally  accepted  and  authoritative  assertions. 

For  the  understanding  of  the  laws  by  which  the  oxygen  is  taken 
up  by  the  blood  in  the  alveoli  of  the  lungs  the  investigations  on  the 
dissociation  of  oxyhaemoglobin  are  important,  and  especially  those 
which  relate  to  the  dissociation  at  the  temperature  of  the  body  are 
of  great  physiological  importance.  Several  investigators  have 
experimented  on  this  subject,  especially  (1.  IIufner.'  He  has 
proven  an  important  fact,  namely,  that  a  freshly  j)repared  solu- 
tion of  pure  oxyhaemoglobin  crystals  does  not  act  unlike  freshly 

'  Du  Bois-Keymond's  Arch.,  1890.  Hilfner  here  gives  also  his  older  re- 
fecarches  on  this  subject. 


594  CHEMISTRY  OF  RESPIRATION. 

defibrinated  blood  as  regards  the  dissociation  of  oxyhgemoglobin. 
He  also  showed  that  the  dissociation  is  dependent  upon  the  concen- 
tration, namely,  that  at  a  given  pressure  a  dilate  solution  is  more 
strongly  dissociated  than  a  more  concentrated  solution.  He  found 
for  solutions  containing  14^  oxyhsemoglobin  that  the  dissociation 
at  +  35°  C.  and  an  oxygen  partial  pressure  of  75  mm.  Hg  was 
only  very  insignificant  and  only  little  stronger  than  with  a  partial 
pressure  of  152  mm.  In  the  first  instance  96.89^  of  the  total 
pigment  was  present  as  oxyhsemoglobin  and  3.11^  as  hgemoglobin, 
while  in  the  other  case,  at  152  mm.  pressure,  the  respective  figures 
were  98.42  and  1.58^.  The  dissociation  becomes  stronger  first 
with  an  oxygen  partial  pressure  of  about  75  mm.  Hg  and  down- 
wards, and  a  corresponding  increase  in  the  quantity  of  reduced 
haemoglobin;  but  even  with  an  oxygen  partial  pressure  of  50  mm. 
Hg  the  quantity  of  haemoglobin  was  only  4.6^  of  the  total  pigment. 

From  these  and  older  researches  by  Hufitee  ^  which  were  made 
at  35  or  39°  C.  it  follows  that  the  partial  pressure  of  the  oxygen 
may  be  reduced  to  one  half  of  the  atmospheric  air  without  infiuenc- 
jng  essentially  the  quantity  of  oxygen  in  the  blood  or  a  correspond- 
ing solution  of  oxyh  moglobin.  We  can  also  conclude  from  the 
quantity  of  oxygen  or  oxyhsemoglobin  in  the  arterial  blood  tliat  the 
tension  of  the  oxygen  in  the  arterial  blood  must  be  relatively  higher. 
Based  on  the  investigations  of  several  experimenters,  such  as 
P.  Bert,"  Hertee,'  and  Hufner,  who  experimented  partly  on 
living  animals  and  partly  with  haemoglobin  solutions,  we  generally 
consider  the  tension  of  the  oxygen  in  arterial  blood  at  the  tempera- 
ture of  the  body  equal  to  an  oxygen  partial  pressure  of  75-80 
mm.  Hg. 

We  must  now  compare  these  figures  with  the  tension  of  the 
oxygen  in  the  air  of  the  lungs. 

Numerous  investigations  as  to  the  composition  of  the  inspired 
atmospheric  air  as  well  as  the  expired  air  are  at  hand,  and  we  can 
say  that  these  two  kinds  of  air  at  0°  C.  and  a  pressure  of  760 
mm.  Hg  have  the  following  average  composition  in  volume  per 
cent: 

Oxygen.         Nitrogen.    Carbon  Dioxide. 

Atmospheric  air 20.96  79.02  0.03 

Expired  air 16.03  79.59  4.38 

i  L.  c. 

*  Paul  Bert,  La  pre-sion  barometrique.     Paris,  1878. 

*  Zeitscbr.  f.  pbysiol.  Cbem.,  Bd.  3. 


THE   RESPIRATORY  EXCTlAyUE   OF  GAS.  595 

The  partial  pressure  of  the  oxj'gen  of  the  atmospheric  air  corre- 
sponds at  a  normal  barometric  pressure  of  760  mm.  to  a  pressure 
of  159  mm.  Hg.  The  loss  of  oxygen  which  the  inspired  air 
suffers  in  respiration  amounts  to  about  4.93^^,  while  the  expired  air 
contains  about  one  hundred  times  as  much  carbon  dioxide  as  the 
inspired  air. 

The  expired  air  is  therefore  a  mixture  of  alveolar  air  with  the 
residue  of  "inspired  air  remaining  in  the  air-passages;  hence  in  the 
study  of  the  gaseous  exchange  in  the  lungs  we  must  first  consider 
the  alveolar  air.  We  have  no  direct  determination  of  the  composi- 
tion of  the  alveolar  air,  but  only  approximate  calculations.  From 
the  average  results  found  by  Vierokdt  '  in  normal  respiration  for 
the  carbon  dioxide  in  the  expired  air,  4.03':^,  Zuntz '^  has  calculated 
the  probable  quantity  of  carbon  dioxide  in  the  alveolar  air  as  equal 
to  5.44^.  If  we  start  from  this  value,  with  the  assumption  that 
the  quantity  of  nitrogen  iu  the  alveolar  air  does  not  essentially  differ 
from  the  expired  air,  and  admit  tliat  the  quantity  of  oxygen  in  the 
alveolar  air  is  6^  less  than  the  inspired  air,  we  find  that  the  alveolar 
air  contains  14.96^  oxygen,  corresponding  to  a  partial  pressure  of 
114  mm.  Hg. 

We  have  several  direct  determinations  as  to  the  composition  of 
the  alveolar  air  of  dogs  which  show  that  the  alveolar  air  is  not  much 
richer  in  carbon  dioxide  than  the  expired  air. 

By  means  of  the  lung  catheter,  an  apparatus  constructed  by 
Pfluger,  his  pupils  Wolffberg  '  and  Nussbaum  *  have  investi- 
gated the  composition  of  the  alveolar  air  of  dogs.  By  the  introduc- 
tion of  a  catheter  of  a  special  construction  into  a  branch  of  a 
bronchia  the  corresponding  lobe  of  the  lung  may  be  hermetically 
sealed,  while  in  the  other  lobes  of  the  same  lung  and  in  the  other  luag 
the  ventilation  remains  unhindered,  so  that  no  stowing  of  carbon 
dioxide  takes  place  in  the  blood.  When  the  cutting  off  lasts  so 
long  that  a  complete  equalization  between  the  gases  of  the  blood 
and  the  cut-off  air  of  the  lungs  is  assumed,  a  sample  of  this  air  of 
the  lungs  is  removed  by  means  of  the  catheter  and  analyzed.  In 
the  air  thus  obtained  from  the  lungs  Wolffberg  and  Nussbaum 
found  an  average  of  3.6^  CO^.    Nussbaum  has  also  determined  the 

'  See  ZuNTZ  in  Hermann's  Handbucb,  Bd.  4,  Thl.  2,  S.  105. 
'  Hermann's  Handbucb,  Bd.  4,  Thl.  2,  S.  106. 
»  Pflilger's  Arch.,  Bdd.  5  u.  6. 
♦  Ibid. .  Bd.  7. 


596  GHEMI8TRY  OF  RESPIRATION. 

carbou-dioxide  tension  in  the  blood  from  the  right  heart  in  a  case 
simultaneoas  with  the  catheterization  of  the  lungs.  He  found 
nearly  identical  results,  namely,  a  carbon-dioxide  tension  of  3.84^ 
and  of  3.81^  of  an  atmosphere,  which  also  shows  that  complete- 
equalization  between  the  gases  of  the  blood  and  lungs  in  the  enclosed 
parts  of  the  lungs  had  taken  place.  According  to  these  investiga- 
tions a  considerably  higher  oxygen  partial  pressure  exists  in  the 
alveoli  of  the  lungs  than  in  the  blood,  and  the  taking  up  of  oxygen 
from  the  air  of  the  lungs  is  probably  according  to  the  laws  of 
diffusion. 

According  to  Bohr  '  the  facts  are  otherwise,  and  the  lungs,, 
according  to  him,  are  active  in  the  taking  up  of  oxygen. 

He  experimented  on  dogs,  allowing  the  blood,  whose  coagulation  had  been, 
prevented  by  the  injection  of  peptone  solution  or  infusion  of  the  leech,  to  flow 
from  one  bisected  carotid  to  the  other,  or  from  the  femoral  artery  to  tLie  femoral 
vein,  through  an  apparatus  called  by  him  an  hsemataSrometer.  The  apparatus, 
wh  ch  is  a  modification  of  Ludwig's  rheometer  (stromuhr),  allowed,  according- 
to  BoiiR,  of  a  complete  interchange  between  the  gases  of  the  blood  circulating- 
through  the  apparatus  and  a  quantity  of  gas  whose  composition  was  knowu 
at  the  beginning  of  the  experiment  and  enclosed  in  the  apparatus.  The  mix- 
ture of  gases  was  analyzed  after  an  equalization  of  the  gases  by  diffusion.  In 
this  way  the  tension  of  the  oxygen  and  carbon  dioxide  in  the  circulating  arterial 
blood  was  determined.  During  tlje  experiment  the  composition  of  the  inspired^ 
and  expired  air  was  also  determined,  the  number  of  inspirations  noted,  and  the- 
extent  of  respiratory  exchange  of  gas  measured.  To  be  able  to  compare  be- 
ti\een  the  gas  tension  in  the  blood  and  in  an  expiration  air,  whose  composition 
was  closer  to  the  unknown  composition  of  tlie  alveolar  air  than  the  ordinary 
expired  air,  the  composition  of  the  expired  air  at  the  moment  it  passed  the 
bifurcation  of  the  trachea  was  ascertained  by  special  calculation.  The  tension 
of  the  gases  in  this  "  bifurcated  air"  could  be  compared  with  the  tension  of  th& 
gases  of  the  blood,  and  in  such  a  way  that  the  comparison  in  both  cases  took 
the  same  time. 

Bohr  found  remarkably  high  results  for  the  oxygen  tension  in 
arterial  blood  in  this  series  of  experiments.  They  varied  between 
101  and  144  mm.  Hg  pressure.  In  eight  out  of  nine  experiments- 
on  the  breathing  of  atmospheric  air,  and  in  four  out  of  five  experi- 
ments ou  breathing  air  containing  carbon  dioxide,  the  oxygen 
tension  in  the  arterial  blood  was  higher  than  the  "  bifurcated  air."' 
The  greatest  difference,  where  the  oxygen  tension  was  higher  in  the 
blood  than  in  the  air  of  the  lungs,  was  38  mm.  Hg. 

According  to  Bohr  we  cannot  simply  explain  the  taking  up  of 
oxygen  by  the  blood  from  the  air  of  the  lungs  by  a  higher  partial 
pressure  of  the  oxygen.  The  difference  in  tension  between  the  two> 
sides  of  the  walls  of  the  alveoli  may  therefore,  according  to  him, 
not  be  the  only  force  which  serves  in  the  migration  of  the  oxygen 

1  Skand.  Arch.  f.  Physiol.,  Bd.  2. 


OXYGEN  TENSION  IN  THE  BLOOD.  597 

1;hrongh  tlie  Inng  tissue,  and  the  lungs  themselves  must,  according 
to  Bohr,  exercise  an  unknown  specific  action  in  the  taking  up  of 
■oxygen. 

IIufxer'  has  made  the  objection  to  Bohr's  views  that  in  the 
experimental  conditions  established  by  Bohr  the  equilibrium 
between  the  air  in  the  apparatus  and  the  gases  of  the  blood  had  not 
probably  set  in.  Fredericq"  has  also  come  to  the  same  conclusion 
by  experiments  with  uncoagulable,  living  arterial  dog's  blood, 
allowing  it  to  flow  through  an  aerotonometer-tube  (see  Tension  of 
Carbon  Dioxide),  whereby  a  very  slow  diffusion  equalization  took 
place  between  the  gases  of  the  circulating  blood  and  the  air  enclosed 
in  the  tube.  When  the  original  partial  pressure  of  the  oxygen  in 
the  acirotonometer  atmosphere  was  very  low  or  very  high  the  diffu- 
sion equilibrium  was  not  reached  inside  of  an  hour.  Fredericq 
aXso  found  that  the  oxygen  tension  in  arterial  peptone  blood  of  the 
dog  remained  always  several  per  cent  of  an  atmosphere  below  the 
partial  pressure  of  the  oxygen  in  the  air  of  the  lung  alveoli.  We 
have  therefore  no  sufficient  ground  to  abandon  the  present  generally 
accepted  view,  that  the  oxygen  is  taken  up  in  the  lungs  simply  by 
diffusion. 

As  the  haemoglobin  obtained  from  different  blood  portions  does  not,  accord- 
ing to  Bohr,  always  talie  up  the  same  quantity  of  oxygen  for  each  gramme, 
so,  according  to  him,  tlie  haemoglobin  within  the  blood-corpuscle  may  show  a 
similar  beliavior.  He  calls  the  quantity  of  oxygen  (measured  at  0°  C.  and  760 
miu.  Hg)  which  is  taken  up  by  1  grm.  haemoglobin  of  the  blood  at  15°  C.  and 
an  oxygen  pressure  of  150  mm.  tlie  specific  oxygen  capacity.^  This  quantity, 
according  to  BoiiR,  may  Ije  different  not  only  in  different  individuals, 
but  also  in  the  different  vascular  systems  of  the  same  animal,  and  it  may 
also  be  changed  experimentally  by  bleeding,  breathing  air  deficient  in  oxygen, 
or  poisoning.  It  is  low  evident  that  one  and  the  same  quantity  of  oxygen 
in  the  blood,  other  things  being  equal,  must  have  a  different  tension 
according  to  the  specific  oxygen  capacity  is  greater  or  smaller.  The  tension 
of  the  oxygen  may,  according  to  Dour,  be  changed  without  changing  the 
■quantity  of  oxygen,  and  the  animal  body  must,  according  to  him,  have 
means  of  varying  the  tension  of  the  oxygen  in  the  tissues  in  a  short  time 
without  changing  the  quantity  of  oxygen  contained  in  the  blood.  The  great 
importance  of  such  a  property  of  the  tissues  for  respiration  is  evident ;  but 
it  IS  perhaiis  too  early  to  give  a  positive  opinion  on  Bohr's  statements  and 
experiments. 

It  is  to  be  inferred,  from  the  above  statements  in  regard  to  the 
tension  and  dissociation  of  the  oxygen  of  the  blood,  that  the  quantity 
-of   oxygen   in  the    blood  is   not   essentially  dependent  upon    the 

'  Du  Bois-Reymond's  Arch.,  1890,  S.  10. 
«  Centralbl.  f.  Physiologie,  Bd.  7.  S.  33. 
»  Centralbl.  f.  Physiol.,  Bd.  4,  S.  254. 


598  CHEMISTRY   OF  RESPIRATION. 

quantity  of  oxygen  in  the  air,  at  least  within  certain  limits.  This 
in  fact  is  the  case. 

That  the  raising  of  the  oxygen  pressure,  even  to  a  pressure  of 
one  atmos]3here,  has  no  essential  influence  on  the  quantity  of  oxygen 
taken  up  and  on  the  carbon  dioxide  eliminated,  has  been  known  for 
a  long  time  (Lavoisier,  EEG]srAULT,  and  Reiset').  Further 
experiments  in  this  direction  have  been  made  by  Paul  Bert."  He 
found  that  in  pure  oxygen  at  a  pressure  of  3  atmospheres,  or  in 
ordinary  air  at  a  pressure  of  15  atmospheres,  animals  quickly  died 
with  convulsions.  Before  and  during  the  spasms  a  lowering  of  tem-- 
perature  took  place,  and  the  consumption  of  oxygen,  as  well  as  the 
elimination  of  carbon  dioxide  and  the  combustion  of  the  sngar  of 
the  blood,  was  lowered.  By  raising  the  oxygen  pressure  of  the  air 
to  3  atmospheres  the  quantity  of  oxygen  contained  in  the  blood  is 
somewhat  increased.  It  seems  that  the  quantity  of  oxygen  which 
is  here  taken  up  corresponds  to  that  quantity  which  is  simply 
absorbed  by  the  blood  at  that  pressure. 

It  is  also  of  special  interest  to  know  to  what  extent  the  partial 
pressure  of  the  oxygen  of  the  air  can  be  lowered  without  causing 
any  injurious  action  or  danger  to  life.  A  great  many  observations 
have  been  made  on  this  subject,  partly  on  man  and  partly  on 
animals.  It  follows  from  these  observations  that  this  limit  may 
undergo  considerable  variation.  In  human  beings  it  seems  to  be 
somewhat  higher  than  in  certain  animals,  the  rabbit  for  example. 
P.  Bert  °  found  on  experiments  on  himself  in  diluted  air  that  a  gas 
mixture  with  11.3^  oxygen  caused  serious  disturbance,  Leblanc  ^ 
found  no  difficulty  in  breathing  air  containing  15.3^,  but  with  9.8^ 
ox_ygen  he  felt  dizzy,  nauseated,  and  faint.  The  aeronauts  Sivel 
and  Croce-Spixelli  ^  died  at  an  air-pressure  of  260  mm.  Hg, 
corresponding  to  7.2^  oxygen. 

The  statements  of  Loewt  °  are  of  special  interest  in  regard  to 
breathing  under  diminished  oxygen-pressure.  In  the  person 
experimented  upon  the  minimum  alveolar  oxygen-tension  sufficient 
for  the  normal  processes  of  metabolism  was  equal  to  40-45  mm. 
Hg,  which  according  to  Hufner's  table  corresponds  to  a  mixture 

'  See  Hoppe-Seyler,  Physiol.  Chem.,  S.  545. 

^  La  pression  baroiuetrique.     Paris,  1878. 

3L.  c. 

■*  Cited  from  P.  Bert,  La  pression  barometrique, 

6  Cited  from  Hoppe-Seyler,  Physiol.  Chem.,  S.  9  u.  549. 

«  Pflilger's  Arch.,  Bd.  58. 


REiyPIRATION    WITH  JJJMIMsHEl)    OX^GEIi  PRESSUEE.     599 

of  about  9-1^  oxyhfemoglobin  and  G^  Invmoglobin.  This  minimum 
alveolar  oxjgen-tensiou  may  be  reached,  according  to  Loewy,  with 
different  quantities  of  oxygen  in  the  insjDired  air  by  changing  the 
breathing  mechanisms.  By  greatly  increasing  the  qiiantiby  of 
inspired  air  in  a  unit  of  time,  as  by  a  deeper  inspiration,  the 
alveolar  oxygen-tension  may  remain  constant  or  even  be  increased, 
namely,  on  lowering  the  oxygen-tension.  Thus  Loewy  observed  in 
an  experiment  an  alveolar  oxygen-tension  of  41. "2  mm.  Hg  with 
12.2j^  oxygen  in  the  inspired  air,  6.14  litres  respired  air  per  minute, 
and  292.6  c.  c.  the  volume  of  each  inspiration.  In  two  other 
experiments,  where  the  volume  of  the  respired  air  was  31.4  and  35.9 
litres  per  minute  with  785  and  972  c.  c.  for  every  inspiration,  the 
alveolar  oxygen-tension  was  43.9  and  43.4  mm.,  with  7.522  and 
7.32^  oxygen  in  the  inspired  air.  Lowering  the  alveolar  oxygen- 
tension  to  the  limit  40-45  mm.  caused  no  change  on  the  breathing 
mechanisms  and  did  not  correspondingly  change  the  respiratory 
quotient.  Below  this  limit  the  gaseous  exchange  is  so  changed  that 
the  elimination  of  carbon  dioxide  as  compared  with  the  taking  up 
of  oxygen  increases  and  the  respiratory  quotient  is  correspondingly 
raised. 

In  certain  animals  the  limit  seems  to  be  lower  than  with  human 
beings.  W.  Muller,'  Friedlaxder  and  Herter'  noted  this  in 
rabbits.  With  7-ofc  oxygen  in  the  inspired  air  a  strong  dyspnoea 
occurred  in  the  experiments  of  Friedlander  and  Herter,  but  the 
animal,  which  breathed  under  a  large  receiver,  did  not  die  until  l|-2 
hours  after  the  quantity  of  oxygen  had  sunk  to  2.1-3.8^.  Hoppe- 
Seyler  and  Strogaxow  '  found  that  in  dogs  the  respiratory  move- 
ment stopped  when  the  quantity  of  oxygen  in  the  respired  air  had 
sunk  to  3.542,^^,  and  Bert  found  in  experiments  on  different 
animals,  including  frogs  and  birds,  that  death  occurred  when  the 
quantity  of  oxygen  was  from  1.3  (in  frogs)  to  4.4^. 

In  regard  to  the  quantity  of  oxygen  in  the  blood  at  lower  air- 
pressures,  the  observations  of  Fraxkel  and  Geppert^  on  dogs 
must  be  mentioned.  At  an  air-pressure  of  410  mm.  mercury  the 
quantity  of  oxygen  in  the  arterial  blood  was  normal;  at  an  air- 

'  Wien.     Sitzungsber.,  Bd.  33,  and  Annal.  d.  Cliem.  u.  Pharm.,  Bd.  108. 
«  Zeitscbr.  f.  pbysiol.  Chem.,  Bd.  3. 
*  Ptiliger's  Arch  ,  Bd.  12. 

■»  Ueber  die  Wirkungen  der  verdiinnten  Luft  auf  den  Orgauismus.  Berlin, 
.1883 


^600  CHEMISTRY   OF  RESPIRATION. 

pressure  of  378-365  mm.  it  was  a  little  diminished,  and  only  at  a 
lowering  of  the  pressure  to  300  mm.  was  a  considerable  decrease  of 
the  oxygen  observed. 

The  question  how  it  is  possible  for  man  and  animals  to  live  for 
any  length  of  time  in  high  altitudes  with  a  diminished  oxygen 
pressure  is  important  in  this  connection.  In  this  regard  Viault  ^ 
has  called  attention  to  the  fact  that  the  number  of  blood-corpuscles 
is  greater  in  such  individuals.  Thus  the  llama,  according  to  him, 
lias  about  16  million  blood-corpuscles  per  cubic  millimetre.  By 
observations  on  himself  and  other  persons,  as  well  as  on  animals, 
ViAULT  found  the  first  effect  of  living  in  high  altitudes  is  a  con- 
siderable increase  in  the  number  of  red  cor^Duscles,  which  in  his 
own  case  amounted  to  5-8  million.  The  quantity  of  hsemoglobin  is 
on  the  contrary,  according  to  Viault,  increased  only  in  narrow 
limits  on  living  for  some  time  in  the  mountains,  but  the  hsemo- 
globin is  divided  among  so  many  more  blood-corpuscles,  and  there- 
fore a  much  greater  surface  comes  in  contact  with  oxygen.  Con- 
trary to  the  statement  of  Viault,  Muntz^  has  found  that  among 
the  above-mentioned  conditions  a  considerable  increase  in  the  quan- 
tity of  iron  and  hsemoglobin  in  the  blood  takes  place.  Egger  ' 
iound  among  the  influences  of  high  climates  a  considerable  increase 
in  the  number  of  blood-corpuscles  as  well  as  in  the  quantity  of 
haemoglobin,  while  Koeppe,^  on  the  contrary,  observed  a  diminution 
•of  the  latter  besides  a  great  increase  in  the  number  of  blood-cor- 
puscles. Regxard  ^  has  observed  a  considerable  increase  in  the 
quantity  of  hsemoglobin  in  a  guinea-pig  which  was  enclosed  in  a 
receiver  for  a  whole  month  with  a  diminution  of  pressure  corre- 
sponding to  a  height  of  3000  metres. 

The  tension  of  the  carbon  dioxide  in  the  blood  has  been 
determined  in  different  ways  by  Pfluger  and  his  pupils,  Wolff- 
berg,'  Strassburg,^  and  Nussbaum."  According  to  the  aerotono- 
metric  method  the  blood  is  allowed  to  flow  directly  from  the  artery 

'  Compt.  rend.,  Tomes  111,  112  et  114. 
^  Compt.  rend.,  Tome  112. 
'  Cited  from  Maly's  Jaliresber. ,  Bd.  23. 
*  Iljid.,  Bd.  23. 

^  Coinpt.  rend.  Soc.  de  Biol.,  1892.  Cited  from  Centralbl.  f.  Phjsiologie, 
Bd.  7,  1^93. 

6  Pflilger's  Arcb.,  Bd.  6. 
'  Ibid.,  Bri.  6.     . 
«7Wd,  Bd.  7. 


CARBON  DIOXIDE  TENSION  IN  THE  BLOOD.  fiOl 

or  vein  through  a  glass  tube  which  contains  a  gas  mixture  of  a  known 
composition  If  the  tension  of  the  carbon  dioxide  in  the  blood  is 
greater  than  the  gas  mixtare,  then  the  blood  gives  up  carbon 
dioxide,  while  in  the  reverse  case  it  takes  up  carbon  dioxide  ftom 
the  gas  mixture.  The  analysis  of  the  gas  mixture  after  passing  the 
blood  through  it  will  also  decide  if  the  tension  of  the  carbon  dioxide 
in  the  blood  is  greater  or  less  than  in  the  gas  mixtare;  and  by  a 
suflEiciently  great  number  of  determinations,  especially  when  the 
quantity  of  carbon  dioxide  of  the  gas  mixtare  corresponds  as  nearly 
as  possible  in  the  beginning  to  the  pi-obable  tension  of  this  gas  in  the 
blood,  we  may  learn  the  tension  of  the  carbon  dioxide  in  the  blood. 

According  to  this  method  the  carbon-dioxide  tension  of  the 
arterial  blood  is  on  an  average  2.8^  of  an  atmosphere,  corresponding 
to  a  pressure  of  '11  mm.  mercury  (Steassburg ').  In  the  blood 
from  the  pulmonary  alveoli  Xussbaum  "^  found  a  carbon-dioxide 
tension  of  o.Sl^  of  an  atmosphere,  corresponding  to  a  pressure  of 
•28.95  mm.  mercary.  Strassburg,  who  experimented  on  tracheot- 
omized  dogs  in  which  the  ventilation  of  the  lungs  was  less  active 
and  therefore  the  carbon  dioxide  was  removed  from  the  blood  with 
less  readiness,  found  in  the  venous  blood  of  the  heart  a  carbon- 
dioxide  tension  of  oA^c  of  an  atmosi^here,  corresponding  to  a  partial 
pressure  of  -il.Ol  mm.  mercury. 

Another  method  is  the  catheterization  of  a  lobe  of  the  lungs 
(see  page  b^b).  In  the  air  thus  obtained  from  the  lungs  Nussbaum 
and  WoLFFBERG  found  an  average  of  3.6,^  CO,.  Nussbaum,  as 
previously  mentioned,  has  also  determined  the  carbon-dioxide 
tension  in  the  blood  of  the  pulmonary  alveoli  in  a  case  simultaneous 
with  the  catheterization  of  the  lungs.  He  found  nearly  identical 
results,  namely,  a  carbon-dioxide  tension  of  3.8-4^^  and  3,81;^. 

Bohr  in  his  exj^eriments  above  mentioned  (page  596)  has 
arrived  at  other  results  in  regard  to  the  carbon-dioxide  tension.  In 
eleven  experiments  with  inhalation  of  atmospheric  air  the  carbon- 
dioxide  tension  in  the  arterial  blood  varied  from  0  to  38  mm.  Hg,  and 
in  five  experiments  with  inhalation  of  air  containing  carbon  dioxide 
from  0.9  to  57,8  mm,  Hg,  A  comparison  of  the  carbon-dioxide 
tension  in  the  blood  with  the  bifurcated  air  gave  in  several  cases 
a  greater  carbon-dioxide  pressure  in  the  air  of  the  lungs  than  in  the 
blood,  and  as  maximum  this  difference  amounted  to  17.2  mm.  in 
favor  of  the  air  of  the  lungs  in  the  experiments  with  inhalation  of 
'  L.  c.  »  L.  c. 


602  CHEMISTRY   OF  RESPIRATION. 

atmospheric  air.  As  the  alveolar  air  is  richer  in  carbon  dioxide 
than  the  bifurcated  air,  this  experiment  unquestionably  proves, 
according  to  Bohr,  that  the  carbon  dioxide  has  migrated  against 
the  high  pressure. 

In  opposition  to  these  investigations,  Fredericq  ^  in  his  above- 
mentioned  experiments,  obtained  the  same  figures  for  the  carbon- 
dioxide  tension  in  arterial  peptone  blood  as  Pfluger  and  his  pupils 
found  for  normal  blood.  The  low  figures  obtained  by  Bohr  for  the 
carbon-dioxide  tension  appear  remarkable  when  we  recall  that 
GrRANDis '  found  in  peptone  blood  which  Lahousse  '  and  Blach- 
STEIN  ^  had  shown  was  poor  in  carbon  dioxide  a  high  carbon-dioxide 
tension. 

A  certain  importance  has  been  ascribed  to  oxygen  in  regard  to 
the  elimination  of  carbon  dioxide  in  the  lungs,  in  that  it  has  an 
expelling  action  on  the  carbon  dioxide  from  its  combinations  in  the 
blood.  This  statement,  first  made  by  Holmgren,^  has  recently 
found  an  advocate  in  Werigo.^  This  investigator  has  made 
ingenious  experiments  on  living  animals  in  which  he  allows  both 
lungs  of  the  animal  to  breathe  separately,  the  one  with  hydrogen  and 
the  other  with  pure  oxygen  or  a  gas  mixture  rich  in  oxygen.  He 
invariably  found  a  greater  carbon-dioxide  tension  in  the  air  sucked 
from  the  lungs  in  the  presence  of  oxygen,  and  he  draws  the  con- 
clusion from  his  experiments  that  the  oxygen  passing  from  the  lung 
alveoli  into  the  blood  raises  the  carbon-dioxide  tension.  According 
to  Werigo,  by  this  action  the  oxygen  is  a  powerful  factor  in  the 
elimination  of  carbon  dioxide,  and  therefore  it  is  not  necessary  to 
assume  a  specific  action  of  the  lung  itself  in  these  processes. 

ZuNTZ  '  has  suggested  important  objections  to  the  investigations 
of  Werigo,  but  they  have  not  been  substantiated  by  experiment  j 
hence  the  question  is  still  open. 

Also  in  regard  to  the  elimination  of  carbon  dioxide  in  the  lungs 
we  have  no  striking  reason  for  abandoning  the  common  view  that 
the  carbovi  dioxide  simply  passes  from  the  blood  into  the  air  of  the 
lungs  according  to  the  laws  of  diffusion. 

»  Centralbl.  f.  Physiol.,  Bd.  7. 

»  Du  Bois-Reymond's  Arch.,  1891,  S.  499. 

3  Ibid.,  1889,  S.  77. 

*/6^•c^.,  1891,  S.  894. 

^  Wien.  Sitzungsber. ,  Math.-nat.  Klasse,  Bd.  48. 

«  Pfl tiger's  Arch.,  Bdd.  51  u.  53. 

^  Ibid.,  Bd.  53. 


INTERNAL  RESPIRATION.  603 

From  what  has  been  said  above  (page  593)  in  regard  to  the 
internal  respiration  we  derive  that  it  consists  chiefly  in  that  in  the 
capillaries  the  oxygen  passes  from  the  blood  into  the  tissues,  while 
the  carbon  dioxide  passes  from  the  tissues  into  the  blood. 

The  assertion  of  Estor  and  Saikt  Pierre  '  that  the  quantity 
of  oxygen  in  the  blood  of  the  arteries  decreases  with  the  remoteness 
from  the  heart  has  been  shown  as  incorrect  by  PrLiJGER/  and  the 
oxygen  tension  in  the  blood  on  entering  the  capillaries  must  be 
higher.  As  compared  with  the  capillaries  the  tissues  are  to  be  con- 
sidered as  nearly  or  entirely  free  from  oxygen,  and  in  regard  to  the 
oxygen  a  considerable  difference  in  pressure  must  exist  between  the 
blood  and  tissues.  The  possibility  that  this  difference  in  pressure 
is  sufficient  to  supply  the  tissues  with  the  necessary  quantity  of 
oxygen  is  hardly  to  be  doubted. 

In  regard  to  the  carbon-dioxide  tension  in  the  tissue  we  must 
assume  a  priori  that  it  is  higher  than  in  the  blood.  This  is  found 
to  be  true.  Strassburg  '  found  in  the  urine  of  dogs  and  in  the 
bile  a  carbon-dioxide  tension  of  9^  and  7j^  ot  an  atmosphere, 
respectively.  The  same  experimenter  has,  further,  injected  atmos- 
pheric air  into  a  ligatured  portion  of  the  intestine  of  a  living  dog 
and  analyzed  the  air  taken  out  after  some  time.  He  found  a 
carbon-dioxide  tension  of  7.7^  of  an  atmosphere.  The  carbon- 
dioxide  tension  in  the  tissues  is  considerably  greater  than  iu  the 
venous  blood,  and  there  is  no  objection  to  the  view  that  the  carbon 
dioxide  simply  diffuses  from  the  tissues  to  the  blood  according  to 
the  laws  of  diffusion. 


That  a  true  secretion  of  gases  occurs  in  animals  follows  from  the  composi- 
tion and  behavior  of  the  gases  in  the  svvimminij-bladder  of  fishes.  These 
gases  consist  of  oxygen  and  nitrogen  with  only  small  quantities  of  carbon 
dioxide.  In  fishes  which  do  not  live  at  any  great  depth  the  quantity  of  oxygen 
is  ordinarily  as  high  as  in  the  atmosphere,  while  tishes  whicli  live  at  great 
depths  may,  according  to  BiOT  and  others,*  contain  considerably  more  oxy- 
gen and  even  above  80^.  MoREAXJ^has  also  found  that  after  emptying  tiie 
swimming-bladder  by  means  of  a  trocar  new  air  collected  after  a  time,  and  this 
air  wns  richer  in  oxygen  than  the  atmosplie\ic  air  and  contained  even  85$? 
oxN'gen.  Bohr,'  who  has  proved  and  confirmed  these  statements,  also  found 
that  this  collection  is  under  the  influence  of  the  nervous  system,  because  on 

'  Journ.  de  I'anat.  de  la  physiol.,  Tome  2,  1865. 

'  Pfliiger's  Arch.,  Bd.  1.  , 

3  Pfliiger's  Arch.,  Bd.  6. 

*  See  Hermann's  Ilandb.,  Bd.  4,  Thl.  2,  S.  151. 
'  Compt.  rend.,  Tome  57,  S.  37  u.  816. 

'  Journ.  of  Physiol,,  Vol.  15.  See  also  Hufner,  Du  Bois-Reymond's  Arch., 
1892. 


604:  CHEMISTRY  OF  RESPIBATION. 

the  section  of  certain  branches  of  pneumopfastric  nerve  it  is  discontinued.     It 
is  beyond  dispute  that  we  have  here  a  secretion  and  not  a  difEusion  of  oxygen. 

Several  methods  have  been  suggested  for  the  study  of  the 
quantitative  relationship  of  the  respiratory  exchange  of  gas.  We 
must  refer  the  reader  to  other  text-books  for  more  details  of  these 
methods,  and  we  will  only  here  mention  the  chief  traits  of  the  most 
important  methods. 

'Regnattlt  and  Reiset's  Metliod.  According  to  this  method  the  animal  or 
person  experimented  upon  is  allowed  to  breathe  in  an  enclosed  space.  The  car- 
boo  dioxide  is  removed  from  the  air,  as  it  forms,  by  strong  caustic  alkali,  from 
which  the  quantity  may  be  determined,  while  the  oxygen  is  replaced  continu- 
ally by  exactly  measured  quantities.  This  method,  which  also  makes  possible 
a  direct  determination  of  the  oxygen  used  as  well  as  the  carbon  dioxide  pro- 
duced, has  since  been  modified  by  other  investigators,  such  as  Pfluger  and 
his  pupils,  Seegen  and  NowAK,  and  Hoppe-Sevlek.^ 

Pettenkofer's  Method}  According  to  this  method  the  individual  to  be 
experimented  upon  breathes  in  a  room  through  which  a  current  of  atmospheric 
air  is  pas^sed.  The  quantity  of  air  passed  through  is  carefully  measured.  As 
it  is  impossible  to  analyze  all  the  air  made  to  pass  through  the  chamber,  a 
small  fraction  of  this  air  is  diverted  into  a  branch  line  during  the  entire 
experiment,  carefully  measured,  and  the  quantity  of  carbon  dioxide  and  water 
determined.  From  the  composition  of  this  air  the  quantity  of  water  and  carbon 
dioxide  contained  in  the  large  quantity  of  air  made  to  pass  through  the  cham- 
ber can  be  calculated.  The  consumption  of  oxygen  cannot  be  directly  deter- 
mined in  this  method,  but  may  be  indirectly  by  difference,  which  is  a  defect 
in  this  method. 

Speck's  Method}  For  briefer  experiments  on  man  Speck  has  used  the 
following:  He  breathes  into  two  spirometer  receivers  on  which  the  gas  volume 
can  be  read  ofE  very  accurately,  through  a  mouthpiece  with  two  valves, 
closing  the  nose  with  a  clamp.  The  air  from  one  of  the  spirometers  is  inhaled 
through  one  valve,  and  the  expired  air  passes  through  the  other  into  the  other 
spirometer.  By  means  of  a  rubber  tube  connected  with  the  expiration  tube 
an  accurately  measured  part  of  the  expired  air  may  be  passed  into  an  ab- 
sorption tuiie  and  analyzed. 

ZuNTZ  and  Geppert's  Method}  This  method,  which  has  been  improve  1 
by  ZuNTZ  and  his  pupils  from  time  to  time,  consists  in  the  following:  The 
individual  being  expe  imented  upon  inspires  pure  atmospheric  air  through  a 
very  wide  feed-pipe  leading  from  the  open  air,  the  inspired  and  the  expired 
air  being  separated  by  two  valves  (human  subjects  breathe  with  closed  nose 
by  means  of  a  soft  rubber  mouthpiece,  animals  through  an  air-tight  tracheal 
canula).  The  volume  of  the  expired  air  is  measured  by  a  gas-meter,  and  an 
aliquot  part  of  this  air  collected  and  the  quantity  of  carbon  dioxide  and  oxygen 
determined.  As  the  composition  of  the  atmospheric  air  can  be  considered  as 
constant  within  a  certain  limit,  the  production  of  carbon  dioxide  as  well  as  the 
consumption  of  oxygen  may  be  readily  calculated  (see  the  works  of  Zuntz  and 
his  pupils). 

Hanriot  and  Richet's  method  ^  is  characterized  by  its  simplicity.     These 

1  In  regard  to  this  method  see  Zuntz  in  Hermann's  Handb.,  Bd.  4,  Thl.  2, 
and  Hoppe-Seyler  in  Zeitschr.  f.  physiol.  Chem.,  Bd.  19. 

»  See  Zuntz,  1.  c. 

*  Speck,  Physiologic  des  menschlichen  Athmens.     Leipzig,  1892. 

••  Pfltiger's  Arch.,  Bd.  42.  See  also  Magnus-Levy  in  Pflilger's  Arch.,  Bd.  55, 
S.  10,  in  which  the  work  of  Zuntz  and  his  pupils  is  cited. 

^  Compt.  rend..  Tome  104. 


LUNGS  AND   THEIR  EXPEOTORATIOXS.  Ct05 

investigators  allow  the  total  air  to  pass  tbrougb  three  gas-meters,  one  after  the 
other.  The  first  measures  the  inspired  air,  whose  composition  is  known.  The 
.second  gas-meter  measures  the  expired  air,  and  the  third  the  quantity  ol'  the 
expired  air  after  the  carbon  dioxide  has  been  removed  by  a  suitable  appa- 
ratus. TLe  quantity  of  carbon  dioxide  produced  and  tlie  oxygen  consumed 
can  be  readily  calculated  from  these  data. 


Appendix. 

The  Lungs  and  their  Expectorations. 

Besides  jjroteid  bodies  and  the  albuminoids  of  the  connective 
substance  group,  lecithin,  taurin  (especially  in  ox-lungs),  uric  acid^ 
and  inosit  have  been  found  in  the  Inngs.  Poulet  '  claims  to  have 
found  a  special  acid,  which  he  has  called  puhnotartaric  acid,  in  the 
lung  tissue.  Glycogen  occurs  abundantly  in  the  embryonic  lung, 
but  is  absent  in  the  adult  lung. 

The  black  or  dark  brown  pigment  in  the  lungs  of  human  beings  and 
domestic  animals  consists  chiefly  of  carbon,  which  originates  from  the  soot  in 
the  air.  The  pigment  may  in  part  also  consist  of  melanin.  Besides  carbon, 
other  bodies,  such  as  iron  oxide,  silicic  acid,  and  clay,  may  be  deposited  in  the 
lungs,  being  inhaled  as  dust. 

Among  the  bodies  found  in  the  lungs  under  pathological  condi- 
tions we  must  specially  mention  albumoses  and  peptones  (in  pneu- 
monia and  suppuration),  glycogen,  a  faintly  dextrorotatory 
carbohydrate  differing  from  glycogen  found  by  Pouchet'  in 
consumptives,  and  finally  also  cellulose,  which,  according  to 
Freuxd,'  occurs  in  the  lungs,  blood,  and  pus  of  persons  with 
tuberculosis. 

C,  W.  Schmidt  '  found  in  1000  grms.  mineral  bodies  from  the 
normal  human  lung  the  following:  XaCl  130,  K^O  13,  Na^O  195, 
CaO  19,  MgO  19,  Fe^O,  32,  P,0,  485,  SO3  8,  and  sand  134  grms. 
According  to  Oidtmann  ''  the  kings  of  a  14-day-old  child  contained 
796.05  p.  m.  water,  198.19  p.  m.  organic  bodies,  and  5.76  p.  m. 
inorganic  bodies. 

The  expectoration  is  a  mixture  of  the  mucous  secretion  of  the 
respiratory  passages,  of  saliva  and  buccal  mucus.  Because  of  this 
its  composition  is  very  variable,  especially  under  pathological  con- 

'  Cited  from  Maly's  Jahresber.,  Bd.  18,  S.  348. 

*  Compt.  rend.,  Bd.  96. 

3  Wien.  med.  Jahrb.,  1886.     Cited  from  Maly's  Jahresber.,  Bd.  16,  S.  471. 

*  Cited  from  v.  Gorup-Besanez,  Lehrbuch,  4.  Aufl.,  S.  727. 
« Ibid. ,  S.  732. 


606  CHEMI8TBT  OF  RESPIRATION. 

ditions  when  various  products  mix  with  it.  The  chemical  constit- 
uents are,  besides  the  mineral  substances,  chiefly  mucin  with  a  little 
proteid  and  nuclein  substance.  Under  pathological  conditions 
albumoses  and  peptones,  volatile  fatty  acids,  glycogen,  Charcot's 
crystals,  and  also  crystals  of  cholesterin,  haematoidin,  tyrosin,  fat, 
and  fatty  acids,  triple  phosphates,  etc.,  have  been  found. 

The  form  constituents  are,  under '  physiological  circumstances, 
epithelium-cells  of  various  kinds,  leucocytes,  sometimes  also  red 
blood-corpuscles  and  various  kinds  of  fungi.  In  pathological  con- 
ditions elastic  fibres,  spiral  formations  consisting  of  a  mucin-like 
substance,  fibrin  coagulum,  pus,  pathogenic  microbes  of  various 
kinds,  and  the  above-mentioned  crystals  occur. 


CHAPTER  XVIII. 

METABOLISM'    WITH    VARIOUS   FOODS,    AND    THE    DEMAND    FOR 

FOOD  IN  MAN. 

The  conversion  of  chemical  tension  into  living  energy,  which 
characterizes  animal  life,  leads,  as  previously  stated  in  Cliapter  I, 
to  the  formation  of  relatively  simple  compounds — carbon  dioxide, 
urea,  etc. — which  leave  the  organism,  and  which,  moreover,  being 
very  poor  in  potential  energy,  are  for  this  reason  of  no  or  very  little 
value  for  the  body.  It  is  therefore  absolutely  necessary  for  the  con- 
tinuance of  life  and  the  normal  course  of  the  functions  of  the  body 
that  the  organism  and  its  different  tissues  should  be  supplied  with 
new  material  to  replace  that  which  has  been  exhausted.  This  is 
accomplished  by  means  of  food.  Those  bodies  are  designated  as 
food  which  have  no  injurious  action  upon  the  organism  and  which 
replace  those  constituents  of  the  body  that  have  been  consumed  in 
metabolism  or  that  can  prevent  or  diminish  the  consumption  of 
such  constituents. 

Among  the  numerous  dissimilar  substances  which  man  and  ani- 
mals take  with  the  food  all  cannot  be  equally  uecessary  or  have  the 
same  value.  Some  perhaps  are  unnecessary,  while  others  may  be 
indispensable.  We  have  learned  by  direct  observation  and  a  wide 
experience  that  besides  the  oxygen,  which  is  necessary  for  oxida- 
tion, the  essential  foods  for  animals  in  general,  and  for  man  espe- 
cially, are  water,  mineral  bodies,  profeids,  carbohydrates,  and  fats. 

It  is  also  apparent  that  the  various  groups  of  food-stuffs  neces- 
sary for  the  tissues  and  organs  must  be  of  different  importance  ; 
thus,  for  instance,  water  and  the  mineral  bodies  have  another  value 
than  the  organic  foods,  and  these  again  must  vary  in  importance 

'  The  translator  will  use  in  the  following  pages  for  the  German  word 
"  Stoffwechsel"  Dr.  Burdon-Sanderson's  translation  (Syllabus  of  Lectures, 
1879),  exchange  of  material,  and  at  the  same  time  the  more  general  term 
"  metabolism." 

607 


608  METABOLISM. 

among  themselves.  The  knowledge  of  the  action  of  various  nutri- 
tive bodies  on  the  exchange  of  material  from  a  qualitative  as  well 
as  a  quantitative  point  of  view  must  be  of  fundamental  importance 
in  determining  the  value  of  different  nutritive  substances  relative 
to  the  demands  of  the  body  for  food  under  various  conditions  and 
also  in  deciding  many  other  questions — for  instance,  the  proper 
nutrition  for  an  individual  in  health  and  in  disease. 

Such  knowledge  can  only  be  attained  by  a  series  of  systematic 
and  thorough  observations,  in  which  the  quantity  of  nutritive  ma- 
terial, relative  to  the  weight  of  the  body,  taken  and  absorbed  in  a 
given  time  is  compared  with  the  quantity  of  final  metabolic  products 
which  leave  the  organism  at  the  same  time.  Eesearches  of  this 
kind  have  been  made  by  several  investigators,  but  above  all  should 
be  mentioned  those  made  by  Bischoff  and  Voit,  by  Pettenkofer 
and  Voit,  and  by  Voit  and  his  pupils. 

It  is  absolutely  necessary  in  researches  on  the  exchange  of 
material  to  be  able  to  collect,  analyze,  and  quantitatively  estimate 
the  excreta  of  tlie  organism,  so  that  tliey  may  be  compared  with  the 
quantity  and  composition  of  the  nutritive  bodies  taken  up.  In  the 
first  place,  one  must  know  what  the  habitual  excreta  of  the  body 
are  and  in  what  way  these  bodies  leave  the  organism.  One  must 
also  have  trustworthy  methods  for  the  quantitative  estimation  of 
the  same. 

The  organism  may,  under  physiological  conditions,  be  exposed 
to  accidental  or  periodic  losses  of  valuable  material — such  losses  as 
only  occur  in  certain  individuals,  or  in  the  same  individual  only  at 
a  certain  period  ;  for  instance,  the  secretion  of  milk,  the  production 
of  eggs,  the  ejection  of  semen  or  menstrual  blood.  It  is  therefore 
apparent  that  these  losses  can  only  be  the  subject  of  investigation 
and  estimation  in  special  cases. 

The  regular  and  constant  excreta  of  the  organism  are  of  the  very 
greatest  importance  in  the  study  of  metabolism.  To  these  belong, 
in  the  first  place,  the  true  final  metabolic  products — carbok  diox- 
ide, UREA  (uric  acid,  hippuric  acid,  creatinin,  and  other  urinary 
constituents),  and  a  part  of  the  water.  The  remainder  of  the 
water,  the  mineral  bodies,  and  those  secretions  or  tissue-constituents 

— MUCUS,  DIGESTIVE  FLUIDS,  SEBUM,  SWEAT,  and  EPIDERMIS  FOR- 
MATIONS— which  are  either  poured  into  the  intestinal  tract,  or  se- 
creted from  the  surface  of  the  body,  or  broken  off  and  thereby  lost 
for  the  body,  also  belong  to  the  constant  excreta. 


EXCRETA    OF   THE  ANIMAL    BODY.  609 

The  remains  of  food,  sometimes  indigestible,  sometimes  digest- 
ible but  not  acted  upon,  contained  in  the  faeces,  which  vary  con- 
siderably in  quantity  and  composition  with  the  nature  of  the  food, 
also  belong  to  the  excreta  of  the  organism.  Even  though  these 
remains,  which  are  never  absorbed  and  therefore  are  never  consti- 
tuents of  the  animal  fluids  or  tissues,  cannot  be  considered  as 
excreta  of  the  body  in  a  strict  sense,  still  tlieir  quantitative  esti- 
mation is  absolutely  necessary  in  certain  experiments  on  the 
exchange  of  material. 

The  determination  of  the  constant  loss  is  in  some  cases  accom- 
panied with  the  greatest  difficulties.  The  loss  from  the  detached 
epidermis,  from  the  secretion  of  the  sebaceous  glands,  etc.,  cannot 
be  determined  with  exactness  without  difficulty,  and  therefore — as 
they  do  not  occasion  any  mentionable  loss  because  of  their  small 
quantity — they  need  not  be  considered  in  quantitative  experiments 
on  metabolism.  This  also  applies  to  the  constituents  of  the  mucus, 
bile,  pancreatic  and  intestinal  jitices,  etc.,  occurring  in  the  contents 
of  the  intestine,  and  which,  leaving  the  body  with  the  fjBces,  cannot 
be  separated  from  the  other  contents  of  the  intestine  and  therefore 
cannot  be  quantitatively  determined  separately.  The  uncertainty 
which,  because  of  the  intimated  difficulties,  attaches  itself  to  the 
results  of  the  experiments  is  very  small  as  compared  to  the  variation 
which  is  caused  by  different  individualities,  different  modes  of  liv- 
ing, different  foods,  etc.  Xo  general  but  only  aj^proximate  values 
can  therefore  be  given  for  the  constant  excreta  of  the  human  body. 

The  following  figures  represent  the  quantity  of  excreta  for  24 
hours  of  a  grown  man  weighing  60-70  kilos  on  a  mixed  diet.  The 
numbers  are  compiled  from  the  results  of  different  investigators. 

Qramnips. 

Water 2o0()-8o00 

Salts  (with  the  urine) 20-80 

Carbon  dioxide 750-900 

Urea  20-40 

Other  nitroprenous  urinary  constituents 2-5 

Solids  iu  the  excrements 30-50 

These  total  excreta  are  approximately  divided  among  the  various 
excretions  in  the  following  way — but  still  it  must  not  be  forgotten 
that  this  division  may  vary  to  a  great  extent  under  various  external 
circumstances:  by  respiration  about  32$^,  by  the  evaporation" 
FROM  THE  SKix  17^,  with  the  URINE  46-47^,  and  with  the  excre- 
ments 5-9'^.  Tlie  elimination  by  the  skin  and  lungs,  which  is 
sometimes  differentiated  bv  the  name  "  perspiratio  insensibtlis  *' 


610  METABOLISM. 

from  the  visible  elimination  by  the  kidneys  and  intestine,  is  on  an 
average  about  50^  of  the  total  elimination.  This  proportion,  only 
quoted  relatively,  is  subject  to  considerable  variation,  because  of 
the  great  difference  in  the  loss  of  water  through  the  skin  and  kid- 
neys under  different  circumstances. 

About  90^  of  the  water  in  carnivora  is  excreted  through  the 
kidneys.  In  herbivora  60^  of  the  water  is  eliminated  by  the  ex- 
crements, which  are  30-50^  of  the  total  excreta.  In  man  only  a 
smaller  fraction  of  the  water  (about  5^)  is  eliminated  with  the 
faeces,  and  the  great  mass  of  the  water  is  divided  between  the  kid- 
neys, lungs,  and  skin. 

The  nitrogenous  constituents  of  the  excretions  consist  chiefly  of 
urea,  or  uric  acid  in  certain  animals,  and  the  other  nitrogenous 
urinary  constituents.  A  disproportionally  large  part  of  the  nitrogen 
leaves  the  body  with  the  urine,  and,  as  the  nitrogenous  constitu- 
ents of  this  excretion  are  final  products  of  the  metabolism  of  pro- 
teids  in  the  organism,  the  quantity  of  proteids  transformed  in  the 
body  may  be  easily  calculated  by  multiplying  the  quantity  of 
nitrogen  in  the  urine  by  the  coefficient  6.35  {^^^-  =  6.25),  if  we 
admit  that  the  proteids  contain  in  round  numbers  16^  nitrogen. 

Still  another  question  is  whether  the  nitrogen  leaves  the  body 
only  with  the  urine  or  by  other  channels.  This  last  is  habitually 
the  case.  The  discharges  from  the  intestine  always  contain  some 
nitrogen  which  has  a  twofold  origin.  A  part  of  this  nitrogen  de- 
pends upon  undigested  or  non-absorbed  remnants  of  food,  and 
another  part  on  the  non-absorbed  remains  of  digestive  secretions — 
bile,  pancreatic  Juice,  intestinal  mucus — and  of  epithelium -cells  of 
the  mucous  membrane.  It  follows  that  a  part  of  the  nitrogen  of 
fseces  has  this  last-mentioned  origin  from  the  fact  that  discharges 
from  the  intestine  occur  also  in  complete  inanition. 

If  the  question  to  be  decided  is,  how  much  of  the  nitrogenous 
bodies  is  assimilated  in  certain  modes  of  nutrition  or  after  taking  a 
certain  quantity  of  food,  then  naturally  the  quantity  of  nitrogen 
originating  from  the  food  and  leaving  the  body  with  the  excre- 
ments must  be  subtracted  from  the  total  quantity  of  nitrogen  taken 
up  with  the  food.  To  obtain  the  quantity  of  nitrogen  leaving  the 
body  with  the  excrements  it  is  necessary  to  subtract  from  the  total 
quantity  of  nitrogen  of  the  excrements  the  quantity  of  nitrogen 
coming  from  the  digestive  tract  itself  and  its  secretions,  and  the 
amount  of  this  last  must  be  known. 


ELIMINATION  OF  NITROGEN.  611 

It  is  obvious  that  exact  results  which  answer  for  all  times  can- 
not be  given  for  that  part  of  the  nitrogen  which  has  its  origin  in 
the  digestive  canal  and  fluids.  It  may  not  only  vary  in  different 
individuals,  but  also  in  the  same  individual  after  more  or  less  active 
secretion  and  absorption.  In  the  attempts  made  to  determine  this 
part  of  the  nitrogen  of  tlie  excrements  it  has  been  found  that  in 
man,  on  non-nitrogenous  or  nearly  nitrogen-free  food,  it  amounts 
in  round  numbers  to  somewhat  less  than  1  grm.  per  24  hours 
(RiEDER,*  RuBNER.^)  During  starvation,  in  which  a  smaller 
quantity  of  digestive  secretions  is  eliminated,  it  is  less.  Muller' 
found  in  his  observations  on  tlie  faster  Cetti  that  only  0.2  grm. 
nitrogen  was  derived  from  the  intestinal  canal. 

Nitrogen  also  leaves  the  body  through  the  horn  formation.  The 
quantity  which  is  lost  in  this  manner  is,  though  it  cannot  be  ex- 
actly determined,  insignificant.  Man  loses  only  about  0.03  grm. 
nitrogen  daily  by  means  of  the  hair  and  nails  (Moleschott*)  and 
about  0.3-0.5  grm.  by  the  scaling  off  of  the  skin.  The  quantity  of 
nitrogen  which  leaves  the  body  under  ordinary  circumstances  by 
the  perspiration  must  be  so  small  that,  like  the  loss  by  the  horny 
structure,  it  need  not  be  considered  in  experiments  on  the  exchange 
of  material.  The  elimination  of  nitrogen  by  the  perspiration  need 
only  be  considered  in  cases  of  profuse  sweating. 

The  view  was  formerly  held  tliat  in  man  and  carnivora  an  elim- 
ination of  gaseous  nitrogen  took  place  through  the  skin  and  lungs, 
and  because  of  this,  on  comparing  the  nitrogen  of  the  food  with 
that  of  the  urine  and  fa3ces,  a  tiitrogeji  deficit  occurred  in  the  vis- 
ible elimination. 

This  question  has  been  the  subject  of  much  discussion  and  of 
numerous  investigations.  The  conclusion  has  been  drawn  from 
the  respiration  researches  of  Regnault  and  Reiset  ^  that  also  an 
exhalation  of  nitrogen  takes  place.  Seegen"  and  Nowak  '  especially 
have  recently  endeavored  to  prove  the  correctness  of  this  con- 
clusion.    Such  an  experiment  is,  however,  accompanied  with  so 

»  Zeitscbr.  f.  Biologie,  Bd.  20. 

*  Ihid.,  Bd.  15. 

3  Berl.  klin.  Woclienscbr.,  1887. 

*  Untersucb.  ziir  Naturlebie,  Bd.  12. 

'  Aunal.   d.  CLiin.  et  Pbys.  (3),   Tome  27,  and  Annal.  d.  Chem.  a.  Pbarm., 
Bd.  73. 

*  Wien.  Sitzungsber. ,  Bd.  71,  and  Pflilger's  Arcb.,  Bd.  25. 


612  METABOLISM. 

many  difBculties,  and  there  are  so  many  sources  of  error,  that  it 
can  scarcely  be  considered  as  conclusive.  In  fact,  Pette]S"KOFEK. 
and  YoiT '  have  demonstrated  the  existence  of  errors  in  the  experi- 
ments of  Seegei^  and  Nowak.  On  the  other  hand,  Pfluger  and 
Leo  °  have  found  no  appreciable  exhalation  of  nitrogen  in  rabbits." 
Also  many  investigators,  especially  Pettenkofer  and  VoiT,*  have 
shown  by  experiments  on  man  and  animals  that  with  the  proper 
quantity  and  qualit)^  of  food  we  can  bring  the  body  into  nitroge- 
nous eqiiilihrium,  in  which  the  quantity  of  nitrogen  voided  witli 
the  urine  and  feeces  is  equal  or  nearly  equal  to  the  quantity  con- 
tained in  the  food. 

The  experiments  made  by  Gruber  in  Voit's  institute  seem  ta 
be  especially  conclusive  on  this  jDoint.  Gruber  ""  fed  a  dog  seven- 
teen days  on  meat  which  in  all  contained  368.53  grms.  nitrogen,^, 
and  he  found  in  the  same  time  368.28  grms.  nitrogen  in  the  urine 
and  fseces.  In  later  experiments "  he  found  a  difference  varying 
only  between  —  0.21^  and  +  1^.  From  this  and  other  experiments 
we  may  conclude  with  Voit  that  a  deficit  of  nitrogen  does  not 
exist:  or  it  is  so  insignificant  that  in  experiments  upon  metabolism  it 
need  not  be  considered.  In  investigations  on  the  metabolism  of 
proteids  in  the  body,  ordinarily,  it  is  only  necessary  to  consider  the 
nitrogen  of  the  urine  and  feeces,  but  it  must  be  remarked  that  thfr 
nitrogen  of  the  urine  is  a  measure  of  the  extent  of  the  metabolism, 
of  the  proteids  in  the  body,  while  the  nitrogen  of  the  faeces  (after 
deducting  somewhat  less  than  1  grm.  on  mixed  diet)  is  a  measure 
of  the  non-absorbed  part  of  the  nitrogen  of  the  food. 

In  the  oxidation  of  the  proteids  in  the  organism  their  sulphur 
is  oxidized  into  sulphuric  acid,  and  on  this  depends  the  fact  that 
the  elimination  of  sulphuric  acid  by  the  urine,  which  in  man  is. 
only  to  a  small  extent  derived  from  the  sulphates  of  the  food,  makes 
nearly  equal  variations  as  the  elimination  of  nitrogen  by  the  urine. 
If  we  consider  the  amount  of  nitrogen  and  sulphur  in  the  proteids 
as  16^  and  Ifo  respectively,  then  the  proportion  between  the  nitrogen 
of  the  proteids  and  the  sulphuric  acid,  H^SO^,  produced  by  their 

'  Zeitschr.  f.  Biologie,  Bd.  16. 

2  Pfliiger's  Arch. ,  Bd.  36. 

8  Zuntz  and  Tacke,  Maly's  Jahresber.,  Bd.  16,  S.  361. 

*  See  Voit  in  Hermann's  Handbuch,  Bd.  6,  Th.  1. 

*  Zeitscbr.  f.  Biologie,  Bd.  16. 
« Ibid  ,  Bd.  19. 


CALCULATING    THE  EXTENT  OF  METABOLISM.         613 

"burning  is  in  the  ratio  5.2  : 1,  or  about  tlie  same  as  in  the  urine 
(see  page  515).  The  determination  of  the  quantity  of  sulphuric 
acid  eliminated  with  the  urine  gives  us  an  important  means  of  con- 
trolling the  extent  of  the  transformation  of  proteids,  and  such  a 
control  is  especially  important  in  cases  in  which  we  wish  to  study 
the  action  of  certain  nitrogenous  non-albuminous  bodies  on  the 
metabolism  of  proteids,  A  determination  of  the  nitrogen  alone  is 
not  sufficient  in  such  cases. 

If  it  is  found,  on  comparing  the  nitrogen  of  the  food  with  that 
■of  the  urine  and  f^ces,  that  there  is  an  excess  of  the  first,  this  means 
that  the  body  has  increased  its  stock  of  nitrogenous  substances — 
proteids.  If,  on  the  contrary,  the  urine  and  faeces  contain  more 
nitrogen  than  the  food  taken  at  the  same  time,  this  denotes  that 
the  body  is  giving  up  part  of  its  nitrogen — that  is,  a  part  of  its 
own  proteids  has  been  decomposed.  We  can,  from  the  quantity  of  ni- 
trogen, as  above  stated,  calculate  the  corresponding  quantity  of  pro- 
teids by  mutiplying  by  6.25.  Usually,  according  to  Voit's  propo- 
sition, the  nitrogen  of  the  urine  is  not  calculated  as  decomposed 
proteids,  but  as  decomposed  muscle-substance  or  flesh.  Lean  meat 
contains  on  an  average  about  3.4^  nitrogen;  hence  each  gramme  of 
nitrogen  of  the  urine  corresponds  in  round  numbers  to  about  80 
grms.  flesh.  The  assumption  that  lean  meat  contains  3.4,^  nitrogen 
is  arbitrary,  as  specially  shown  by  Pfluger,'  and  the  relationship 
of  N  :  C  in  the  proteids  of  dried  meat,  which  is  of  great  importance 
in  certain  experiments  on  metabolism,  is  given  different  by  various 
experimenters,  namely,  1  :  3.22  —  1  :  3.68.  Argutinsky  "  found  in 
ox-flesh,  after  complete  removal  of  fat  and  subtraction  of  glycogen, 
that  the  relationship  was  1  :  3.24. 

A  disproportionally  large  part  of  the  carbon  leaves  the  body  as 
carbon  dioxide,  which  escapes  chiefly  through  the  lungs  and  skin. 
The  remainder  of  the  carbon  is  eliminated  in  the  form  of  organic 
combinations  by  the  urine  and  faeces,  in  which  the  quantity  of  car- 
bon can  be  determined  by  elementary  analysis.  The  quantity  of 
gaseous  carbon  dioxide  eliminated  may  be  determined  by  means  of 
PettenKOFEr's  respiration  apparatus,  or  by  other  methods  as  de- 
scribed in  the  preceding  chapter.  By  multiplying  the  quantity  of 
carbon  dioxide  found  by  0.273  we  obtain  the  quantity  of  carbon 
eliminated  as  CO,.     If  we  compare  the  total  quantity  of  carbon 

'  Pflilger's  Arch.,  Bd.  51,  S.  2'29. 
«  Ibid. ,  Bd.  55. 


614  METABOLISM. 

eliminated  in  various  ways  with  the  carbon  contained  in  the  food  we 
obtain  some  idea  as  to  the  transformation  of  the  carbon  compounds. 
If  the  quantity  of  carbon  in  the  food  is  greater  than  in  the  excreta^ 
then  the  excess  is  deposited;  while  if  the  reverse  be  the  case  it 
shows  a  corresponding  loss  of  bodily  substance. 

The  nature  of  the  substances  here  deposited  or  lost,  whether  they 
consist  of  proteids,  fats,  or  carbohydrates,  is  learned  from  the  total 
quantity  of  nitrogen  of  the  excretions.  The  corresponding  quan- 
tity of  proteids  may  be  calculated  from  the  quantity  of  nitrogen, 
and,  as  the  average  quantity  of  carbon  in  the  proteids  is  known,  the 
quantity  of  carbon  which  corresponds  to  the  decomposed  proteids 
may  be  easily  ascertained.  If  the  quantity  of  carbon  thus  found  is 
smaller  than  the  quantity  of  the  total  carbon  in  the  excreta  it  is 
then  obvious  that  some  other  nitrogen-free  substance  has  been  con- 
sumed besides  the  proteids.  If  tlie  quantity  of  carbon  in  the  pro- 
teids is  considered  in  round  numbers  as  53^,'  then  the  relation 
between  carbon  (53)  and  nitrogen  (16)  is  as  3.3  :  1.  If  we  multi- 
ply the  total  quantity  of  nitrogen  eliminated  by  3.3  the  excess  of 
carbon  in  the  eliminations  over  the  product  found  represents  the 
carbon  of  the  decomposed  non-nitrogenous  compounds.  For  in- 
stance, in  tlie  case  of  a  person  experimented  upon,  10  grms.  nitro- 
gen and  200  grms.  carbon  were  eliminated  in  the  course  of  24  hours; 
then  these  62.5  grms.  proteid  correspond  to  33  grms.  carbon,  and 
the  difference,  200  —  (3.3  X  10)  —  167,  reprcocnts  the  quantity 
of  carbon  in  the  decomposed  non-nitrogenous  compounds.  If  we 
start  from  the  simplest  case,  starvation,  where  the  boly  lives  at  the 
expense  of  its  own  substance,  then,  since  the  quantity  of  carbohy- 
drates as  compared  to  the  fats  of  the  body  is  ext::emely  small,  in 
such  cases  in  order  to  avoid  mistakes  the  assumption  must  be  made 
that  the  person  experimented  upon  has  only  used  fat  and  proteids. 
As  animal  fat  contains  on  an  average  76.5^  carbon,  the  quantity  of 
transformed  fat  may  be  calculated  by  multiplying  the  carbon  by 

— —  =  1.3.  In  the  case  of  the  above  example  the  person  experi- 
mented upon  would  have  used  62,5  grms.  proteids  and  167  X  1.3 
=  217  grms.  fat  of  his  own  body  in  the  course  of  the  24  hours. 

Starting  from  the  nitrogen  balance,  we  can  calculate  in  the  same 
way  whether  an  excess  of  carbon  in  the  food  as  compared  with  the 
quantity  of  carbon  in  the  excreta  is  retained  by  the  body  as  pro- 

'  This  figure  is  perhaps  a  little  too  high. 


RESPTRATOUT   QUOTIENT.  615 

teids  or  fat  or  as  both.  On  the  other  hand,  with  an  excess  of 
carbon  in  the  excreta  we  can  calculate  how  much  of  the  loss  of  the 
substance  of  tlie  body  is  due  to  a  consumption  of  the  proteids  or  of 
fat  or  of  both. 

The  quantity  of  water  and  mineral  bodies  voided  with  the  urine 
and  faeces  can  easily  be  determined.  The  quantity  of  water  elimi- 
nated by  the  skin  and  lungs  may  be  directly  determined  by  means 
of  Pettenkofer's  apparatus.  The  quantity  of  oxygen  taken  up  is 
calculated  as  the  dilference  between  the  weight  of  the  individual 
before  the  experiment  plus  all  the  directly  determined  substances 
taken  in,  and  the  final  weight  of  the  individual  plus  all  his  excreta. 

The  oxygen  may,  according  to  the  methods  given  in  the  pre- 
ceding chapter,  be  directly  determined,  and  such  a  determination 
with  the  simultaneous  estimation  of  the  carbon  dioxide  eliminated  is 
of  great  importance  in  the  study  of  metabolism. 

On  comparing  the  inspired  and  the  expired  air  we  learn,  on  meas- 
uring them  when  dry  and  at  the  same  temperature  and  pressure, 
that  the  volume  of  the  expired  air  is  less  than  that  of  the  inspired  air. 
This  depends  upon  the  fact  that  not  all  of  the  oxygen  appears  again 
in  the  expired  air  as  carbon  dioxide,  because  it  is  not  only  used  in  the 
oxidation  of  carbon,  but  also  in  part  in  the  formation  of  water,  sul- 
phuric acid,  and  other  bodies.  The  volume  of  expired  carbon  dioxide 
is  regularly  less  than  the  volume  of  the  inspired  oxygen,  and  the 

CO^ 
relation  -r^-?  which  is  called  the  respiratory  quotient,  is  generally 

less  than  1. 

The  magnitude  of  the  respiratory  quotient  is  dependent  upon  the 
kind  of  substances  destroyed  in  the  body.  In  the  combustion  of  pure 
carbon  one  volume  of  oxygen  yields  one  volume  of  carbon  dioxide, 
and  the  quotient  is  therefore  equal  to  1.  The  same  is  true  in  the 
burning  of  carbohydrates,  and  in  the  exclusive  decomposition  of 
carbohydrates  in  the  animal  body  the  respiratory  quotient  must  be 
approximately  1.  In  exclusive  metabolism  of  proteids  it  is  0.73, 
and  with  the  decomposition  of  fat  it  is  0.7.  In  starvation,  as  the 
animal  draws  on  its  own  flesh  and  fat,  the  respiratory  quotient  must 
be  a  close  aj^proach  to  the  latter  figure.  The  respiratory  quotient 
therefore  gives  important  explanations  on  the  quality  of  the  material 
decomposed  in  the  body,  naturally  with  the  supposition  that  the- 
elimination  of  carbon  dioxide,  independent  of  the  formation  of 
carbon  dioxide,  is  not  influenced  by  special  conditions,  such  as 
alternation  of  the  respiratory  mechanism. 


(i  1 6  METABOLISM. 

It  is  also  ]30ssible  in  systematized  experimentation  so  to  carry  on 
the  metabolism  experiments  that  the  decomposition  material  of  the 
body — as  shown  by  the  respiratory  quotient — remains  qualitatively 
the  same,  at  least  for  a  short  time.  In  such  experiments  it  has  been 
shown,  especially  by  Zuntz  '  and  his  pupils,  that  the  extent  of 
oxygen  consumption  may  be  taken  as  a  measure  for  the  action  of 
different  influences  on  the  extent  of  metabolism.  This  possibility 
is  based  on  the  fact  proven  by  Pfluger  ^  and  his  pupils,  and  by 
VoiT,'  that  the  consumption  of  oxygen  within  wide  limits  is  inde- 
pendent of  the  supply  of  oxygen,  and  is  exclusively  dependent  upon 
the  oxygen  demand  of  the  tissues.  For  certain  reasons  ^  the  con- 
sumption of  oxygen  gives  indeed  a  better  conclusion  than  the 
elimination  of  carbon  dioxide  as  to  the  extent  of  exchange  of  material 
and  energy  ;  but  as  the  same  quantity  of  oxygen  (100  grms.)  con- 
sumes different  quantities  of  fat,  carbohydrates,  and  proteids  in  the 
body — namely,  35,  84.4,  and  74.4  grms.  respectively — the  respira- 
tory quotient  must  also  be  determined,  in  order  to  ascertain  the 
nature  of  the  substance  burnt  in  the  body,  by  the  simultaneous 
determination  of  the  elimination  of  carbon  dioxide. 

I.  Potential  Energy  and  the  Relative   Nutritive 
Value  of  Various  Organic  Foods. 

With  the  organic  foods  the  organism  receives  a  supply  of  poten- 
tial energy  which  is  converted  into  living  force  in  the  body.  This 
potential  energy  of  the  various  foods  may  be  represented  by  the 
amount  of  heat  which  is  set  free  in  their  combustion.  This  quan- 
tity of  heat  is  expressed  as  calories,  and  a  small  calorie  is  the  quan- 
tity of  heat  necessary  to  warm  1  grm.  water  from  0°  to  1°  0.  A 
large  calorie  is  the  quantity  of  heat  necessary  to  warm  1  kilo  water 
1°  C.  Here  and  in  the  following  pages  large  calories  are  to  be  under- 
stood. We  have  numerous  investigations  by  different  experimenters, 
such  as  FRANKLA.ND,  Danilewski,  Rubner,*  Berthelot,'  Stoh- 

1  See  Chapter  XVII,  foot-note  4,  p.  604. 

2  Pfluger's  Arch.,  Bdd.  6,  10  u.  14  ;  Finkler,  ihid.,  Bd.  10  ;  Finkler  and 
Oertmann,  ibid.,  Bd.  14. 

"  Zeitsclir.  f.  Biologie,  Bdd.  11  u.  14. 

*  See  Ad.  Magnus-Levy,  Pfluger's  Arch.,  Bd.  55,  S.  7. 

*  Zeit^chr.  f.  Biologie,  Bd.  31,  where  the  works  of  Frankland  and 
Danilewski  are  cited. 

«  Compt.  reud..  Tomes  103,  104,  110. 


CALORIFIC   VALUE  OF  FOODS.  (U7 

MANN,'  and  others,  on  the  calorific  value  of  different  foods.  The 
following  results,  which  represent  the  calorific  value  of  a  few  nutri- 
tive bodies  on  complete  combustion  outside  of  the  body  to  the 
highest  oxidation  products,  are  taken  from  Stohmann's''  latest 
work. 

Calories. 

Casein 5.86 

Ovalbumin 5.74 

Congl  utin 5  48 

Pioteid  (average) 5.71 

Animal  tissue-fat 9.50 

Butter-fat 9.33 

Cane-sugar 3. 96 

Lactose 3.95 

Dextrose 3.74 

Siaich 4.19 

Fat  and  carbohydrates  are  completely  burnt  in  the  body,  and 
we  can  therefore  consider  their  combustion  equivalent  as  a  measure 
of  the  living  force  developed  by  them  within  the  organism.  We 
generally  designate  9.3  and  4.1  calories  for  each  grm.  of  sub- 
stance as  the  average  for  the  physiological  calorific  value  of  fats 
and  carbohydrates  respectively. 

The  proteids  act  differently  from  the  fats  and  carbohydrates. 
They  are  only  incompletely  burnt,  and  they  yield  certain  decom- 
position products,  which,  leaving  the  body  with  the  excreta,  still 
represent  a  certain  quantity  of  potential  energy  which  is  lost  for  the 
body.  The  heat  of  combustion  of  the  proteids  is  smaller  within 
the  organism  than  outside  of  it,  and  they  must  therefore  be  specially 
determined.  For  this  purj)0se  Rubner  '  fed  a  dog  on  washed  meat, 
and  he  subtracted  from  the  heat  of  combustion  of  the  food  the  heat 
of  combustion  of  the  urine  and  fasces,  which  corresponded  to  the 
food  taken  plus  the  quantity  of  heat  necessary  for  the  swelling  up 
of  the  proteids  and  the  solution  of  the  urea.  Eubner  has  also  tried 
to  determine  the  heat  of  combustion  of  the  proteids  (muscle-pro- 
teids)  decomposed  in  the  body  of  rabbits  in  starvation.  According 
to  these  investigations,  the  physiological  heat  of  combustion  in  cal- 
ories for  each  gramme  of  substance  is  as  follows: 

1  grm.  of  the  Diy  Substance.  Calories. 

Proteids  from  meat 4.4 

Muscle 4.0 

Proteids  in  starvation 3.8 

Fat  (average  for  various  fats) 9.3 

Carboliydrates  (calculated  average) 4. 1 

>  Zeitschr.  f.  Biologie,  Bd.  31. 

•  L.  c. 

»  Zeitschr.  f.  Biologie,  Bd.  21. 


618  METABOLISM. 

The  physiological  combustion  value  of  the  various  foods  belong- 
ing to  the  same  grou|)  is  not  quite  the  same.  It  is,  for  instance, 
3.97  calories  for  a  vegetable  proteid,  conglutin,  and  4.42  calories 
for  an  animal  proteid  body,  syntonin.  According  to  Eubneb 
we  may  consider  the  normal  heat  value  per  1  grm.  of  animal 
proteid  as  4.23  calories,  and  of  vegetable  proteid  as  3.96  cal- 
ories. When  a  person  on  a  mixed  diet  takes  about  60^  of  the 
proteids  from  animal  foods  and  about  40^  from  vegetable  foods, 
we  may  consider  the  value  of  1  grm.  of  the  proteid  of  the  food 
as  about  4.1  calories.  The  physiological  value  of  each  of  the 
three  chief  groups  of  organic  foods,  by  their  decomposition  in  the 
body,  is  in  round  numbers  as  follows : 

Calories. 

1  grm.  proteid 4.1 

1     "     fat 9.3 

1     "      carbohydrate 4.1 

As  will  be  shown,  the  fats  and  carbohydrates  may  decrease  the 
metabolism  of  proteids  in  the  body,  while,  on  the  other  hand,  the 
quantity  of  proteids  in  the  body  or  in  the  food  acts  on  the  meta- 
bolism of  fat  in  the  body.  In  physiological  combustion  the  various 
foods  may  replace  one  another  to  a  certain  extent,  and  it  is  there- 
fore important  to  know  in  what  proportion  they  can  replace  one 
another.  The  investigations  made  by  Rubner  have  taught  that 
this,  if  it  relates  to  the  force  and  heat  production  in  the  animal 
body,  is  in  proportions  that  correspond  with  the  figures  of  the  heat 
value  of  the  same.  This  is  apparent  from  the  following  table.  In 
this  we  find  the  weight  of  the  various  foods  equal  to  100  grms.  fat, 
a  part  determined  from  experiments  on  animals  and  a  part  calcu- 
lated from  figures  of  the  heat  values. 

Table    1. 

100  grms.  fat  are  equal  to  or  isodynamic  with: 

From  Experiments         From  the  Difference, 

on  Animals.  Heat  Value.  percent. 

Syntonin 225  213  +5.6 

Muscle-tiesh  (dried) 243  235  +4.3 

Starch 332  239  +1.3 

Cane-sugar 234  335  -  0 

Grape-sugar 356  253  -0 

From  the  given  isodynamic  value  of  the  various  foods  it  follows 
that  these  substances  replace  one  another  in  the  body  almost  in 
exact  ratio  to  the  potential  energy  contained  in  them.  Thus  in 
round  numbers  227  grms.  proteid  and  carbohydrate  are  equal  to  or 


METABOLISM  IN  STARVATION.  619 

isodynamic  with  100  grms.  fat  in  regard  to  source  of  energy,  because 
each  yields  930  calories  on  combustion  in  the  body. 

By  means  of  recent  very  important  calorimetric  investigations 
RuBNER '  has  shown  that  the  heat  produced  in  an  animal  in  several 
series  of  experiments  extending  over  45  days  corresponded  to 
within  0.47^  with  the  physiological  heat  of  combustion  calculated 
from  the  decomposed  body  and  foods. 

This  isodynamic  law  is  of  fundamental  value  in  the  study  of  meta- 
bolism and  nutrition.  By  this  law  it  is  possible  to  consider  the 
processes  of  metabolism  as  more  uniform.  The  quantity  of  energy 
in  the  foods  may  be  used  as  a  measure  for  the  total  consumption  of 
energy,  and  the  knowledge  of  the  quantity  of  energy  in  the  foods 
must  also  be  the  basis  for  the  calculation  of  dietaries  for  human 
beings  under  various  conditions. 

II.  Metabolism  in  Starvation. 

In  starvation  the  decomposition  in  the  body  continues  uninter- 
ruptedly, though  with  decreased  intensity  ;  but,  as  it  takes  place  at 
the  expense  of  the  substance  of  the  body,  it  can  only  continue  for 
a  limited  time.  When  an  animal  has  lost  a  certain  fraction  of  the 
mass  of  the  body  death  is  the  result.  This  fraction  varies  with  the 
condition  of  the  body  at  the  beginning  of  the  starvation  period. 
Fat  animals  succumb  when  the  weight  of  the  body  has  sunk  to  4  of 
the  original  weiglit.  Otherwise,  according  to  Chossat,'  animals 
die  as  a  rule  when  the  weight  of  the  body  has  sunk  to  f  of  the  orig- 
inal weight.  The  period  when  death  occurs  from  starvation  not 
only  varies  with  the  varied  nutritive  condition  at  the  beginning 
of  starvation,  but  also  with  the  more  or  less  active  exchange  of 
material.  Tliis  is  more  active  in  small  and  young  animals  than  in 
large  and  older  ones,  but  different  classes  of  animals  show  an  un- 
equal activity.  Children  succumb  in  starvation  in  3-5  days  after 
having  lost  \  of  their  bodily  mass.  Grown  persons,  as  observed 
on  Succi,'  may  starve  for  20  days  without  lasting  injury  ;  and  we 
have  statements  of  even  over  40-50  days'  starvation.  Dogs  can 
live  without  food  from  4-8  weeks,  birds  5-20  days,  snakes  more 
than  half  a  year,  and  frogs  more  than  a  year. 

>  Zeitschr.  f.  Biologie,  Bd.  30. 

»  Cited  from  Voit  in  Hermann's  Handbuch,  Bd.  6,  Thl.  1,  S.  100. 

•  See  Luciani,  Das  Hungern.     Hamburg  u.  Leipzig,  1890. 


620  METABOLISM. 

In  starvation  the  weight  of  the  tody  decreases.  The  loss  of 
weight  is  greatest  in  the  first  few  days,  and  then  decreases  rather 
uniformly.  In  small  animals  the  absolute  loss  of  weight  per  day  is 
naturally  smaller  than  in  larger  animals.  The  relative  loss  of 
weight — that  is,  the  loss  of  weight  of  the  unit  of  the  weight  of  the 
body,  namely,  1  kilo — is,  on  the  contrary,  greater  in  small  animals 
than  in  larger  ones.  The  reason  for  this  is  that  the  smaller  animals 
have  a  greater  surface  of  body  in  proportion  to  their  mass  than  larger 
animals,  and  the  greater  loss  of  heat  caused  thereby  must  be  replaced 
by  a  more  active  consumption  of  material. 

It  follows  from  the  decrease  in  the  weight  of  the  body  that  the 
absolute  extent  of  metabolism  must  diminish  in  starvation.  If,  on 
the  contrary,  we  refer  the  extent  of  the  metabolism  to  the  unit  of  the 
weight  of  the  body,  namely,  1  kilo,  we  find  that  this  quantity  re- 
mains nearly  unchanged  during  starvation.  The  investigations  of 
ZuNTZ,  Lehmann,  and  others '  on  Cetti  showed  on  the  3d  to  6th 
day  of  starvation  an  average  consumption  4.65  c.  c.  oxygen  per  kilo 
in  one  minute  and  on  the  9th  to  11th  day  an  average  of  4.73  c.  c. 
The  calories,  as  a  measure  of  the  metabolism,  fell  on  the  1st  to  5th 
day  of  starvation  from  1850  to  1600  calories,  or  from  32.4  to  30 
per  kilo,  and  he  remained  nearly  unchanged,  if  we  refer  to  the  unit 
of  bodily  weight. 

As  the  metabolism  in  starvation  takes  place  at  the  expense  of 
the  constituents  of  the  body,  it  must  take  place  in  essentially  the 
same  way  in  both  carnivora  and  herbivora.  As  the  food  of  the 
herbivora  is  ordinarily  richer  in  carbohydrates  and  non-nitrogenous 
nutritive  bodies  than  that  of  the  carnivora,  so  in  starvation  the 
body  of  the  herbivora  becomes  relatively  richer  in  proteids.  On  thjs 
account  the  elimination  of  nitrogen  is  increased  in  herbivora  in  the 
first  part  of  the  period  of  starvation.  In  carnivora  the  elimination 
of  nitrogen  decreases,  as  a  rule,  immediately  at  the  beginning  of  the 
starvation,  and  in  the  later  periods  only  small  quantities  of  nitrogen 
are  voided  by  herbivora  as  well  as  by  carnivora. 

The  extent  of  the  metabolism  of  proteids,  or  the  elimination  of 
nitrogen  by  the  urine,  which  is  a  measure  for  the  same,  does  not 
show  in  carnivora  any  uniform  decrease  during  the  entire  period  of 
starvation.  During  the  first  few  days  the  elimination  of  nitrogen 
is  greatest,  and  the  quantity  of  the  same  depends  essentially  upon 
the  amount  of  proteids  in  the  organism  and  the  nature  of  the  food 

'  Berlin.  Idin.  Wocbensclir.,  1887. 


METABOLISM  IX  STARVATION.  P,21 

previously  taken.  The  richer  the  body  is  in  proteids  from  the  food 
previously  taken  the  greater  is  the  metabolism  of  joroteids,  or,  in 
other  words,  the  elimination  of  nitrogen  during  the  first  days  of 
starvation  is  greater.  The  rapidity  with  which  the  elimination  of 
nitrogen  decreases  in  the  first  days  depends  also,  according  to  Yoit, 
upon  the  proteid  condition  of  the  body.  It  decreases  more  quickly — 
that  is,  the  curve  of  the  decrease  is  more  sudden — the  first  days  of 
starvation,  as  a  rule,  the  richer  the  food  was  in  proteids  which  was 
taken  before  starvation.  This  condition  is  apparent  from  the  fol- 
lowing table.  This  table  contains  three  different  starvation  experi- 
ments made  by  Voit  '  on  the  same  dog.  This  dog  received  2500 
grms.  flesh  daily  before  the  first  series  of  experiments,  1500  grms. 
flesh  daily  before  the  second  series,  and  a  mixed  food  relatively 
poor  in  nitrogen  before  the  third  series. 

Table  II. 

Dav  nf  qtarvfttimi  Grammes  of  Urea  Eliminated  in  the  Twenty-four  Hours. 

1 60.1  26.5  138 

2 24.9  18.6  .      11.5 

3 191  15.7  10.2 

4 17.3  14.9  12.2 

5  12.3  14.8  12.1 

6 13.3  12.8  12.6 

7 12.5  12.9  11.3 

8 10.1  12.1  10.7 

Other  conditions,  such  as  varying  quantities  of  fat  in  the  body, 
have  an  influence  on  the  rapidity  with  which  the  nitrogen  is 
eliminated  during  the  first  days  of  starvation.  After  the  first  few 
days  the  elimination  of  nitrogen,  as  is  seen  in  the  above  table,  is 
more  uniform,  and  as  the  starvation  proceeds  it  decreases  as  a  rule 
very  slowly  and  uniformly.  Cases  also  occur  in  which  the  elimina- 
tion of  nitrogen  becomes  constant  in  these  stages,  and  towards  the 
end,  indeed,  the  elimination  of  nitrogen  increases.  This  so-called 
premortal  increase  always  occurs  as  soon  as  the  adipose  tissue  in 
the  body  has  sunk  to  a  certain  point,  and  it  also  depends  on  the 
fact  that  as  soon  as  the  fat  is  consumed  a  corresponding  increase 
in  the  decomposition  of  proteids  is  necessary  for  the  generation  of 
heat  as  well  as  of  other  forms  of  living  force. 

Besides  the  proteids  the  fat  occurring  in  the  body  is  also  decon;- 
posed  in  starvation.  Since  fat  has  a  diminishing  influence  on  the 
destruction  of  proteids  (see  further  on),  the  elimination  of  nitrogen 

'  Physiol,  des  StofEwechsels,  etc.,  in   Hermann's  Handbuch,  Bd.  6,  Thl.   1, 
S.  89. 


622  METABOLISM. 

in  starvation  is  less  in  fat  than  in  lean  individuals.  For  instance, 
only  9  grms.  of  urea  were  voided  in  twenty-four  hours  during  the 
later  stages  of  starvation  by  a  well-nourished  and  fat  person  suffer- 
ing from  disease  of  the  brain,  while  I.  Mtjjstk  found  that  20-29 
grms.  urea  were  voided  daily  by  Cetti,'  who  had  been  poorly  fed. 
Like  the  destruction  of  proteids  during  starvation,  the  decom- 
position of  fat  proceeds  uninterruptedly.  The  decomposition  of 
fat  does  not  show*  so  great  and  rapid  a  decrease  in  the  first  days  of 
starvation  as  the  destruction  of  proteids.  PETTEiq"KOFER  and  YoiT 
found,  for  instance,  in  a  starving  dog  the  following  losses  of  pro- 
teids and  fat  from  the  body  on  different  days  of  starvation: 

Table  III. 

Pi„„  Loss  of  Loss  of 

■"^y*  Flesh.  Calories.2  Fat.  Calories. 

2 , 341  29";. 3  86  799  8 

5  167     145.6  103     957.9 

8 ..138     120.1  99     920.7 

The  consumption  of  fat  on  the  second  day,  when  the  decom- 
position of  proteids  was  considerable,  was  indeed  less  than  in  the 
following  days.  The  reason  for  this  was  that  the  animal  had  pre- 
viously been  fed  with  abundant  quantities  of  meat  (2500  grms.).  If 
the  exchange  is  expressed  as  calories  we  find  for  the  fifth  and  eighth 
days  of  starvation  that  13.2^  and  11.5^  respectively  of  the  total  cal- 
ories was  covered  by  the  decomposition  of  proteids  and  86.8^  and 
85.5^  by  tbe  decomposition  of  fat.  Other  observations  on  animals 
as  well  as  man  have  led  to  a  similar  result,  and  we  can  assume  that 
in  starvation  ordmarily  the  greatest  part  of  the  expenditure  is 
replaced  by  the  decomposition  of  fat  and  only  a  small  part  by  the 
decomposition  of  proteids. 

The  investigations  on  the  exchange  of  gas  in  starvation  have 
shown,  as  previously  mentioned,  that  the  absolute  extent  of  the 
same  is  diminished,  but  that,  when  the  cousumption  of  oxygen  and 
elimination  of  carbon  dioxide  is  calculated  on  the  unit  of  weight  of 
the  body,  1  kilo,  this  quantity  quickly  sinks  to  a  minimum  and 
then  remains  unchanged,  or  on  the  continuation  of  the  starvation 
may  indeed  rise.  It  is  a  generally  known  fact  that  the  body  tem- 
perature of  starving  animals  remains  rather  constant  without  show- 
ing any  appreciable  decrease  during  the  greater  part  of  tlie  star- 

1  L.  c. 

^  The  calories  of  tlie   decomposed    proteids  were  calculated  by  the  author, 
assuming  that  the  flesh  contains  3.4%  nitrogen  as  proteids. 


METABOLISM  IN  STARVATIOX. 


623 


vation  period.     The  temperature  of  the  animal  first  sinks  a  few 
days  before  death  and  starvation  death  occurs  at  about  33-30°  C. 

From  wliat  has  been  said  on  the  respiratory  quotient  it  follows 
that  in  starvation  it  is  about  the  same  as  with  exclusive  fat  and 
meat  as  food,  namely,  about  0.7.  This  is  often  the  case,  but  it  may 
also  be  indeed  lower,  0.65 — 0.50,  as  observed  in  the  cases  of  Cetti 
and  Succi.  As  explanation  for  this  unexpected  behavior  we  admit 
of  a  storage  of  incompletely  oxidized  substances  in  the  body  during 
starvation. 

Water  passes  uninterruptedly  from  the  body  in  starvation  even 
when  none  is  given.  If  the  quantity  of  water  in  the  tissues  rich  in 
proteids  is  considered  as  70-80^,  and  the  quantity  of  proteids  in 
the  same  20^,  then  for  each  gramme  of  destroyed  proteids  about 
4  grammes  of  water  are  set  free.  A  special  increase  in  the  demand 
for  water  does  not  seem  to  occur  in  starving  animals. 

The  mineral  svbstances  leave  the  body  uninterruptedly  in  star- 
vation until  death,  and  the  influence  of  the  destruction  of  tissues  is 
plainly  perceptible  by  their  elimination.  Because  of  the  destruction 
of  tissues  rich  in  potassium  the  proportion  between  potassium  and 
sodium  in  the  urine  changes  in  starvation,  so  that,  contrary  to  the 
normal  conditions,  the  potassium  is  eliminated  in  proi^ortionally 
greater  quantities.  MuifK  also  observed  in  Cetti's*  case  a  relative 
increase  in  the  phosphoric  acid  and  calcium  in  the  urine  during 
starvation,  which  was  due  to  an  increased  exchange  of  bone-sub- 
stance. 

Table  IV. 


Pigeon  (Chossat). 


Adipose  tissue 93  per 

Spleea 71 

Pancreas 64 

Liver 52 

Heart 45 

Intestine 42 

Muscles 42 

Testicles 

Skin 33 

Kidneys 33 

Lungs 22 

Bones 17 

Nervous  system 2 


cent. 


Male  Cat  (Yoit). 
97  per  cent. 
67 
17 
54 
3 
18 
31 
40 
21 
26 
18 
14 


The  question  as  to  the  participation  of  the  different  organs  in 
the  loss  of  weight  of  the  body  during  starvation  is  of  special  interest. 
To  illustrate  this  question  we  have  given  above  the  results  of  Chos- 

>L.  c. 


624  METABOLISM. 

sat's  '  experiments  on  pigeons  and  those  of  Voit  on  a  male  cat. 
The  results  are  percentages  of  weight  lost  from  the  original  weight 
of  the  organ. 

The  total  quantity  of  blood,  as  well  as  the  quantity  of  solids  con- 
tained therein,  decreases,  as  Panum  °  has  shown,  in  the  same  pro- 
portion as  the  weight  of  the  body.  The  statements  in  regard  to 
the  loss  of  water  by  different  organs  are  somewhat  contradictory; 
according  to  Lukjanow,'  it  seems  that  the  various  organs  act 
somewhat  differently  in  this  respect. 

The  above- tabulated  results  cannot  serve  as  a  measure  of  the 
metabolism  in  the  various  organs  during  starvation.  For  instance, 
the  nervous  system  shows  only  a  small  loss  of  weight  as  compared 
with  bhe  other  organs,  but  from  this  it  must  not  be  concluded  that 
the  exchange  of  material  in  this  system  of  organs  is  least  active. 
The  condition  may  be  quite  different;  for  one  organ  may  derive  its 
nutriment  during  starvation  from  some  other  organ  and  exist  at  its 
expense.  A  positive  conclusion  cannot  be  drawn  in  regard  to  the 
activity  of  the  metabolism  in  an  organ  from  the  loss  of  weight  of 
that  organ  in  starvation. 

The  knowledge  of  metabolism  during  starvation  is  of  the  greatest 
importance  in  the  study  of  nutrition,  and  it  forms  to  a  certain 
extent  the  starting-point  for  the  study  of  metabolism  under  different 
physiological  and  pathological  conditions.  To  answer  the  question 
whether  the  metabolism  of  a  person  in  a  special  case  is  abnormally 
increased  or  diminished  it  is  naturally  very  important  to  know  the 
average  extent  of  metabolism  of  a  healthy  person  under  the  same 
circumstances  for  comparison.  This  quantity  can  be  called  the 
abstinent  value,  namely,  the  extent  of  metabolism  used  in  absolute 
bodily  rest  and  inactivity  of  the  intestinal  tract.  As  measure  of 
this  quantity  we  determine  according  to  Geppeet-Zuntz  the  extent 
of  gaseous  exchange,  and  especially  the  consumption  of  oxygen,  of  a 
person  lying  down,  best  sleeping,  in  the  early  morning  and  at  least. 
12  hours  after  a  light  meal  not  rich  in  carbohydrates.  The  gas 
volume  reduced  to  0°  C.  and  760  mm.  Hg  pressure  is  calculated  on 
1  kilo  of  body  weight  and  for  1  minute.  The  results  vary  between 
3  and  4.5  for  the  consumption  of  oxygen  and  between  2.5  and  3.5 

1  Cited  from  Voit  in  Hermann's  Handbuch,  Bd.  6,  Tbl.  1,  S.  96  u.  97.      . 
»  Virchow's  Arch.,  Bd.  29.  , 

»  Zeitsclir.  f.  pliysiol.  Cbem.,  Bd.  13. 


LACK  OF   WATER  AND  MINERAL  SUBSTANCES.         625 

c.  c.  for  the  carbou  dioxide.     As  average  we  can  accept  3.81  c.  c. 
oxygen  and  3.08  c.  c.  carbon  dioxide.' 

The  extent  of  proteid  destruction  cannot  be  determined  in 
transient  experiments,  and  for  these  reasons  only  the  values  found 
after  several  days  of  starvation  are  useful.  In  the  starvation  experi- 
ments on  Cetti  and  Succi  the  elimination  of  nitrogen  per  kilo  in 
the  fifth  to  the  tenth  starvation  day  was  0.150-0.202  grm.  N. 

III.  Metabolism  with  Inadequate  Nutrition. 

The  food  may  be  quantitatively  insufficient,  and  the  final  result 
is  absolute  inanition.  The  food  may  also  be  qualitatively  insuffi- 
cient or,  as  we  say,  inadequate.  This  occurs  when  any  of  the 
necessary  nutritive  bodies  are  absent  in  the  food,  while  the  others 
occur  in  sufficient  or  perhaps  indeed  in  excessive  amounts. 

Lack  of  Water  in  the  Food.  The  quantity  of  water  in  the 
organism  is  greatest  during  foetal  life,  and  then  decreases  with 
increasing  age.  Naturally,  the  quantity  differs  in  various  organs.. 
The  tissue  in  the  body  being  poorest  in  water  is  the  enamel,  which 
is  almost  free,  containing  only  2  p.  m.  water,  the  teeth  about  100 
p.  m.,  the  fatty  tissues  60-120  p.  m.  The  bones  with  140-440 
p.  m.  and  the  cartilage  with  540-740  p.  m,  are  somewhat  richer 
in  water,  while  the  muscles,  blood,  and  glands  with  750  to  more 
than  800  p.  m.  are  still  richer.  The  quantity  of  water  is  even 
greater  in  the  animal  fluids  (see  preceding  chapter),  and  the  adult 
body  coutains  in  all  about  630  p.  m.  water.^  If  we  bear  in  mind 
that  two  thirds  of  the  animal  organism  consists  of  water;  that  water 
is  of  the  very  greatest  importance  in  the  normal,  physical  composi- 
tion of  the  tissues;  moreover  that  all  flow  of  juices,  all  exchange  of 
substance,  all  supply  of  nutrition,  all  increase  or  destruction,  and 
all  discharge  of  the  products  of  destruction  are  dependent  upon  the 
presence  of  water;  besides  this,  that  by  its  evaporation  it  is  an  im- 
portant regulator  of  the  temperature  of  the  body, — we  perceive  that 
water  must  be  necessary  for  life.  If  the  loss  of  water  be  not 
replaced  by  fresh  supplies  sooner  or  later,  the  organism  succumbs. 

Lack  of  Mineral  Substatices  in  the  Food.  We  are  chiefly  indebted 
to  LiEBiG  for  showing  that  the  mineral  substances  are  just  as  neces- 

'  These  figures  are  taken  from  v.  Noorden's  Lehrbucb  der  Path,  des  Stoff- 
wechsels,  S.  94. 

'  See  Voit  in  Hermann's  Handbuch,    Bd.  6,  Thl.  1.  S.  345. 


626  METABOLISM. 

aary  for  the  normal  composition  of  the  tissues  and  organs,  and  for 
the  normal  course  of  the  processes  of  life,  as  the  organic  constituents 
of  the  body.  The  importance  of  the  mineral  constituents  is  evident 
from  the  fact  that  there  is  no  animal  tissue  or  animal  fluid  which 
does  not  contain  mineral  substance,  and  also  from  the  fact  that 
certain  tissues  or  elements  of  tissues  contain  regularly  certain  min- 
eral substances  and  not  others,  which  explains  the  unequal  division 
of  the  potassium  and  sodium  compounds  in  the  tissues  and  fluids. 
With  the  exception  of  the  skeleton,  which  contains  about  320  p.  m. 
mineral  bodies  (Volkmann  '),  the  animal  fluids  or  tissues  are  poor 
in  inorganic  constituents,  and  the  quantity  of  such  only  amounts, 
as  a  rule,  to  about  10  p.  m.  Of  the  total  quantity  of  mineral  sub- 
stances in  the  organism,  the  greatest  part  occurs  in  the  skeleton, 
830  p.  m.,  and  the  next  greatest  in  the  muscles,  about  100  p.  m. 
(Volkmann). 

The  mineral  bodies  seem  to  be  partly  dissolved  in  the  fluids  and 
partly  combined  with  organic  substances.  In  accordance  with  this 
the  organism  persistently  retains,  with  food  poor  in  salts,  a  part  of 
the  mineral  substances,  also  such  as  are  soluble,  as  the  chlorides. 
On  the  burning  of  the  organic  substances  the  mineral  bodies  com- 
bined therewith  are  set  free  and  may  be  eliminated.  It  is  also  ad- 
mitted that  they  in  part  combine  with  the  new  products  of  the 
burning,  and  also  that  they  in  part  are  attached  to  organic  nutritive 
bodies  poor  in  salts  or  nearly  salt-free,  which  are  absorbed  from  the 
intestinal  canal  and  are  thus  retained  (Voit,  Forster^). 

If  this  statement  be  correct,  it  is  possible  that  a  constant  supply 
of  mineral  substances  with  the  food  is  not  absolutely  necessary,  and 
that  the  amount  of  inorganic  bodies  which  must  be  administered  is 
insignificant.  The  question  whether  this  be  so  or  not  has  not, 
especially  in  man,  been  sufficiently  investigated;  but  generally  we 
consider  the  need  of  mineral  substances  by  man  as  very  small.  It 
may,  however,  be  assumed  that  man  usually  takes  with  his  food  a 
considerable  excess  of  mineral  substances. 

Investigations  on  animals  in  regard  to  the  action  of  an  insuffi- 
cient supply  of  mineral  substances  with  the  food  have  been  made  by 
several  investigators,  especially  Forster.  He  observed,  on  experi- 
menting on  dogs  and   pigeons  with  food  as  poor  as  possible  in 

'  See  Voit  in  Hermann's  Handbucb,  Bd.  6,  Tbl.  1,  S.  353. 
"^  Zeitscbr.  f.  Biologie,  Bd.  9.     See  also  Voit  in  Hermann's  Handbucli,  Bd. 
.6.  Tbl.  1,  S.  354. 


LACK  OF  MINERAL  SUBSTANCES.  627 

mineral  substances,  a  very  suggestive  disturbance  of  the  functions 
of  the  organs,  especially  the  muscles  and  the  nervous  system,  and 
death  resulted  after  a  time,  indeed  earlier  than  in  complete  starva- 
tion. In  opposition  to  these  observations  Bunge  '  has  suggested 
that  the  early  death  in  these  cases  was  not  caused  by  the  lack  of 
mineral  salts,  but  more  likely  by  the  lack  of  bases  necessary  to 
neutralize  the  sulphuric  acid  formed  in  the  burning  of  the  proteids 
in  the  organism,  which  must  be  then  taken  from  the  tissues.  In 
accordance  with  this  view,  Bunge  and  Lunin ''  also  found  on 
experimenting  on  mice  that  animals  which  received  nearly  ash-free 
food  with  the  addition  of  sodium  carbonate  were  kept  alive  twice  as 
long  as  animals  which  had  the  same  food  without  the  addition  of 
sodium  carbonate.  Special  experiments  also  show  that  the  carbon- 
ate cannot  be  replaced  by  au  equivalent  amount  of  sodium  chloride, 
and  that  to  all  appearances  it  acts  by  combining  with  the  acids 
formed  in  the  body.  The  addition  of  alkali  carbonate  to  the  other- 
wise nearly  ash-free  food  may  indeed  delay  death,  but  cannot 
prevent  it,  and  even  in  the  presence  of  the  necessary  amount  of 
bases  death  results  for  lack  of  mineral  substances  in  the  food. 

In  the  above  series  of  experiments  made  by  Bunge  the  food  of 
the  animal  consisted  of  casein,  milk-fat,  and  cane-sugar.  While 
milk  alone  was  an  adequate  and  sufficient  food  for  the  animal, 
Bunge  found  that  the  animal  could  not  be  kept  alive  longer  by  food 
consisting  of  the  above  constituents  of  milk  and  cane-sugar  with 
the  addition  of  all  the  mineral  substances  of  milk,  than  with  the 
food  mentioned  in  the  above  experiments  with  the  addition  of  alkali 
carbonate.  The  question  whether  this  result  is  to  be  explained  by 
the  fact  that  the  mineral  bodies  of  milk  are  chemically  combined 
with  the  organic  constituents  of  the  same  and  can  be  assimilated 
only  in  such  combinations,  or  whether  it  depends  on  other  condi- 
tions, Bunge  leaves  undecided.  These  observations,  however,  show 
how  difficult  it  is  to  draw  positive  conclusions  from  experiments 
made  thus  far  with  food  poor  in  salts.  Further  investigations  on 
this  subject  seem  to  be  necessary. 

With  an  insufficient  supply  of  chlorides  with  the  food  the  elimi- 
nation of  chlorine  by  the  urine  decreases  constantly,  and  at  last  it 
may  stop  entirely  while  the  tissues  still  persistently  retain  the  chlo- 
rides.    These  last  are,  at  least  in  part,  combined  in  the  body  with 

>  Lelirbucli  d.  physiol.  Chem.,  1.  Aufl.,  S.  103. 
'  Ibid.,  and  Zeitschr.  f.  physiol.  Chem.,  Bd.  5. 


628  METABOLISM. 

the  organic  substances  which  retain  them.  The  great  importance 
of  such  a  retention  of  chlorides  by  the  tissues  is  apparent  if  we  bear 
in  mind  that  the  NaCl  is  not  only  a  solvent  for  certain  albuminous, 
bodies,  or  a  material  for  the  elaboration  of  the  gastric  juice,  but 
that  it  is  also  of  the  greatest  importance  as  a  so-called  indifferent 
salt  for  the  preservation  of  the  normal  consistency  and  the  physio- 
logical imbibition  relation  of  the  tissues. 

If  there  be  a  lack  of  sodium  as  compared  with  potassium,  also  if 
there  be  an  excess  of  potassium  compounds  in  any  other  form  than 
KCl,  the  potassium  combinations  are  replaced  in  the  organism  by 
JSTaCl,  so  that  new  potassium  and  sodium  compounds  are  produced 
which  are  voided  with  the  urine.  The  organism  becomes  poorer  in 
NaCl,  which  therefore  must  be  taken  in  greater  amounts  from  th& 
outside  (Btjnge).  This  occurs  habitually  in  herbivora,  and  in  man 
with  vegetable  food  rich  in  potash.  For  human  beings,  and  espe- 
cially for  the  poorer  classes  of  people  who  live  chiefly  on  potatoes 
and  foods  rich  in  potash,  common  salt  is,  under  these  circumstances, 
not  only  a  condiment,  but  a  necessary  addition  to  the  food 
(Bungb'). 

Lack  of  Alkali  Carbonates  or  Bases  in  the  Food.  The  chemical 
processes  in  the  organism  are  dependent  upon  the  presence  of  alka- 
line-reacting tissue-fluids,  whose  alkaline  reaction  is  due  to  alkali 
carbonates.  The  alkali  carbonates  are  also  of  great  importance  not 
only  as  a  solvent  for  certain  proteid  bodies  and  as  constituents  of 
certain  secretions,  such  as  the  pancreatic  and  intestinal  juices,  but 
they  are  also  a  means  of  transportation  of  the  carbon  dioxide  in  the 
blood.  It  is  therefore  easy  to  understand  that  a  decrease  below  a 
certain  point  in  the  quantity  of  alkali  carbonate  must  endanger  life. 
Such  a  decrease  not  only  occurs  with  lack  of  bases  in  the  food  which 
accelerates  death  by  a  relatively  too  great  production  of  acids  by  the 
burning  of  the  proteids  (see  above:  Buhge  and  Lunin),  but  it  also 
occurs  when  an  animal  is  given  dilute  mineral  acids  for  a  certain 
time.  In  herbivora  the  fixed  alkalies  of  the  tissues  combine  with 
the  mineral  acids,  and  the  animal  succumbs  after  a  time.  In 
carnivora  (and  in  man)  the  bases  of  the  tissues  are  obstinately 
retained;  the  mineral  acids  unite  with  the  ammonia  produced  by 
the  decomposition  of  the  proteids  or  their  cleavage  products,  and 
carnivora  can  therefore  be  kept  alive  for  a  longer  time. 

Lack  of  Earthy  Pliosphates.     With  the  exception  of  the  impor- 
'  Zeitschr.  f.  Biolog-ie,  Bd.  9. 


LACK  OF  IRON.  629, 

taace  of  the  alkaline  earths  as  carbonates  and  principally  as  phos- 
phates in  the  physical  composition  of  certain  structures,  such  as  the 
bones  and  teeth,  their  physiological  importance  is  nearly  unknown. 
The  occurrence  of  earthy  phosphates  in  all  proteids,  and  the  great 
importance  of  the  earthy  phosphates  in  the  passage  of  the  proteids 
from  a  soluble  to  a  coagulable  and  solid  state,  make  it  j^robable  that 
the  earthy  phosphates  play  an  important  part  in  the  organization  of 
the  proteids.  The  action  which  an  insufficient  supply  of  alkali- 
earths  with  the  food  causes  is  connected  with  the  interesting  ques- 
tion as  to  the  effect  of  this  lack  upon  the  bony  structure.  This 
action,  as  well  as  the  various  results  obtained  by  experiments  on 
young  and  old  animals,  has  already  been  spoken  of  in  Ciiap.  X,  to 
"which  we  refer  the  reader. 

Lack  of  Iro7i.  As  iron  is  an  integral  constituent  of  haemoglobin, 
indispensable  for  the  introduction  of  oxygen,  so  iron  is  an  indispen- 
sable constituent  of  the  food.  In  iron  starvation  iron  is  continually 
eliminated,  even  though  in  diminished  amounts  (Dietl,'  v.  Ho8- 
Lix,*  and  others).  From  the  observations  of  v.  Hoslin  on  dogs 
it  seems  that  an  inadequate  supply  of  iron  with  the  food  causes  an 
insufficient  formation  of  haemoglobin.  A  special  result  of  the  lack 
of  iron  is  chlorosis,  which  the  physician  has  often  to  contend  with 
and  whose  origin  is  not  really  a  lack  of  iron  in  the  food,  but  more 
likely  an  incomplete  assimilation  and  absorption  of  the  foods  contain- 
ing iron  (Buxge).  The  iron-salts  as  such  seem  not  to  be  absorbed 
at  all  in  the  intestinal  canal,  or  only  to  a  very  small  extent,  so  that 
it  is  questionable  whether  their  absorption  has  any  importance 
worth  noting.  It  seems  more  probable  that  the  absorption  of  iron 
from  the  food  takes  place  in  the  form  of  protein  bodies  (nucleo- 
alburain)  containing  iron  (Bujstge)  ;  and  the  importance  of  the  iron- 
salts  in  preventing  the  lack  of  haemoglobin  consists  chiefly,  accord- 
ing to  BuNGE,'  in  that  these  salts  counteract  the  decomposition  in 
the  intestine  of  the  protein  bodies  containing  iron,  with  a  splitting 
off  of  iron  as  iron  sulphide. 

In  the  absence  of  proteid  bodies  in  the  food  the  organism  must 
nourish  itself  by  its  own  proteid  substances,  and  on  such  nutrition 
it  must  earlier  or  later  succumb.  By  the  exclusive  administration 
ci  fat  and  carbohydrates  the  consumption  of  proteids  in  these  cases 

'  Wien.  Sitzungsber.,  Bd.  71,  Abth.  3,  1875. 

»  Zeitschr.  f.  Biologie,  Bd.  18. 

»  Zeitschr.  f.  pbv.siol.  Cliem.,  Bd.  9. 


630  METABOLISM. 

is  reduced,  for  by  an  exclusive  fat  and  carbohydrate  diet  the  meta- 
bolism of  proteids  may  indeed  be  smaller  than  in  complete  starvation 
(Hieschfeld/  Kumagawa,''  Klemperee,'  Muistk/  Eosenheim/ 
and  others).  In  conformity  with  this  the  animal  may  be  kept  alive 
longer  by  food  containing  only  non-nitrogenous  bodies  than  in 
complete  starvation. 

The  absence  of  fats  and  carholiydrates  in  the  food  affect  carniv- 
ora  and  herbivora  somewhat  differently.  It  is  unknown  whether 
carnivora  can  be  kept  alive  for  any  length  of  time  by  food  entirely 
free  from  fat  and  carbohydrates.  But  it  has  been  positively  demon- 
strated that  they  can  be  kept  alive  a  long  time  by  feeding  exclusively 
with  meat  freed  as  much  as  possible  from  visible  fat  (Pfluger"). 
Human  beings  and  herbivora,  on  the  contrary,  cannot  live  for  any 
length  of  time  on  such  food.  On  one  side  they  lose  the  property 
of  digesting  and  assimilating  the  necessarily  large  amounts  of  meat, 
and  on  the  other  a  distaste  for  large  quantities  of  meat  or  proteids, 
soon  appears. 

IV.  Metabolism  with  Various  Foods. 

For  the  carnivora,  as  above  stated,  meat  as  poor  as  possible  in 
fat  may  be  a  complete  and  sufficient  food.  As  the  proteids  more- 
over take  a  special  place  among  the  organic  nutritive  bodies  by  the 
quantity  of  nitrogen  they  contain,  it  is  proper  that  we  first  describe 
the  exchange  of  material  with  an  exclusively  meat  diet. 

Metabolism  with  food  rich  in  proteids,  or  feeding  only  with 
meat  as  poor  in  fat  as  possible. 

By  aa  increased  supply  of  proteids  the  metabolization  of  proteids 
and  the  elimination  of  nitrogen  is  increased,  and  this  in  proportion 
to  the  supply  of  proteids. 

If  a  certain  quantity  of  meat  has  oeen  given  as  food  daily  to  car- 
nivora and  the  quantity  is  suddenly  increased,  an  increased  meta- 
bolism of  proteids  or  an  increase  in  the  quantity  of  nitrogen  elimi- 
nated is  the  result.  If  we  feed  the  animal  daily  for  a  certain  time 
with  larger  quantities  of  the  same  meat,  we  find  that  a  part  of  tlie 
proteids  accumulates  in  the  body,  but  this  part  decreases  from  daj 

'  Vircliow's  Arch.,  Bd.  114. 
5  Ibid.,  Bd.  116. 

*  Zeitscbr.  f.  klin.  Med.,  Bd.  16. 

*  Du  Bois-Reymond's  Arch.,  1891. 

^Ibid  ,  S.  341  and  Pfltlger's  Arch.,  Bd.  54. 

*  Pfltlger's  Arch.,  Bd.  50. 


WITH  FOOD  men  /y  proteids.  631 

to  day,  while  there  is  a  correspouding  daily  increase  in  the  elimina- 
tion of  nitrogen.  In  this  way  a  nitrogenous  equilibrium  is  estab- 
lished, that  is,  the  total  quantity  of  nitrogen  eliminated  is  equal  to 
the  quantity  of  nitrogen  in  the  absorbed  proteids  or  meat.  If,  on 
the  contrary,  an  animal  which  is  in  nitrogenous  equilibrium,  having 
been  fed  on  large  quantities  of  meat,  is  suddenly  fed  with  a  small 
quantity  of  meat  per  day,  then  the  animal  gives  up  its  own  bodily 
proteids,  the  amount  decreasing  from  day  to  day.  The  elimination 
of  nitrogen  and  the  metabolism  of  proteids  decrease  constantly,  and 
the  animal  may  in  tbis  case  also  pass  into  nitrogenous  equilibrium 
or  nearly  into  this  condition.  These  relations  are  illustrated  by 
the  following  table  (Voit  ') : 

Table  V. 

Grms.  of  Meat  in  the  Food  per  Day. 

Before  the  Test.      During  the  Test. 

1 500  1500 

2 1500  1000 

Grms.  of  Flesh  metabolized  in  Body  per  Day. 


1  2  3  4  5  6  T 

1223         1310         1390        1410        1440        1450        1500 
1153         1086         1088        1080        1027 

In  the  first  case  (1)  the  metabolism  of  flesh  before  the  beginning 
of  the  actual  experiment  on  feeding  with  500  grms.  meat  was  447 
grms.,  and  it  increased  considerably  on  the  first  day  of  the  experi- 
ment, after  feeding  on  1500  grms.  meat.  In  the  second  case  (2), 
in  which  the  animal  was  previously  in  nitrogenous  equilibrium  with 
1500  grms.  meat,  the  metabolism  of  flesh  on  the  first  day  of  the 
experiment,  with  only  1000  grms.  meat,  decreased  considerably,  and 
on  the  fifth  day  a  nearly  nitrogenous  equilibrium  was  obtained. 
During  this  time  the  animal  gave  up  daily  some  of  its  own  proteids. 
Between  that  point  below  which  the  animal  loses  from  its  own 
weight  and  the  maximum,  which  seems  to  be  dependent  upon  the 
digestive  and  assimilative  capacity  of  the  intestinal  canal,  a  carniv- 
ora  may  be  kept  in  nitrogenous  equilibrium  with  varying  quantities 
of  proteids  in  the  food. 

The  supply  of  proteids,  as  well  as  the  proteid  condition  of  the 
body,  affects  the  extent  of  the  proteid  metabolism.  A  body  which 
has  become  rich  in  proteids  by  a  previous  abundant  meat  diet  must, 

'  Hermaan's  Handbucb.  Bd.  6,  Thl.  1,  S.  110. 


032  METABOLISM. 

to  prevent  a  loss  of  proteids,  take  up  more  proteid  with  the  food 
than  a  body  poor  in  proteids. 

Pettexkofer  and  Yoit  have  made  investigations  on  the  7neta- 
boUsm  of  fat  with  an  exclusively  albuminous  diet.  These  investi- 
£-ations  have  shown  that  by  increasing  the  quantity  of  proteids 
in  the  food  the  daily  metabolism  of  fat  decreases,  and  they  have 
drawn  the  conclusion  from  these  experiments,  as  detailed  in 
Chapter  X,  that  even  a  formation  of  fat  may  take  place  under  these 
circumstances.  The  objections  presented  by  Pfluger  against 
these  experiments  are  also  mentioned  in  this  chapter,  and  Kuma- 
GAWA '  has  recently  published  a  new  and  important  investigation 
on  this  subject. 

KuMAGAWA  caused  two  dogs  of  the  same  litter  to  fast  for 
over  20  days  in  order  to  remove  the  body  fat.  One  of  the  dogs 
(the  control  dog)  was  then  killed  and  the  total  fat  determined. 
The  other  animal  received  meat  poor  in  fat  (with  a  kuown 
quantity  of  ether  extractives,  glycogen,  nitrogen,  water,  and  ash) 
in  as  large  quantities  as  it  could  endure,  and  this  feeding  with  meat 
was  continued  (about  50  days)  until  a  marked  increase  in  bodily 
weight  had  taken  place.  The  quantity  of  nitrogen  in  the  urine  and 
faeces  daring  this  period  was  also  determined,  and  finally  the  animal 
was  killed  and  the  total  quantity  of  fat  determined.  The  results 
were  that  the  fat  formed  during  the  period  of  feeding  corresponded 
exactly  with  the  quantity  existing  in  the  meat  fed  to  the  animal 
and  formed  from  the  glycogen  of  the  meat.  In  this  case  no  fat 
formation  from  proteid  was  found,  and  according  to  Kumagawa 
the  animal  body  under  normal  circumstances  has  no  ability  of 
forming  fat  from  proteid. 

According  to  Pfluger's  doctrine,  which  has  received  support 
from  these  investigations,  the  proteid  can  influence  the  formation  of 
fat  only  in  an  indirect  way,  namely,  in  that  it  is  consumed  instead 
of  the  non-nitrogenous  bodies  and  hence  the  fat  and  fat-forming 
carbohydrates  are  spared.  If  sufficient  proteid  is  introduced  in  the 
food  to  satisfy  the  total  nutritive  requirements,  then  the  decomposi- 
tion of  fat  stops;  and  if  also  non-nitrogenous  food  is  taken  at  the 
same  time,  this  is  not  consumed,  but  is  stored  up  in  the  animal 
body,  the  fats  as  such,  and  the  carbohydrates  at  least  in  great  part 
as  fat. 

'  Zur  Frage  der  Fettbildung  aus  Eiweiss  im  Thierkorper.  Mittheil.  der 
med.  Fakultat  der  kaiserl,  Japan.  Universitat  zu  Tokio,  Bd.  3,  No.  1,  1894. 


TISSUE  AND   CIRCULATING   PROTEIDS.  633 

Pfluger  calls  the  "  nutritive  requirement  "  as  tlie  smallest 
quantity  of  lean  meat  which  produces  nitrogenous  equilibrium 
without  causing  any  decomposition  of  fat  or  carbohydrates.  At 
rest  and  at  an  average  temperature  it  is  found  for  dogs  to  be  2.073 
grms.  nitrogen  (in  meat  fed)  per  kilo  of  flesh  weight  (not  bodily 
weight,  as  the  fat,  which  often  forms  a  considerable  fraction  of  the 
weight  of  the  body,  cannot  as  it  were  be  used  as  dead  measure). 
Even  when  the  supply  of  proteid  is  in  excess  of  the  nutritive 
requirements,  Pfluger  has  found  that  the  proteid  metabolism 
increases  with  an  increased  supply  until  the  limit  of  digestive  power 
is  reached,  which  limit  is  about  2600  grms.  meat  with  a  dog  weigh- 
ing 30  kilos.  In  these  experiments  of  Pfluger's  all  of  the  excess 
of  proteid  introduced  was  not  completely  decomposed,  but  a  part 
was  retained  by  the  body.  Pfluger  therefore  defends  the  proposi- 
tion "  that  an  exclusive  proteid  supply,  without  fat  or  carbo- 
hydrate, does  not  exclude  a  proteid  fattening." 

From  what  has  been  said  on  proteid  metabolism  in  starvation 
and  with  one-sided  proteid  food  it  follows  that  the  proteid  meta- 
bolism in  the  animal  body  never  stops,  that  the  extent  is  dependent 
in  the  first  place  upon  the  extent  of  proteid  supply,  and  that  the 
animal  body  has  the  property,  within  wide  limits,  of  accommodating 
the  proteid  metabolism  to  the  proteid  supply. 

These  and  certain  other  peculiarities  of  proteid  metabolism  have 
led  VoiT  to  the  view  that  all  proteids  in  the  body  are  not  decom- 
posed with  the  same  ease.  A^oit  differentiates  the  proteids  fixed  in 
the  tissue-elements,  so-called  organized  proteids,  tissue-proteids, 
from  those  proteids  which  circulate  with  the  fluids  in  the  body  and 
its  tissues  and  which  are  taken  up  by  the  living  cells  of  the  tissues 
from  the  interstitial  fluids  washing  them  and  destroyed.  These 
circulating  proteids  are,  according  to  V^oit,  more  easily  and  quickly 
destroyed  than  the  tissue-proteids.  When,  therefore,  in  a  fasting 
animal  which  has  been  previously  fed  with  meat  an  abundant  and 
quickly  decreasing  decomposition  of  proteids  takes  place,  while  in 
the  further  course  of  starvation  this  proteid  metabolism  becomes 
less  and  more  uniform,  this  depends  upon  the  fact  that  the  supply 
of  circulating  proteids  is  destroyed  chiefly  in  the  first  days  of  starva- 
tion and  the  tissue-proteids  in  the  last  days. 

The  tissue-elements  constitute  an  apparatus  of  a  relatively  stable 
nature,  which  has  the  power  of  taking  proteids  from  the  fluids 
washing  the  tissues  and  digesting  them,  while  a  few  proteids,  the 


634  METABOLISM. 

tissue-pro teids,  are  ordinarily  disorganized  to  only  a  small  extent, 
about  Ifo  daily  (Voit).  By  an  increased  supply  of  proteids  the 
activity  of  the  cells  and  their  ability  to  decompose  nutritive  proteids 
is  also  increased  to  a  certain  degree.  When  nitrogenous  equilibrium 
is  obtained  after  increased  supply  of  proteids,  it  denotes  that  the 
decomposing  power  of  the  cells  for  proteids  has  increased  so  that 
the  same  quantity  of  proteids  is  metabolized  as  is  supplied  to  the 
body.  If  the  proteid  metabolism  is  decreased  by  the  simultaneous 
administration  of  other  non-nitrogenous  foods  (see  below),  a  part  of 
the  circulating  proteids  may  have  time  to  become  fixed  and  organ- 
ized by  the  tissues,  and  in  this  way  the  mass  of  the  flesh  of  the  body 
increases.  During  starvation  or  with  lack  of  proteids  in  the  food 
the  reverse  takes  place,  for  a  part  of  the  tissue  proteids  is  converted 
into  circulating  proteids  which  are  metabolized,  and  in  this  case  the 
flesh  of  the  body  decreases. 

Voit's  doctrine  has  been  severely  attacked  by  Pflugek.' 
Pflugek  states,  basing  his  statement  on  an  investigation  made  by 
one  of  his  pupils,  Schondokff,*  that  the  extent  of  proteid  destruc- 
tion is  not  dependent  upon  the  quantity  of  circulating  proteids,  but 
upon  the  nutritive  condition  of  the  cells  for  the  time  being — a  view 
which  is  not  very  contradictory  of  Voit's  doctrine,  if  the  author 
does  not  misunderstand  Pfluger's  statement,  Voit'  has,  as  is 
known,  stated  that  the  conditions  of  the  destruction  of  substances 
in  the  body  exist  in  the  cells,  and  also  that  the  circulating  proteid, 
likewise  according  to  Voit,  is  first  metabolized  after  having  been 
taken  up  by  the  cells  from  the  fluids  washing  them.  The  organized 
proteid,  which  is  fixed  by  the  cells  and  has  become  a  part  of  the 
same,  is  destroyed  less  readily,  according  to  Voit,  than  the  proteid 
taken  up  by  the  cells  from  the  nutritive  fluid,  which  serves  as 
material  for  the  chemical  construction  of  the  very  much  more  com- 
plicated organized  proteids.  This  nutritive  proteid,  which  circu- 
lates with  the  fluids  before  it  is  taken  up  by  the  cells,  and  which 
can  exist  in  store  in  the  cells  as  well  as  in  the  fluids,  which  corre- 
sponds to  Voit's  view,  has  been  called  circulating  proteid  or  supply 
proteid  by  him.  It  is  clear  that  these  names  may  lead  to  misunder- 
standing, and  therefore  too  much  stress  should  not  be  put  on  them. 
The  most  essential  part  of  Voit's  doctrine  is  the  supposition  that 

'  Pfluger's  Arcli. ,  Bd.  54. 

''Ibid.,  Bd.  54. 

*  Zeitschr.  f.  Biologie,  Bd.  11. 


NUTRITIVE    VALUE  OF  GELATIN.  635 

the  food  proteid  of  the  cells  is  more  easily  destroyed  than  the 
organized,  real  protoplasmic  proteid,  and  this  statement  can  hardly, 
for  the  present,  be  considered  as  refuted  or  exactly  proven. 

This  question  is  intimately  connected  with  another,  namely, 
whether  the  food  proteids  taken  np  by  the  cells  are  metabolized  as 
snch  or  whether  they  are  first  organized.  The  investigations  of 
Paxum  '  and  Falck  '  on  the  transitory  progress  of  the  elimination 
of  iirea  after  a  meal  rich  in  proteids  throws  light  on  this  question. 
From  the  investigations  on  a  dog  it  was  found  that  the  elimination 
of  urea  increases  almost  immediately  after  a  meal  rich  in  proteids, 
and  that  it  reaches  its  maximum  in  about  six  hours,  when  about  one 
half  of  the  quantity  of  nitrogen  corresponding  to  the  administered 
proteids  is  eliminated.  If  we  also  recollect  that,  according  to  an 
observation  of  Schmidt-Mulheiji  '  on  a  dog,  about  olfo  of  the 
given  proteids  are  absorbed  in  the  first  two  hours  after  the  meal  and 
about  59'tf  in  the  course  of  the  first  six  hours,  we  may  then  infer 
that  the  increased  elimination  of  nitrogen  after  a  meal  is  due  to  a 
metabolization  of  the  digested  and  assimilated  proteids  of  the  food 
not  previously  organized.  If  we  admit  that  the  metabolized  proteid 
must  have  been  organized,  then  the  greatly  increased  elimination  of 
nitrogen  after  a  meal  rich  in  proteids  supposes  a  far  more  rapid  and 
comprehensive  destruction  and  reconstruction  of  the  tissues  than 
has  been  generally  admitted  and  not  j)roven. 

It  has  been  stated  above  that  other  foods  may  decrease  the 
metabolism  of  proteids.  Gelatin  is  such  a  food.  Gelatin  and  the 
gelatin-formers  do  not  seem  to  be  converted  into  proteid  in  the 
body,  and  this  last  cannot  be  entirely  replaced  by  gelatin  in  the 
food.  For  example,  if  a  dog  is  fed  on  gelatin  and  fat,  its  body 
sustains  a  loss  of  proteids  even  when  the  quantity  of  gelatin  is  so 
large  that  the  animal,  with  an  amount  of  fat  and  meat  containing 
just  the  same  quantity  of  nitrogen  as  the  gelatin  in  question,  may 
remain  in  nitrogenous  equilibrium.  On  the  other  hand,  gelatin,  as 
VoiT,*  Paxum  and  Oerum  '  have  shown,  has  a  great  value  as  a 
means  of  sparing  the  proteids,  and  it  may  decrease  the  metabolism 
of  proteids  to  a  still  greater  extent  than  fats  and  carbohydrates. 

'  Nord.  med.  Arkiv.,  Bd.  6. 

'  Cited  from  Voit  in  Hermann's  Handbuch.  Bd.  6.,  Thl.  1,  S.  107. 

^  Du  Bois-Reymond's  Arch.,  1879. 

«L.  c,  S.  123. 

*  Nord.  med.  Arkiv..  Bd.  11 


(536  METABOLISM. 

This  is  apparent  from  the  following  summary  of  Voit's  experiments 
on  a  dog: 

Table  VI. 
Food  per  Day.  Flesh. 


Meat. 

Gelatin. 

Fat. 

Sugar. 

400 

0 

200 

0 

400 

0 

0 

250 

400 

200 

0 

0 

Metabolized.  On  tlie  Body. 

450  -  50 

439  -  39 

256  +  44 


I.  MuNK '  has  later  arrived  at  similar  results  by  means  of  more 
decisive  experiments.  lie  found  in  dogs  that  on  a  mixed  diet 
which  contained  3.7  grms.  proteid  per  kilo  of  body,  of  which  hardly 
8,6  grms.  was  metabolized,  nearly  f  could  be  replaced  by  gelatin. 
The  same  dog  metabolized  on  the  second  starvation  day  three  times 
as  much  proteid  as  with  the  gelatin  feeding.  Munk  states  also  that 
gelatin  has  a  much  greater  sparing  action  on  proteids  than  the  fat 
or  the  carbohydrates. 

This  ability  of  gelatin  to  spare  the  proteids  is  explained  by 
VoiT  by  the  statement  that  the  gelatin  is  decomposed  instead  of  a 
part  of  the  circulating  proteids,  whereby  a  part  of  this  last  may  be 
organized. 

Gelatin  may  also  decrease  somewhat  the  consumption  of  fat, 
although  it  is  of  less  value  in  this  respect  than  the  carbohydrates. 

The  question  of  nutritive  value  oi  pepto7ies  stands  in  close  rela- 
tion to  the  nutritive  value  of  the  proteids  and  gelatin.  The  early 
investigations  made  by  Maly,  Plos'z  and  Gyeegtat,  and  Adam- 
KiEWicz"  have  led  to  the  conclusion  that  an  animal  with  food 
which  contains  no  proteids  besides  peptones  may  not  only  preserve 
its  nitrogenous  equilibrium,  but  its  proteid  condition  may  even 
increase.  According  to  recent,  more  exact  investigations  of 
PoLLiTZEK,  ZuNTZ,"  and  MuNK  ^  the  albumoses  and  peptones  have 
the  same  nutritive  value  as  proteids,  at  least  in  short  experiments. 
According  to  Pollitzer  this  is  true  for  different  albumoses  as  well 
as  for  true  peptone.  Contrary  to  this  view  Voit*  is  of  the  opinion 
that  the  albumoses  and  peptones  can  replace  the  proteids  only  for  a 
short  time,  not  indefinitely.  According  to  Voit  the  albumoses 
and  peptones,  like  gelatin,  may,  by  their  ability  to  spare  proteid, 

>  Pfluger's  Arch.,  Bd.  58. 
'  Cited  from  page  329. 

3  See  Maly's  Jabresber  ,  Bd.  19,  S.  353  u.  402. 

4  L.  c,  S.  394. 


WITH  MIXED  DTET.  637 

entirely  or  nearly  arrest  the  consamptiou  of  proteid,  but  cannot 
pass  into  proteid. 

From  experiments  made  by  Weiske  '  and  others  on  herbivora 
it  appears  that  asparagin  may  spare  proteid  in  such  animals.  In 
carnivora  (I.  Munk  ')  and  in  mice  ( Voit  and  Politis  ')  it  was 
found  that  asparagin  does  not  seem  to  have  any  sparing  action  on 
the  proteids/  or  only  a  very  slight  action.  It  is  not  known  how  it 
acts  in  man. 

Metabolism  on  a  Diet  consisting  of  Proteid,  with  Fat  and 
Carbohydrate.  Fat  cannot  arrest  or  prevent  the  metabolism  of  pro- 
teids;  bat  it  can  decrease  it,  and  so  spare  the  proteids.  This  is 
apparent  from  the  following  table  of  Voit.^  A  is  the  average  for 
three  days,  and  B  for  six  days. 

Table  VII. 

Food.  Flesh. 


Meat.  Fat.  Metabolized.       On  the  Body. 

A 1500  0  1512  -  12 

B 1500  150  1474  +24 

According  to  VoiT  the  adipose  tissue  of  the  body  acts  like  the 
food -fat,  and  the  proteid-sparing  effect  of  the  former  may  be  added 
to  that  of  the  latter,  so  that  a  body  rich  in  fat  may  not  only  remain 
in  nitrogenous  equilibrium,  but  may  even  add  to  the  store  of  bodily 
proteids,  while  in  a  lean  body  with  the  same  food  containing  the 
same  amount  of  proteids  and  fat  there  would  be  a  loss  of  proteids. 
In  a  body  rich  in  fat  a  greater  quantity  of  proteids  is  protected 
from  metabolism  by  a  certain  quantity  of  fat  than  in  a  lean  body. 

Because  of  the  sparing  action  of  fats  an  animal  by  the  addition 
of  fat  to  its  food  may,  as  is  apparent  from  the  tables,  increase  its 
proteid  condition  with  a  quantity  of  meat  which  is  insufficient  to 
preserve  nitrogenous  equilibrium. 

Like  the  fats  the  carbohydrates  have  a  sparing  action  on  the 
proteids.  By  the  addition  of  carbohydrates  to  the  food  the  carni- 
vor  not  only  remains  in  nitrogenous  equilibrium,  but  the  same 
quantity  of  meat  which  in  itself  is  insufficient  and  which  without 

'  Zeitscbr.  f.  Biologie,  Bdd.  15  u.  17  and  Centralbl.  f.  d.  med.  Wissenscli., 
1890,  S.  945. 

'  Vircbow's  Arch.,  Bdd.  94  u.  98. 

3  Zeitscbr.  f.  Biologie,  Bd.  28. 

•  See  Mantbner,  ibid.,  Bd.  28,  and  Gabriel,  ibid.,  Bd.  29,  and  Voit,  ibid.,  S. 
125. 

'See  Voit  in  Hermann's  Handbucb,  Bd.  6,  S.  130. 


(538  METABOLISM. 

carbohydrates  would  cause  a  loss  of  weight  in  the  body  may  with 
the  addition  of  carbohydrates  produce  a  deposit  of  proteids.  This 
is  apparent  from  the  following  table  ' : 

Table  VIII. 
Food.  Flesh. 


Meat. 

Fat. 

Sugar. 

Starch. 

Metabolized. 

On  the  Body. 

500 

250 

558 

-  58 

500 

300 

466 

+  34 

500 

200 

505 

-     5 

800 

250 

745 

+  55 

800 

200 

773 

+  27 

2000 

200-300 

1792 

+208 

2000 

250 

1883 

+117 

The  sparing  of  proteid  by  carbohydrate  is  greater,  as  shown  by 
the  table,  than  by  fats.  According  to  Voit  the  first  is  on  an 
average  9^  and  the  other  7^  of  the  administered  proteid,  without  a 
previous  addition  of  non-nitrogenous  bodies.  Increasing  quantities 
of  carbohydrates  in  the  food  decrease  the  proteid  metabolism  more 
regularly  and  constantly  than  increasing  quantities  of  fat. 

The  law  as  to  the  increased  proteii  metabolism  with  increased 
proteid  supply  applies  also  to  food  consisting  of  proteid  with  fat  and 
carbohydrates.  In  these  cases  the  body  tries  to  adapt  its  proteid 
metabolism  to  the  supply;  and  when  the  daily  calorie  supply  is 
completely  covered  by  the  food,  the  organism  can,  within  wide 
limits,  be  in  nitrogenous  equilibrium  with  different  quantities  of 
proteid. 

The  upper  limit  to  the  possible  proteid  metabolism  per  kilo  and 
per  day  has  only  been  determined  for  herbivora.  It  is  not  known  for 
human  beings,  and  its  determination  is  from  a  practical  standpoint 
of  secondary  importance.  What  is  more  important  is  to  ascertain 
the  lower  limit,  and  on  this  subject  we  have  several  investigations 
on  man  as  well  as  animals  by  Hirschfeld,  Kumagawa,  Klem- 
PERER,  MuNK,  Rosenheim,'-'  and  others.  It  follows  from  these 
investigations  that  the  lower  limit  of  proteid  needed  for  human 
beings  for  a  week  or  less  is  about  BO-40  grms.  proteid  or  0.4-0.6 
grm.  per  kilo  with  a  boJy  of  average  weight,  v.  Noorden'  con- 
siders 0.6  grm.  proteid  (assimilated  proteid)  per  kilo  and  per  day  as 
the  lower  limit.  The  above-mentioned  figures  are  only  valid  for 
short   series   of   experiments;   still   we   have   the   observations   of 

'  Voit  in  Hermann's  Handbncli,  Bd.  6,  S.  143. 

'  See  foot-notes  1-5,  page  630 

»  Grundriss  einer  Method  ik  der  Stoffwechseluntersuchungen.    Berlin,  1892. 


WITH  MIXED  DIET.  639 

E.  VoiT  and  Constantinidi  '  on  the  diet  of  a  vegetarian  in  which 
the  proteid  condition  was  kept  nearly  but  not  completely  maintained 
with  about  0.6  grm.  proteid  per  kilo. 

According  to  Voit's  normal  figures,  which  will  be  spoken  of 
below  for  the  nutritive  need  of  man,  an  average  working  man  of 
about  70  kilos  weight  on  a  mixed  diet  requires  about  40  calories  per 
kilo  (two  calories  or  net  calories,  namely,  the  combustion  value  of 
the  assimilated  foods).  In  the  above  experiments  with  food  very 
poor  in  proteid  the  demand  for  calories  was  considerably  greater,  as 
for  instance  in  certain  cases  it  was  51  (Kcmagawa)  or  even  78.5 
calories  (Klemperer).  It  therefore  seems  as  if  the  above  very  low 
supply  of  proteid  was  only  possible  with  great  waste  of  non-nitrogen- 
ous food  ;  but  in  opposition  to  this  we  must  recall  that  in  Voit  and 
CoxsTAXTixiDi's  experiments  on  the  vegetarian,  who  for  years  was 
used  to  a  food  very  poor  in  proteid  and  rich  in  carbohydrate,  the 
calories  only  amounted  to  43.7  per  kilo.  It  is  an  open  question 
how  a  nitrogenous  equilibrium  can  exist  also  on  a  diet  very  poor  in 
nitrogen,  when  the  need  of  calories  is  only  just  covered  by  the  total 
supply. 

In  MrxK's  and  Eoseniieim's  experiments  on  dogs  the  food  poor 
in  proteids  must  have  raised  the  total  supply  of  calories  consider- 
ably. These  experiments  also  teach  that  in  dogs  the  continuous 
administration  for  a  long  time  of  food  poor  in  proteid  has  an  action 
on  the  health  of  the  animal  and  may  even  cause  death.  In  the 
experiments  recently  published  by  Eosenheim,  which  extended  over 
two  months,  2  grms.  proteid  per  kilo  of  body  was  not  sufficient  to 
keep  the  animal  healthy  although  the  heat  value  of  the  food  taken 
up  amounted  to  110  calories  per  kilo. 

The  very  important  question  as  to  the  conditions  for  the  deposi- 
tion of  fat  and  flesh  on  the  body  stands  in  close  connection  to  what 
has  just  been  said  in  regard  to  foods  consisting  of  proteid  and  non- 
nitrogenous  food-stuffs.  In  this  connection  we  must  recall  in  the 
first  place  that  all  fattening  presupposes  an  overfeeding,  i.e.,  a 
supply  of  food-stuffs  which  is  greater  than  that  metabolized  at  the 
same  time. 

In  carnivora,  as  shown  by  the  investigations  of  Voit  and 
Pfluger,  a  very  inconsiderable  metabolized  proteid,  in  proportion 
to  the  deposition  of  flesh,  may  take  place  with  exclusive  meat  food. 
In  man  and  herbivora,  on  the  contrary,  the  demand  for  calories 

'  C.  Voit,  Zeitscbr.  f.  Biologie,  Bd.  25. 


(>4:0 


METABOLISM. 


may  not  be  covered  by  proteid  alone,  and  the  question  as  to  the  con- 
ditions of  fattening  with  a  mixed  diet  is  of  importance. 

These  conditions  have  also  been  studied  on  carnivora,  and  here, 
as  VoiT  has  shown,  the  relationship  between  proteid  and  fat  (and 
carbohydrates)  is  of  great  importance.  If  considerable  fat  is  given 
in  proportion  to  the  proteid  of  the  food,  as  with  average  quantities 
of  meat  with  considerable  addition  of  fat,  then  nitrogenous  equilib- 
rium is  only  slowly  attained  and  the  daily  deposit  of  flesh,  though 
not  large,  but  quite  constant,  may  be  considerable  in  the  course 
of  time.  If,  on  the  contrary,  much  meat  besides  proportionally 
little  fat  is  given,  then  the  deposit  of  proteid  with  increased 
metabolism  is  smaller  day  by  day,  and  nitrogenous  equilibrium  is 
attained  in  a  few  days.  In  spite  of  the  daily,  somewhat  larger 
deposit,  the  total  flesh  deposit  is  not  considerable  in  these  cases. 
The  following  experiment  of  Vott  may  serve  as  example: 

Table  IX. 


Number  of  Days 

of  Expeiiinenta- 

tioii. 

Fo 
Meat,  grriis. 

od. 
Fat,  grms. 

Total 

Deposit  of 

Flesli. 

Daily 

Deposit  of 

Klesh. 

Nitrogenous 
Equilibrium 

32 

7 

500 
1800 

250 
250 

1792 
854 

56 
122 

not  attained 
attained 

The  greatest  absolute  deposition  of  flesh  in  the  body  was 
obtained  in  these  cases  with  only  500  grms.  flesh  and  250  grms.  fat, 
and  even  after  32  days  the  nitrogenous  equilibrium  had  not 
occurred.  On  feeding  with  1800  grms.  meat  and  250  grms.  fat  the 
nitrogenous  equilibrium  occurred  after  7  days;  and  though  the 
deposition  of  flesh  per  day  was  greater,  still  the  absolute  deposit  was 
not  one  half  as  great  as  in  the  former  case.  Inasmuch  as  the 
quantity  of  proteids  does  not  decrease  below  a  certain  amount,  it 
seems  that  the  most  abundant  and  most  lasting  deposition  of  flesh 
is  obtained  with  a  food  which  does  not  contain  too  much  proteids  in 
proportion  to  the  fat.  The  same  is  also  true  of  a  diet  consisting  of 
proteids  and  carbohydrates. 

The  experiments  of  Krug  '  on  himself,  under  the  direction  of 
V.  NooRDEN,  give  us  information  as  to  the  practicability  of  flesh 
deposition  in  man.     "With  abundant  food  (2590  cal.  =  44  cal.  per 


'  Cited  from  v.  Noorden's  Lehrbncb  der  Path,  des  StofEwechsels.   Berlin, 
1893.  S.  120. 


DEPOSITION  OF  FLESH.  641 

\\\o)  Krug  was  close  to  nitrogenous  equilibrium  for  six  days.  He 
then  increased  tiie  nutritive  supply  to  4300  cal.  =  71  cal.  per  kilo 
for  15  days  by  the  addition  of  fat  and  carbohydrate,  and  in  this  time 
309  grms.  proteid,  corresponding  to  1455  grms.  flesh,  was  spared. 
Of  the  excess  of  administered  calories  in  this  case  only  5^  was  used 
for  flesh  deposit  and  95^  for  fat  deposit.  As  the  large,  excessive 
quantity  of  food  was  only  transitorily  and  reluctantly  eaten,  this 
experiment,  as  v.  Noorden  has  correctly  emphasized,  has  placed 
the  difiiculty  of  flesh  deposition  in  another  light.  We  must  admit 
with  V.  NooRDEN  that  it  is  impossible  to  produce  a  permanent  flesh 
deposit  in  man  by  overfeeding,  and  that  it  is  not  possible  to  make 
a  person  muscle-strong  by  excessive  feeding. 

Flesh  deposition  is,  according  to  v.  Noorden,  a  function  of  the 
specific  development  energy  of  the  cells  and  the  cell-work  to  a  much 
higher  extent  than  the  excess  of  food.  Therefore  we  observe, 
according  to  v.  Noorden,  abundant  flesh  deposition  (1)  in  each 
growing  body;  (2)  in  those  no  longer  growing  but  whose  body 
is  accustomed  to  increased  work  (hypertrophy  of  the  muscles  by 
work) ;  (3)  whenever,  by  previous  insufficient  food  or  by  disease, 
the  flesh  condition  of  the  body  has  been  diminished  and  is  com- 
pensated by  abundant  food.  The  deposition  of  flesh  is  in  these 
cases  an  expression  of  the  regenerative  energy  of  the  cells. 

The  experiences  of  cattle-raisers  show  that  in  food-animals  a 
flesh  deposit  does  not  occur,  or  at  least  is  only  inconsiderable,  on 
over-feeding.  The  individuality  and  the  race  of  the  animal  is  of 
imjiortance  for  flesh  deposition. 

As  a  direct  formation  of  fat  is  denied,  and  if  it  does  occur  it  is 
only  very  insignificant,  the  most  essential  requisite  for  a  fat  deposi- 
tion must  be  an  overfeeding  with  non-nitrogenous  nutritive  bodies. 
The  extent  of  fat  deposition  is  determined  by  the  excess  of  admin- 
istered calories  over  those  used.  If  a  large  part  of  the  caloric  de- 
mand is  covered  by  j^roteid,  then  a  greater  part  of  the  simultane- 
ously given  non-nitrogenous  food-stuffs  is  spared,  i.e.,  used  for  fat 
deposition.  But  as  proteid  and  fat  are  expensive  nutritive  bodies  as 
compared  with  carbohydrates,  the  supply  of  greater  quantities  of  car- 
bohydrates is  important  for  fat  deposition.  The  body  decomposes 
less  substance  at  rest  than  during  activity.  Bodily  rest,  besides  a 
proper  combination  of  the  three  chief  groups  of  organic  foods,  is> 
therefore  also  an  essential  requisite  for  an  abundant  fat  deposit. 

The  fat  formed   in  fat  deposition  originates,  as  stated  above. 


642  -  METABOLISM. 

entirely  from  the  carbohydrates  according  to  PFLiJGER's  doctrine. 
In  this  fat-formation,  as  suggested  by  Harriot  '  and  Pfluger,^  a 
splitting  off  of  carbon  dioxide  takes  place  from  the  carbohydrates. 
This  carbon  dioxide,  which  in  excessive  feeding  with  carbohydrates 
is  expired,  has,  according  to  Pfluger,  a  double  origin.  It  is  in 
part  split  off  from  the  carbohydrates  in  the  formation  of  fat,  and  it 
originates  in  part  from  the  combustion  of  carbohydrates.  This 
behavior  explains  the  circumstance  that  after  partaking  large  quan- 
tities of  carbohydrates  the  respiratory  quotient,  as  first  shown  by 
Hanriot  and  then  also  by  M.  Bleibtreu,^  was  raised  under  cir- 
cumstances to  1.2-1.3. 

Action  of  certain  other  Bodies  on  Metabolism.  Water.  If  a 
quantity  in  excess  of  that  which  is  necessary  is  introduced  into  the 
organism,  the  excess  is  quickly  and  principally  eliminated  with  the 
urine.  This  increased  elimination  of  urine  causes  in  fasting 
animals  (Voit,*  Forster^),  but  not  to  any  appreciable  degree  in 
animals  taking  food  (SEEGEiq",''  Salkowski  and  Munk,^  Mater/ 
Cfbelir"),  an  increased  elimination  of  nrea.  The  reason  for  this 
increased  elimination  is  sought  for  in  the  fact  that  the  abundant 
drinking  of  water  causes  a  complete  washing  out  of  the  urea  from 
the  tissues.  Another  view,  which  is  defended  by  Voit,  is  that 
because  of  the  more  active  current  of  fluids  after  taking  large  quan- 
tities of  water  an  increased  metabolism  of  proteids  takes  place. 
Voit  considers  this  explanation  the  correct  one,  although  he  does 
not  deny  that  by  the  abundant  administration  of  water  a  more  com- 
plete washing  out  of  the  urea  from  the  tissues  takes  place. 

In  regard  to  the  action  of  water  on  the  formation  of  fat  and  its 
metabolism,  the  view  that  free  drinking  of  water  is  favorable  for 
the  deposition  of  fat  seems  to  be  generally  admitted,  while  taking 
only  very  little  water  acts  against  its  formation. 

Salts.  The  excretion  of  urine,  even  when  no  great  quantities 
of  water  are  taken,  is  increased  by  common  salt,  and  the  elimination 

'  Compt.  rend.,  Tomie  114. 

2  Pfliiger's  Arch.,  Bd.  52,  S.  45. 

^  Ihid.,  Bd.  56. 

-*  Untersunli.  iiber  den  Einfluss  des  Kochsalzes,  etc.     Mtinclien,  1860. 

^  Cited  from  Voit  in  Hermann's  Handbuch,  Bd.  6,  S.  153. 

*  Wien.  Sitzungsber. ,  Bd.  63. 

'  Vircbow's  Arcb.,  Bd.  71. 

8  Zeitscbr   f.  klin.  Med.,  Bd.  2. 

9  Zeitscbr.  f.  Biologie,  Ed.  28. 


ACTION  OF  SALTS  AND  ALCOHOL.  643 

of  urea  is  also  increased  at  the  same  time.  The  same  two  possibili- 
ties may  be  considered  for  this  last  as  in  the  action  of  water  on  the 
excretion  of  urea.  The  experiments  continued  for  a  long  time  by 
VoiT,  in  which  the  absolute  increase  of  the  elimination  of  urea  was 
considerable  (106  grms,  in  49  days),  render  the  conclusion  probable 
that  common  salt  somewhat  increases  the  metabolism  of  the  pro- 
teids.  DuBELiR  has  obtained  contrary  results  which  he  considers 
was  due  to  giving  the  animal  large  quantities  of  common  salt.  It  is 
possible  that  the  decomposition  activity  of  the  cells  may  be  reduced 
on  giving  large  quantities  of  salt.  Certain  other  salts,  such  as  potas- 
sium chloride,  sodium  sulphate,  sodium  phosphate,  sodium  acetate, 
saltpetre,  and  ammonium  chloride,  also  seem  to  act  like  common 
salt.  Sodium  borate  and  the  sodium  salts  of  salicylic  and  benzoic 
acids  also  seem  to  huva  an  increased  action  on  the  metabolism  of 
proteids. 

Alcohol.  The  question  as  to  how  far  the  alcohol  absorbed  in  the 
intestinal  canal  is  burnt  in  the  body,  or  whether  it  leaves  the  body 
unchanged  by  various  channels,  has  been  the  subject  of  much  dis- 
cussion. To  all  appearances  the  greatest  part  of  the  alcohol  is 
burnt.  According  to  Bodlander,'  1.18^  of  the  alcohol  taken  is 
eliminated  with  the  urine,  0.14^  by  the  evaporation  ftoni  the  skin, 
and  l.Gfo  with  the  expired  air.  The  remainder,  or  about  97^,  is 
burnt  in  the  body.  As  the  alcohol  is  in  greatest  part  burnt  in  the 
body  and  has  a  high  calorific  value  (1  grm.  =  7  cal.),  then  the 
question  arises  whether  it  acts  sparingly  on  other  bodies,  and 
whether  it  is  to  be  considered  as  a  nutritive  body.  The  investiga- 
tions made  to  decide  this  question  have  led  to  no  decisive  result. 
In  the  experiments  on  the  elimination  of  nitrogen  in  human  beings 
sometimes  a  diminished  (Hammond,  E.  Smith,  Obernier),  some- 
times an  unchanged  (Parkes  and  Wollowicz'),  while  in  other 
cases  an  increased  (Forster  and  Eomeyn  ^)  elimination  of  nitroo-en 
was  observed  after  the  administration  of  small  amounts  of  alcohol. 
In  the  recent  experiments  of  Stammreich  and  v.  JSTooRDEiir  * 
alcohol  could  only  replace  the  isodynamic  quantity  of  non-nitrog- 
enous food-stuffs,   without   an   essential   influence  on  the  proteid 

1  Pfliiger's  Arch..  Bd.  32. 

2  In  regard  to  the  older  investigations  see  Volt  in  Hermann's  Handbuch 
Bd.  6,  S.  170. 

3  Maly's  Jahresber.,  Bd.  17,  S.  400. 

*  V.  Nooiden,  Alkobol  als  Sparmittel.     Berlin,  klin.  Wochenscbr.,  1891. 


644:  METABOLISM. 

condition  of  the  body,  in  a  food  richer  in  proteid  than  ordinarily^ 
MiUEA  '  could  not  find  any  sparing  action  on  proteids  by  alcohol  in 
his  experiments,  and  according  to  him  alcohol  cannot  replace  the 
sparing  actioa  of  carbohydrate  on  proteid.  Fokker  ^  and  I.  MuifK  '* 
after  the  administration  of  small  quantities  of  alcohol  to  dogs  found 
a  diminished,  and  after  large  quantities  an  increased,  metabolism 
of  proteids,  Chittendejst,  Norris,  and  E.  Smith  '  make  the 
statement,  based  on  their  experiments  with  1.9,  2.3,  and  2.7  c.  c. 
alcohol  per  kilo  of  dog  per  diem,  that  alcohol  acts  like  a  non- 
nitrogenous  nutritive  body  in  regard  to  its  sparing  action  on 
proteids. 

Many  observations  have  been  made  on  animals  in  regard  to  the 
extent  of  exchange  of  gas  after  taking  alcohol.  The  results  in  these 
cases  are  somewhat  different,  depending  upon  the  size  of  dose  and 
the  kind  of  animal.  In  an  investigation  on  the  human  body  Zuntz 
and  Berdez,*  and  also  Geppert,°  observed  no  essential  change  in 
the  respiratory  exchange  of  gas  after  small,  non-intoxicating  doses 
of  alcohol.  As  alcohol  is  in  greatest  part  burnt  up  in  the  bod)^  and 
the  exchange  of  gas  is  nevertheless  not  essentially  raised,  it  seems 
as  if  the  alcohol  diminishes  the  combustion  of  other  bodies  and 
thereby  has  a  sparing  value.  Corresponding  to  this,  as  is  well 
known,  a  deposition  of  fat  may  take  place  in  the  body  under  the 
influence  of  alcohol.  The  nutritive  value  of  alcohol  may  be  of 
essential  importance  only  in  certain  cases,  as  large  quantities  of 
alcohol  taken  at  once  or  the  continued  use  of  smaller  quantities  has 
injurious  action  on  the  organism.  Alcohol  may  therefore  be  con- 
sidered as  a  nutritive  body  only  in  exceptional  cases,  and  it  other- 
wise must  be  considered  as  an  article  of  luxury. 

Coffee  and  tea  have  no  positively  proved  action  on  the  exchange 
of  material,  and  their  importance  lies  chiefly  in  their  action  upon 
the  nervous  system.  It  is  impossible  to  enter  into  the  action  of 
various  therapeutic  agents  upon  metabolism. 

'  Zeitsclir.  f.  klin.  Med.,  Bd.  20.  Cited  from  Maly's  Jabresber.,  Bd.  23, 
S.  461. 

*  Cited  from  Voit  in  Hermann's  Handbucb,  Bd.  6,  S.  170. 
3  Du  Bois-Reymond's  Arcb.,  1879,  S.  163. 

*  Journal  of  Pbysiology,  Vol.  12 

s  See  Maly's  Jabresber.,  Bd.  7,  S.  343. 
»  Arch.  f.  Patb.  u.  Pbarm.,  Bd.  22. 


DEPENDENCE  ON   OTHER   CONDITIONS.  (54; 


V.  The  Dependence  of  Metabolism  on  Other 
Conditions. 

The  previously  mentioned  so-called  abstinence  value,  i.e.,  the 
extent  of  metabolism  with  absolute  bodily  rest  and  inactivity  of  the 
intestinal  tract,  serves  best  as  a  starting-point  for  the  study  of 
metabolism  under  various  external  circumstances.  The  metabolism 
going  on  under  these  conditions  leads  in  the  first  place  to  the  pro- 
duction of  heat,  and  it  is  only  to  a  subordinate  degree  dependent 
upon  the  work  of  the  circulatory  and  respiratory  apparatus  and  the 
activity  of  the  glands.  According  to  a  calcalation  by  Zuntz,' 
only  10-20^  of  the  total  calories  of  the  abstinence  value  belongs  to 
the  circnlation  and  respiration  work. 

The  extent  of  the  abstinence  value  depends  in  the  first  place 
upon  the  heat  production  necessary  to  cover  the  loss  of  heat,  and 
this  heat  production  is  in  turn  dependent  upon  the  relationship 
between  the  weight  of  body  and  the  surface  of  the  body. 

Weight  of  Body  and  Age.  The  greater  the  mass  of  the  body  the 
greater  the  absolute  consumption  of  material;  while  on  the  con- 
trary, other  things  being  equal,  a  small  Individ nal  of  the  same  species 
of  animals  metabolizes  absolutely  less,  but  relatively  more  as  com- 
pared with  the  unit  of  the  weight  of  the  body.  It  must  be  remarked 
that  we  mean  flesh  weight  when  we  say  body  weight.  The  extent 
of  the  metabolism  is  dependent  upon  the  quantity  of  living  cells, 
and  a  very  fat  individual  therefore  decomposes  less  substance  per  kilo 
than  a  lean  person  of  the  same  weight  of  body.  In  women,  who 
generally  have  less  bodily  weight  and  a  greater  quantity  of  fat  thaa 
men,  the  metabolism  in  general  is  smaller,  and  the  latter  is  ordi- 
narily about  \  of  that  of  men.  Otherwise  sex  does  not  seem  to 
have  any  special  influence  on  the  exchange  of  material. 

The  essential  reason  why  small  animals  decompose  relatively  more 
substance,  i.e.,  as  calculated  on  the  kilos  of  the  body,  than  large  ones 
is  that  the  smaller  animals  have  greater  bodily  surface  in  proportion 
to  their  mass.  On  this  account  the  loss  of  heat  is  greater,  which 
causes  increased  heat  production,  i.e.,  a  more  active  metabolism. 
This  is  also  the  reason  why  young  individuals  of  the  same  kind 
show  a  relatively  greater  decomposition  than  older  ones.     Eubis^er,  * 

•  Cited  from  v.  Noorden's  Lebrbuch,  etc.,  S.  97. 
'  Zeitschr.  f.  Biologic,  Bdd.  21  u.  19. 


646 


METABOLISM. 


whom  we  have  to  thank  especially  for  our  knowledge  ia  regard  to 
the  bearing  of  the  relative  surfacial  development  on  the  extent  of 
metabolism,  has  given  us  the  following  table  on  this  point  with 
respect  to  man: 


Table  X. 


Calories  in 

24  Hours 

Calories  per 

after  Sub- 

Calories  in 

Surface  in 

Square 

tractins:  the 

24  Hours 

Square 

Centimetre 

Heat,  of  Com- 

per Kilo. 

Centimetres. 

of 

bustion  of 

Surface. 

the  Faeces. 

Children  weigMng  4.03  kilos.. 

368 

91.3 

3013 

1221 

11.8    "      .. 

966 

81.5 

7191 

1343 

16.4   "     .. 

1213 

739 

7681 

1579 

23.7   "     .. 

1411 

59.5 

10156 

1389 

30.9   "     .. 

1784 

57.7 

12122 

1472 

40.4   "     .. 

2106 

52.1 

144^)1 

1452 

Man                 ' 

67.0   "     .. 

2843 

42.4 

20305 

1399 

If  we  exclade  the  smallest,  actively  growing  children,  in  whose 
case  special  conditions  govern,  we  find  that  the  heat  production 
for  the  unit  of  surface  of  body  varies  only  a  few  per  cent  from  the 
average  of  1447  cal.  We  see  how  the  relative  extent  of  surface 
decreases  with  an  increase  in  the  mass  of  the  body.  Correspondent 
with  this  the  metabolism  per  kilo  of  body  weight  also  decreases, 
and  it  is  smallest  in  adults. 

A  similar  result  was  obtained  by  Richet'  in  his  investigations 
on  the  elimination  of  carbon  dioxide  in  dogs  of  various  sizes,  as 
elucidated  in  the  following  table : 

Tablk  XI. 


Averasre  Weierht 
of  Body  iu  Kilos. 

COj  eliminated  in 

Grammes  per  Kilo 

in  1  Hour. 

Surface  of 

Body  in 

Square  Centimetres. 

COj  eliminated  in 

Grammes  per 

lODO  Square 

Centimetres. 

24  0 

1.026 

9296 

2  65 

13.5 

1.210 

6272 

2.60 

11.5 

1.380 

5656 

281 

90 

1.506 

4816 

2.81 

6.5 

1.624 

3920 

2.69 

5.0 

1.688 

3282 

2  57 

31 

1.984 

2341 

2.71 

2.3 

2.265 

1926 

2.70 

'  Arch,  de  Physiol.  (5),  Bd.  2. 


WEIGHT  OF  BODY  AND  AGE.  t;47 

The  raising  of  the  metabolism  which  is  necessary  to  cover  the 
loss  of  heat  because  of  the  relatively  larger  surface  of  body  in  small 
animals  is  due,  according  to  Eichet,  to  the  influence  of  the 
nervous  system,  which  may  be  reduced  by  chloral  hydrate.  In  the 
last  case  the  quantity  of  carbon  dioxide  produced  per  kilo  in  dogs 
of  various  sizes  is  nearly  the  same. 

The  question  whether  the  active  metabolism  in  young  animals 
depends  upon  a  more  active  decomposition  in  the  cells  than  in  older 
animals  is  still  undecided. 

As  the  total  calories  exchanged  per  kilo  of  body  weight  in  young 
animals  is  greater  than  in  older  ones,  this  difference  must  be  seen 
in  measuring  as  well  the  exchange  of  gas  as  the  elimination  of 
nitrogen.  This  is  true,  and  we  give  here  Camerer's  '  figures 
on  the  elimination  of  urea  in  children. 

Table  XII. 

Age.  Weight  of  Body  in  Kilos.  Urea  in  grms. 

Per  Day.  Per  Kilo» 

U  years 10.80  12.10  1.35 

3  "     13.30  11.10  0.90 

5  "     16.20  12.37  0.76 

7  "    ..* 18.80  14.05  0.75 

9  "    25.10  17.27  0,69 

12i  '      32  60  17.79  0.54 

15  "    35.70  17.78  0.50 

In  adults  weighing  about  70  kilos  about  30-35  grms.  urea  per 
day  are  eliminated,  or  0.5  grm.  per  kilo.  At  about  15  years  of  age 
the  destruction  of  proteids  per  kilo  is  about  the  same  as  in  adults. 
The  relatively  greater  metabolism  of  proteids  in  young  individuals 
is  explained  partly  by  the  fact  that  the  metabolism  of  material  in 
general  is  more  active  in  young  animals,  and  partly  by  the  fact  that 
young  animals  are  as  a  rule  poorer  in  fat  than  those  full  grown. 

As  the  metabolism  may  be  kept  at  its  lowest  point  by  absolute 
rest  of  body  and  inactivity  of  the  intestinal  tract,  it  is  manifest  that 
work  and  the  taking  up  of  food  have  an  important  bearing  on  the 
extent  of  metabolism. 

Rest  and  Work.  During  work  a  greater  quantity  of  potential 
energy  is  converted  into  living  force,  i.e.,  the  metabolism  is 
increased  more  or  less  on  account  of  work. 

As  explained  in  a  previous  chapter  (XI)  work,  according  to  the 
generally  accepted  view,  has   no  material  influence  on  the  elimi- 

'  Zeitschr.  f.  Biologie,  Bdd.  16  n.  20. 


648  METABOLISM. 

Tiation  of  nitrogen.  It  is  nevertheless  true  that  several  investigators 
in  certain  cases  have  observed  an  increased  elimination  of  nitrogen; 
but  these  observations  have  been  explained  in  other  ways. 

For  instance,  work  may,  when  it  is  connected  with  violent  move- 
ments of  the  body,  easily  cause  dyspnoea,  and  this  last,  as  Fran- 
KEL '  has  shown,  since  diminution  of  the  oxygen  supply  increases 
the  proteid  metabolism,  may  cause  an  increase  in  the  elimina- 
tion of  nitrogen.  In  other  series  of  experiments  the  quantity  of 
carbohydrates  and  fats  in  the  food  was  not  sufficient;  the  supply 
of  fat  in  the  body  was  decreased  thereby,  and  the  destruction  of 
proteids  was  correspondingly  increased.  "Work  may  also  increase 
the  appetite,  and  an  increase  in  the  elimination  of  nitrogen  may  be 
caused  by  the  greater  quantity  of  proteids  taken.  According  to 
the  generally  accepted  views  muscular  activity  has  hardly  any  influ- 
ence on  the  metabolism  of  proteids. 

On  the  contrary,  woik  has  a  very  considerable  influence  on  the 
elimination  of  carbon  dioxide  and  the  consumption  of  oxygen.  This 
action,  which  was  first  observed  by  Lavoisiee,  has  recently  been 
confirmed  by  many  investigators.  Pettestkofer  and  Voit  "^  have 
made  investigations  on  a  full-grown  man  as  to  the  metabolism  of 
ihe  nitrogenous  as  well  as  of  the  non-nitrogenous  bodies  during  rest 
•and  work,  partly  while  fasting  and  partly  on  a  mixed  diet.  The 
experiments  were  made  on  a  full-grown  man  weighing  70  kilos. 
The  results  are  contained  in  the  following  table: 

Table  XIII. 

Consumption  of 


Proteids.  Fat.    Carbohydrates.    CO,  eliminated.      O  consumed. 

T?oct;^„       jl^est       79        209  ...  716  761 

'*^"°^--- ]  Work     75         380  ...  1187  1071 

Mixed  diet  I  ^«^*      1^^  ^2  ^^2  913  831 

'^"^®"  ^'®^  ]  Work  137         173  353  1309  980 

In  these  cases  work  did  not  seem  to  have  any  influence  on  the 
destruction  of  proteids,  while  the  gas  exchange  was  considerably 
increased. 

ZuNTZ  and  his  pupils  Lehmann  '  and  Katzenstein  *  have 
made  very  important  investigations  on  the  extent  of  the  exchange 

1  Virchow's  Arch.,  Bdd.  67  u.  71. 
»  Zeitschr.  f.  Biologie,  Bd.  2. 
»  Maly's  Jahresber.,  Bd.  19,  S.  413. 
*Pfluger's  Arch.,  Bd.  49. 


REST  AND    WORK.  tUl^ 

of  gas  as  a  measure  of  metabolism  during  work  and  caused  by  work, 
using  Zuntz-Geppert's  method  (see  page  G04).  These  investiga- 
tions not  only  show  the  important  influence  of  muscular  work  on  the 
decomposition  of  material,  but  they  also  show  in  a  very  instructive 
way  the  relationship  between  the  extent  of  metabolism  of  material 
and  useful  work  of  various  kinds.  We  can  only  refer  to  these  im- 
portant investigations,  which  are  of  special  physiological  interest. 

The  action  of  muscular  work  on  the  gas  exchange  does  not 
alone  appear  with  hard  work.  From  the  researches  of  Speck,'  who 
has  also  made  very  meritorious  studies  on  the  exchange  of  gas 
in  man  under  various  conditions,  we  learn  that  even  very  small, 
apparently  quite  unessential  movements  may  increase  the  produc- 
tion of  carbon  dioxide  to  such  an  extent  that  by  not  observing  these, 
as  in  numerous  older  experiments,  very  considerable  errors  may 
creep  in. 

The  quantity  of  carbon  dioxide  eliminated  during  a  working 
period  is  uniformly  greater  than  the  quantity  of  oxygen  taken  up  at 
the  same  time,  and  hence  a  raising  of  the  respiratory  quotient  was 
formerly  usually  considered  as  caused  by  work.  This  rise  does  not 
seem  to  be  based  upon  the  kind  of  chemical  processes  going  on 
during  work,  as  we  have  a  series  of  experiments  made  by  Zuntz, 
Lehmanx,  and  Katzexstein"  in  which  tlie  respiratory  quotient 
remained  almost  wholly  unchanged  in  spite  of  work.  According  to 
Loewy'  the  combustion  processes  in  the  animal  body  go  on  in  the 
same  way  in  work  as  in  rest,  and  a  raising  of  the  respiratory  quotient 
(irrespective  of  the  transient  change  in  the  respiratory  mechanism) 
takes  place  only  with  insufficient  supply  of  oxygen  to  the  muscles,  as 
in  continuous  fatiguing  work  or  short  excessive  muscular  activity, 
also  with  local  lack  of  oxygen  caused  by  excessive  work  of  certain 
groups  of  muscles.  This  varying  condition  of  the  respiratory 
quotient  has  been  explained  by  Katzexstein"  '  by  the  statement 
that  during  work  two  kinds  of  chemical  processes  act  side  by  side. 
The  one  depends  upon  the  work  which  is  connected  with  the  pro- 
duction of  carbon  dioxide  also  in  the  absence  of  free  oxygen,  while 
the  other  brings  about  the  regeneration  which  takes  place  by  the  tak- 
ing up  of  oxygen.  When  these  two  chief  kinds  of  chemical  processes 
make  the  same  progress  the  respiratory  quotient  remains  unchanged 

■  Speck,  Physiologic  des  menschlichen  Atbmens.     Leipzig,  1893. 
*  Pflilger's  Arch.,  Bd.  49. 
'  JW(f.,  Bd.  49. 


650  METABOLISM. 

during  work;  if  by  hard  work  the  decomposition  is  increased  as 
compared  with  the  regeneration,  then  a  raising  of  the  respiratory 
quotient  takes  place. 

In  sleep  metabolism  decreases  as  compared  with  that  during 
waking,  and  the  most  essential  reason  for  this  is  the  muscular 
inactivity  during  sleep.  The  investigations  of  RuBifER  '  on  a  dog, 
and  of  LoEWT  ^  on  human  beings,  teach  us  that  if  the  muscular  work 
is  eliminated  the  metabolism  during  waking  is  not  greater  than  in 
sleep. 

The  action  of  light  also  stands  in  close  connection  to  the  question 
of  the  action  of  muscular  work.  It  seems  positively  proven  that 
metabolism  is  increased  under  the  influence  of  light.  Most  investi- 
gators, such  as  Speck:, ^  Loeb,*  and  Ewald,^  consider  that  this 
increase  is  due  to  the  movements  caused  by  the  light  or  an  increased 
muscle  tonus.  Fubini  and  Benedicenti  *  assume  that  the  in- 
crease in  metabolism  due  to  light  is  independent  of  the  movements. 
They  base  this  assumption  on  experiments  made  on  hibernating 
animals. 

Mental  activity  does  not  seem  to  have  any  influence  on  meta- 
bolism. 

Action  of  the  External  Temperature.  In  cold-blooded  animals 
the  production  of  carbon  dioxide  increases  and  decreases  with  the 
rise  and  fall  of  the  surrounding  temperature.  In  warm-blooded 
animals  this  condition  is  the  reverse.  By  the  investigations  of 
LuDWiG  and  Sanders-Ezn,  Pfluger  and  his  pupils,  and  Duke 
Charles  Theodore  of  Bavaria  and  others,'  it  has  been  demon- 
strated that  in  warm-blooded  animals  the  change  in  the  external 
temperature  has  different  results  according  as  the  animal's  own 
heat  remains  the  same  or  changes.  If  the  temperature  of  the 
animal  sinks,  the  elimination  of  carbon  dioxide  decreases;  if  the  tem- 
perature rises,  the  elimination  of  00^  increases.  If,  on  the  contrary, 
the  temperature  of  the  body  remains  unchanged,  then  the  elimina- 
tion of  carbon  dioxide  increases  with  a  lower  and  decreases  with 

'  Ludwig- Festschrift,  1887. 
»  Berlin,  kiln.  Woclienscbr.,  1891,  S.  434. 
»  L.  c. 

*  Pflilger's  Arch.,  Bd.  42. 
'  Journal  of  Physiol.,  Vol.  13. 
6  See  Maly's  Jahresber.,  Bd.  22,  S.  395. 

'  The  i)ertinent  literature  may  be  found  cited  by  Volt  in  Hermann's  Hand- 
buch,  Bd.  6,  and  also  by  Speck,  1.  c. 


INFLUENCE  OF  EXTERNAL   TEMPERATURE.  651 

a  higher  external  temperature.  This  fact  may  be  explained, 
according  to  Pfluger  and  Zuntz,  by  the  statement  that  the  low 
temperature,  by  exciting  a  reflex  action  in  the  sensitive  nerves  of 
the  skin,  causes  an  increased  metabolism  in  the  muscles  with  an 
increased  production  of  heat,  affecting  the  temperature  of  the  body, 
while  with  a  higher  external  temperature  the  reverse  takes  place. 
The  experiments  made  on  animals  are  somewhat  uncertain  for 
several  reasons,  but  the  determinations  of  the  oxygen  absorption,  as 
well  as  the  elimination  of  CO,,  made  by  Speck  '  and  Loewy  '  on 
human  beings,  have  shown  that  cold  does  not  produce  any  essential 
increase  in  the  metabolism  of  man.  The  irritation  caused  by  cold 
may  reflexly  cause  a  forced  respiration  with  an  action  on  the 
gas  exchange,  and  weak  reflex  muscular  movements,  such  as 
shivering,  trembling,  etc.,  may  cause  an  insignificant  increase  in  the 
elimination  of  carbon  dioxide;  in  complete  muscular  inactivity  cold 
seems  to  cause  no  increased  absorption  of  oxygen  or  increased 
metabolism.  According  to  Loewy  the  most  essential  thing  in  the 
regulation  of  heat  under  the  influence  of  cold  is,  not  an  increased 
production  of  heat,  but  rather  a  diminished  loss  of  heat  by  contrac- 
tion of  the  skin  and  its  vessels. 

Metabolism  is  increased  by  the  partahing  of  food,  and  Zuntz' 
has  calculated  that  in  man  the  consumption  of  oxygen  is  raised  on 
an  average  15^  for  about  6  hours  after  taking  a  moderately  hearty 
meal.  This  increase  in  the  metabolism  is  caused,  according  to  the 
generally  accepted  view  of  Speck,  probably  only  by  the  increased 
work  of  the  digestive  apparatus  on  the  partaking  of  food.  FiCK* 
claims  that  the  increased  metabolism  is  due  to  the  oxidation  of  the 
circulating,  combustible  material  (proteid).  This  view,  as  shown 
by  Magnus-Levy,"  is  not  correct;  but  still  Levy  inclines  to  the 
vjew  that  besides  the  digestion  work  the  proteids  may  possibly  also 
have  a  specific  exciting  action  on  metabolism. 

'  L.  c. 

*  Pflilger's  Arch.,  Bd.  46. 

^  Zuntz   and   Levy,  Beitrag   zur   Kenntniss   der   Verdauliclikeit,  etc.,  des 
Erodes.     Pflilger's  Arcb.,  Bd.  49. 

*  Sitzungsber.  d.  Wurzb.  pliys.-med.  Gesellscli.,  1890. 

*  Pflilger's  Arch.,  Bd.  55,  contains  the  pertinent  literature. 


652  METABOLISM. 


VI.  The  IVeed  of  Food  by  Man  under  Various 
Conditions. 

Various  attempts  have  been  made  to  determine  the  daily- 
quantity  of  organic  food  needed  by  man.  Certain  investigators 
have  calculated,  from  the  total  consumption  of  food  by  a  large 
number  of  similarly  fed  individaals,  soldiers,  sailors,  laborers,  etc., 
the  average  quantity  of  food  required  per  head.  Others  have  cal- 
culated the  daily  demand  of  food  from  the  quantity  of  carbon  and 
nitrogen  in  the  excreta.  Others  again  have  calculated  the  quantity 
of  nutritive  material  in  a  diet  by  which  an  equilibrium  was  main- 
tained in  the  individual  for  one  or  several  days  between  the  con- 
sumption and  elimination  of  carbon  and  nitrogen.  Lastly,  others 
still  have  quantitatively  determined  during  a  period  of  several  days 
the  organic  nutritive  substances  consumed  daily  by  persons  of  vari- 
ous occupations  who  chose  their  own  food,  by  which  they  were  well 
nourished  and  rendered  f  ally  capable  of  labor. 

Among  these  methods  a  few  are  not  quite  free  from  reproach, 
and  others  have  not  as  yet  been  tried  on  a  sufficiently  large  scale. 
Nevertheless  the  experiments  collected  thus  far  serve,  partly 
because  of  their  number  and  partly  because  of  the  methods,  to 
correct  and  control  one  another,  and  also  serve  as  a  good  starting- 
point  in  determining  the  diet  of  various  classes  and  similar 
questions. 

If  the  quantity  of  nutritive  substance  taken  daily  be  converted 
into  calories  produced  daring  physiological  combastion,  we  then 
obtain  some  idea  of  the  sum  of  the  chemical  potential  energy  which 
under  varying  conditions  is  introduced  into  the  body.  It  must 
not  be  forgotten  that  the  food  is  never  completely  absorbed,  and 
that  undigested  or  unabsorbed  residues  are  always  expelled  from 
the  body  with  the  faeces.  The  gross  results  of  calories  calculated 
from  the  food  taken  must  therefore,  according  to  Kubkee,'  be 
diminished  at  least  8^. 

The  following  summary  contains  certain  examples  of  the 
quantity  of  food  which  is  consumed  by  individuals  of  various  classes 
tinder  different  conditions.  In  the  last  column  we  also  find  the 
quantity  of  living  force  which  corresponds  to  the  quantity  of  food 
in  question,  calculated  as  calories,  with  the  above-stated  correction. 

1  Zeitschr.  f.  Biologie,  Bd.  21,  S.  379. 


NEED   OF  FOOD   BY  MAN.  053 

The  calories  are  therefore  net  results,   while  the   figures  for  the 
nutritive  bodies  are  gross  results. 

Table    XIV. 
Proteids.       Fat.   jjy^J".|^°gg  Calories.  Authority. 

Soldier  during  peace 119  40  529  2784  Playfair." 

"       1  gilt  service 117  35  447  2424  Hildesheim. 

"      infield 146  46  504  2852 

Laborer 130  40  550  2903  Moleschott. 

"      at  rest  137  72  352  2458  Pettenkofer  &  VoiT. 

Cabinet-maker  (40  years).  131  68  494  2835  Fokstek.» 

Young  physician 127  89  302  2602 

134  102  292  2476 

Laborer  133  95  422  2902 

English  smith 176  71  666  3780  Playfair. 

puuilist 288  88  93  2189 

Bavarian  wood-chopper..  135  208  876  5589  Liebig. 

Laborer  in  Silesia 80  16  552  2518  Meinert.* 

Seamstress  in  London...  54  29  292  1688  Playfair. 

Swedish   laborer 134  79  485  3019  Hultgren  &  Lander- 

Japanese  student 83  14  622  2779  Eijkman.*          [gren.* 

"          shopman 55  6  394  1744  Tawara.^ 

It  is  evident  that  persons  of  essentially  different  weight  of  body 
who  live  under  unequal  external  conditions  must  need  essentially 
different  food.  It  is  also  to  be  expected  (and  this  is  confirmed  by 
the  table)  that  not  only  the  absolute  quantity  of  food  consumed  by 
various  persons,  but  also  the  relative  proportion  of  the  various 
organic  nutritive  substances,  shows  considerable  variation.  Results 
for  the  daily  need  of  human  beings  in  general  cannot  be  given. 
For  certain  classes  of  human  beings,  such  as  soldiers,  laborers,  etc., 
results  may  be  given  which  are  valuable  for  the  calculation  of  the 
daily  rations. 

Based  on  extensive  investigations  and  a  very  wide  experience, 
VoiT  has  proposed  the  following  average  quantities  for  the  daily 
diet  of  adults: 

Proteids.  Fat.  Carbohydrates.    Calories. 

For  men 118  grms.         56  grms.         500  grms.         2810 

But  it  should  be  remarked  that  these  statements  relate  to  a  man 
weighing  70  to  75  kilos  and  who  was  engaged  daily  for  ten  hours 
in  not  too  fatiguing  labor. 

'  In  rejrard  to  the  older  researches  cited  in  this  table  we  refer  the  reader 
to  Voit  iu  Hermann's  H^ndbuch,  Bd.  6,  S.  519. 

-  Ibid,  and  Zeitschr.    f.  Biologie,  Bd.  9. 

3  Armee-  und  Volksernahriing.     Berlin,  1880, 

^  Investigations  on  the  food  of  Swedish  laborers  with  free  selected  diet. 
Stockholm,  1891. 

'  Cited  from  Kelner  and  Mori  in  Zeitschr.  f.  Biologie,  Bd.  25. 


654  METABOLISM. 

The  quantity  of  food  required  by  a  woman  engaged  in  moderate 
work  is  about  |  that  of  a  laboring  man,  and  we  may  consider  the 
following  as  a  daily  diet  with  moderate  work: 

Proteids.  Fat.  Carbohydrates.  Calories. 

For  women 94  grms.         45  grms.         400  grms,         2340 

The  proportion  of  fat  to  carbohydrates  is  here  as  1  :  8-9.  Such 
a  proportion  occurs  often  in  the  food  of  the  poorer  classes,  while 
the  ratio  in  the  food  of  wealthier  persons  is  1  :  3-4.  The  maximum 
quantity  of  carbohydrates  in  the  food  must,  according  to  Voit,  not 
be  above  500  grms. ;  and  as  the  carbohydrates  besides  constitute  the 
chief  part  of  the  often  very  bulky  vegetable  foods,  it  has  been  sug- 
gested and  is  desirable  on  this  and  other  grounds  to  increase  the 
quantity  of  fat  at  the  expense  of  the  carbohydrates  in  such  rations. 
But  because  of  the  high  price  of  fat  such  a  modification  cannot 
always  be  made. 

In  examining  the  above  numbers  for  the  daily  rations  it  must 
not  be  forgotten  that  the  figures  for  the  various  nutritive  bodies  are 
gross  results.  They  consequently  represent  the  quantity  of  the 
nutritive  bodies  which  must  be  taken  in,  and  not  those  which  are 
really  absorbed.  The  figures  for  the  calories  are,  on  the  contrary, 
net  results. 

The  various  foods  are,  as  is  well  known,  not  equally  digested  and 
absorbed,  and  in  general  the  vegetable  foods  are  less  completely 
used  up  than  animal  foods.  This  is  especially  true  of  the  proteids. 
"When,  therefore,  Voit,  as  above  stated,  calculates  the  daily 
quantity  of  proteids  needed  by  a  laborer  as  118  grm?.,  he  starts  with 
the  supposition  that  the  diet  is  a  mixed  animal  and  vegetable  one, 
and  also  that  of  the  above  118  grms.  about  105  grms.  are  absorbed. 
The  results  obtained  by  Pflugee  and  his  pupils  Bleibtkeu  '  and 
Bohlaistd"  for  the  extent  of  the  metabolism  of  proteids  in  man 
with  an  optional  and  sufficient  diet  correspond  well  with  the  above 
figures,  when  the  unequal  weight  of  body  of  the  various  persons 
experimented  upon  is  sufficiently  considered. 

As  a  rule,  the  more  exclusively  a  vegetable  food  is  employed, 
the  smaller  is  the  quantity  of  proteids  in  the  same.  The  strictly 
vegetable  diet  of  certain  people,  as  of  the  Japanese  and  that 
of  the  so-called  vegetarians,  is  therefore  a  proof  that,  if  the 
quantity  of  food  be  sufficient,  a  person  may  exist  on  considerably 

1  Pfluger's  Arch.,  Bd.  36. 
»  Ibid.,  Bd.  38. 


NEED   OF  FOOD  BY  MAN.  655 

smaller  qnantities  of  proteids  than  VoiT  suggests.  It  follows  from 
the  investigations  of  IIirschfeld,  Kumagawa.,  and  Klemperer 
(see  page  638)  that  a  nearly  complete  or  indeed  a  complete  nitrog- 
enous equilibrium  may  be  attained  by  the  sufficient  administration 
of  non-nitrogenous  nutritive  bodies  with  relatively  very  small 
quantities  of  proteids. 

If  we  bear  in  mind  that  the  food  of  people  of  different  countries 
varies  greatly,  and  that  the  individual  also  takes  essentially  different 
nourishment  according  to  the  external  conditions  of  living  and  the 
influence  of  climate,  it  is  not  remarkable  that  a  person  accustomed 
to  a  mixed  diet  cannot  exist  for  a  long  time  on  a  strictly  vegetable 
diet  deficient  in  proteids,  even  though  not  especially  difficult  to 
digest.  No  one  doubts  the  ability  of  man  to  adapt  himself  to  a 
heterogeneously  composed  diet  when  this  is  not  too  difficult  of 
digestion  and  is  sufficient;  but  this  ability  does  not  seem  sufficient 
reason  for  essentially  altering  the  figures  suggested  by  VoiT. 
Although  man  may  be  satisfied  under  certain  circumstances  with  a 
lower  quantity  of  proteid  than  that  calculated  by  VoiT,  still  it  does 
not  follow  that  such  a  diet  is  also  the  most  serviceable.  Voit's  fig- 
ures are  only  given  for  certain  cases  or  certain  categories  of  human 
beings.  It  is  apparent  that  other  figures  must  be  taken  for  other 
cases,  and  it  is  evident  that  the  daily  ration  given  by  Voit  as  neces- 
sary for  a  laborer  must  be  altered  slightly  for  other  countries  because 
of  the  existing  conditions  in  middle  Europe,  where  Voit  made  his 
investigations.  For  example,  Hultgren"  and  Landergren  have 
shown  in  very  careful  investigations  that  the  laborer  in  Sweden  with 
moderate  work  and  an  average  body  weight  of  70.3  kilos,  with 
optional  diet,  partakes  134  grms.  proteid,  79  grms.  fat,  and  522 
grms.  carbohydrates.  The  quantity  of  proteid  partaken  of  is  here 
greater  than  is  necessary  according  to  Voit. 

If  we  compare  the  figures  of  Table  XIV  with  the  average  figures 
proposed  by  Voit  for  the  daily  diet  of  a  laborer,  it  would  seem  at 
the  first  glance  as  if  the  consumed  food  in  certain  cases  was  con- 
siderably in  excess  of  the  need,  while  in  other  cases,  as  for  instance 
for  the  seamstress  in  London,  it  was  entirely  insufficient.  A  posi- 
tive conclusion  cannot,  therefore,  be  drawn  if  we  do  not  know  the 
weight  of  the  body,  as  well  as  the  labor  performed  by  the  person, 
and  also  the  conditions  of  living.  It  is  certainly  true  that  the 
amount  of  nutriment  required  by  the  body  is  not  directly  propor- 
tional to  the  bodily  weight,  for  a  small  body  consumes  relatively 


656  METABOLISM. 

more  snbstaiice  than  a  larger  one,  and  varying  quantities  of  fat  may 
also  cause  a  difference;  but  a  large  body,  which  must  maintain  a 
greater  quantity,  consumes  an  absolutely  greater  quantity  of  sub- 
stance than  a  small  one,  and  in  estimating  the  nutritive  need  one 
must  also  always  consider  the  weight  of  the  body.  According  to 
VoiT,  the  diet  for  a  laborer  with  70  kilos  bodily  weight  requires  40 
calories  for  each  kilo. 

As  several  times  stated  above,  the  demands  of  the  body  for 
nourishment  vary  with  its  varying  conditions.  Among  these  con- 
ditions two  are  especially  important,  namely,  labor  and  rest. 

Iq  a  previous  chapter,  in  which  muscular  labor  was  spoken  of, 
it  was  seen  that  the  generally  accepted  vieAv  is  that  non-nitrogenous 
food  is  the  most  essential,  if  not  the  exclusive,  source  of  muscular 
force.  As  a  natural  sequence  it  is  to  be  expected  that  in  activity 
the  non-nitrogenous  foods  before  all  must  be  increased  in  the  daily 
rations. 

Still  this  does  not  seem  to  hold  true  in  daily  experience.  It  is 
a  well-known  fact  that  hard-working  individuals — men  and  animals 
— require  a  greater  quantity  of  proteids  in  the  food  than  less  active 
ones.  This  contradiction  is,  however,  only  apparent,  and  it 
depends,  as  Voit  has  shown,  upon  the  fact  that  individuals  used  to 
violent  work  are  more  muscular.  For  this  reason  a  person  perform- 
ing severe  muscular  labor  requires  food  containing  a  larger  propor- 
tion of  proteids  than  an  individual  whose  occupation  demands  less 
violent  exertion.  Another  question  is,  how  should  the  relative  and 
absolute  quantity  of  food  be  changed  if  increased  exertion  be 
demanded  of  one  and  the  same  individual? 

An  answer  based  upon  experience  may  be  found  in  statistics 
concerning  the  maintenance  of  soldiers  in  peace  and  in  war.  Many 
such  statements  are  obtainable.  In  a  critical  examination  of  the 
sune  it  is  found  that  in  war  rations  the  quantity  of  n  on- nitrogenous 
bodies  as  compared  to  the  proteids  is  only  increased  in  exceptional 
cases,  while  usually  the  reverse  is  the  case.  Even  in  these  cases  the 
actual  proportion  does  not  correspond  with  the  theoretical  demand, 
upon  which,  however,  too  great  stress  must  not  be  placed,  since  in 
the  case  of  soldiers  in  the  field  many  other  circumstances  are  to  be 
considered,  such  as  the  volume  and  weight  of  the  food,  etc.,  etc., 
which  cannot  here  be  more  closely  discussed.  The  following  table 
shows  the  average  results  of  soldiers'  rations  in  war  and  peace  from 


NEED   OF  FOOD  BY  MAN.  '  657 

the  data  given  for  various  countries/     These  average  results  also 
include  the  figures  for  Sweden. 

Table  XV. 
A.    Peace  Ration.  B.    War  Ration. 

Proteids.    Fat.  Carb.  Proteids.   Fat.  Garb. 

Minimum 108        23  504  126        38  484 

Maximum 165        97  731  197        95  688 

Mean 130        40  551  146         59  557 

Sweden  (proposed)....   179       102  591  202       137  565 

xf  we  do  not  consider  the  very  abundant  rations  proposed  for 
the  soldier  in  Sweden,  and  if  we  only  adhere  to  the  above  mean 
figures,  we  obtain  the  following  results  for  the  daily  rations : 

Proteids.         Fat.  Carb.  Calories. 

In  peace.   130  40  551  2900 

Inwar 146  59  557  8250 

If  we  calculate  the  fat  in  its  equivalent  quantity  of  starch,  then 
the  relation  of  the  proteids  to  the  non-nitrogenous  foods  is: 

In  peace 1:4.97 

Inwar 1:4.79 

The  proportion  is  nearly  the  same  in  both  cases;  the  slight 
difference  which  occurs  shows  a  trifling  relative  increase  in  the 
proteids  in  the  war  ration.  On  the  contrary,  as  is  especially 
iapparent  from  the  total  of  the  calories,  the  total  quantity  of  nutri- 
tive bodies  is  greater  in  the  war  than  in  the  peace  ration. 

As  more  work  requires  an  increase  in  the  absolute  quantity  of 
food,  so  the  quantity  of  food  must  be  diminished  when  little  work 
is  performed.  The  question  as  to  how  far  this  can  be  done  is  of 
importance  in  regard  to  the  diet  in  prisons  and  poorhouses.  We 
give  below  the  following  as  example  of  such  diets: 

Table  XVI. 

Proteids.   Fat.  Carb.  Calories. 

Prisoner  (not  working) 87        22  305        1667      Schuster.* 

....  85        30  300        1709      Voit. 

Man  in  poorhouse 92        45  332         1985      Forster.^ 

Woman  in     "        80        49  266         1725 

The  figures  given  by  Voit  are,  according  to  him,  the  lowest 

'  Germany,   Austria,   Switzerland,    France,   Italy,   Russia,  and  the  United 
States, 

'  See  Voit,  Untersuchung  der  Kost.     Miinclien,  1877.     S.  142. 
^  Ibid.,  S.18Q. 


658  METABOLISM. 

figures  for  a  noa- working-  prisoner.     He  considers  the  following  as 
the  lowest  diet  for  old  non-working  people: 

Proteids. "     Fat.  Carb.         Calories. 

Men 90  40  350  2300 

Women 80  35  300  1733 

In  calculating  the  daily  diet  it  is  in  most  cases  sufi&cient  to 
ascertain  how  much  of  the  various  nutritive  substances  must  be  daily 
administered  to  the  body  to  keep  it  in  the  proper  condition  to  per- 
form the  work  required  of  it.  In  other  cases  it  may  be  a  question  of 
improving  the  nutritive  condition  of  the  body  by  properly  selected 
food ;  but  we  also  have  cases  in  which  we  desire  to  diminish  the 
mass  or  weight  of  the  body  by  an  insufficient  nutrition.  This  is 
especially  the  case  in  obesity,  and  all  the  dietaries  proposed  for  this 
purpose  are  chiefly  starvation  cures. 

The  oldest  and  most  generally  known  diet  cure  for  corpulency 
is  that  of  Harvey,'  which  is  ordinarily  called  the  Bantii^g  method. 
The  principle  of  this  cure  consists  in  increasing,  as  far  as  possible, 
the  consumption  of  the  accumulated  fat  of  the  body  by  as  limited 
a  supply  of  fat  and  carbohydrates  as  possible  and  a  simultaneous 
increased  supply  of  proteids.  A  second  cure,  called  Ebstein"'s  ' 
cure,  is  based  on  the  assumption  (not  correct)  that  the  fat  of  the 
food  is  not  accumulated  in  a  body  rich  in  fat,  but  is  completely 
burnt.  In  this  cure  large  quantities  of  fat  are  therefore  allowed  in 
the  food,  while  the  quantity  of  carbohydrates  is  diminished  very 
materially.  The  third  cure,  called  Oertel's^  cure,  is  based  on  the 
correct  view  that  a  certain  quantity  of  carbohydrates  has  no  greater 
influence  in  the  accumulation  of  fat  than  the  isodynamic  quantities 
of  fat.  In  this  cure,  therefore,  carbohydrates  as  well  as  fat  are 
allowed,  provided  the  total  quantity  of  the  same  is  not  so  great  as 
to  hinder  the  decrease  in  the  fatty  condition.  A  greatly  diminished 
supply  of  water  is  also  one  of  the  features  of  Oertel's  cure, 
especially  in  certain  cases.  The  average  quantity  of  the  various 
nutritive  substances  supplied  to  the  body  in  these  three  cures  is  as 
follows,  and  we  give  also  for  comparison  in  the  same  table  Voit's 
diet  necessary  for  a  laborer : 

Proteids.     Fat.       Carb.     Calories. 

Harvey-Banting's  cure 171  8  75  1066 

Ebstein's  cure 102  85  47  1391 

Oertel's       "    156  23  73  1124 

"    (max.) 170  44  114  1557 

Laborer,  according  to  VoiT 118  56  500  3810 

'  Banting,  Letter  on  Corpulence.    London,  1864. 

*  Ebstein,  Die  Fettliebigkeit  und  ihre  Behandlung.    1883. 

2  Oertel,  Handbuch  der  allg.  Therapie  der  Kreislaufstorungen.     1884. 


STARVATION  CURES.  659 

If  the  fat  in  all  cases  is  recalcnlated  in  starch,  then  the  propor- 
tion of  the  proteids  to  the  carbohydrates  is: 

Harvey-Banting's  cure  100  :    54 

Ebstein's  cure 100  :  246 

Oertel's      "    100:    80 

"    (max.) 100:129 

Laborer 100  :  540 

In  all  these  cures  for  corpulence  the  quantity  of  non-nitrogenous 
hodies  is  diminished  as  compared  with  the  proteids;  but  chiefly  the 
total  quantity  of  food,  as  is  shown  by  the  number  of  calories,  is 
considerably  diminished. 

Haryet-Baxting's  cure  differs  from  the  others  in  a  relatively 
very  much  greater  quantity  of  proteids,  while  the  total  number  of 
calories  in  it  is  the  smallest.  On  this  account  this  cure  acts  very 
quickly ;  but  it  is  therefore  also  more  dangerous  and  more  difficult 
to  accomplish.  In  this  regard  Ebsteix's  and  Oertel's  cures 
(especially  Oertel's),  having  a  greater  variation  in  the  selection  of 
food,  are  better.  As  the  adipose  tissue  has  a  proteid-sparing  action, 
we  have  to  consider  in  using  these  cures,  especially  Banting's, 
that  the  destruction  of  proteids  in  the  body  is  not  increased  with 
the  decrease  in  the  adipose  tissue,  and  one  must  therefore  carefully 
watch  the  elimination  of  nitrogen  by  the  urine.  All  diet  cures  for 
obesity  are  moreover,  as  above  stated,  starvation  cures;  and  if  the 
daily  quantity  of  food  required  by  an  adult  man,  represented  as 
calories,  is  in  round  numbers  2500  calories  (according  to  the  average 
figures  found  by  Forster  in  the  case  of  a  physician),  then  one 
immediately  sees  what  a  considerable  part  of  its  own  mass  the  body 
must  daily  give  up  in  the  above  cures.  This  reminds  us  of  the 
great  care  necessary  in  employing  these  cures;  but  each  special  case 
should  be  conducted  with  regard  to  the  individuality,  the  weight 
of  the  body,  the  elimination  of  nitrogen  in  the  urine,  etc.,  etc.,  and 
always  under  strong  control  and  only  by  physicians,  never  by  a 
layman.  A  closer  discussion  of  the  many  conditions  which  must 
be  considered  in  these  cases  does  not  enter  into  the  plan  and  scope 
of  this  work. 


660 


FOOD   TABLES. 


TABLE  I.— FOODS. > 


1.  Animal  Foods. 


1000  Parts  contain 


CLhH 


Relationship  of 


}8 


a.  Flesh  without  Bonks 

Fat  beef'' 

Beef  (average  f at  ^) 

Beef2 

Corned  beef  (average  fat) 

Veal 

Horse,  salted  and  smoked. . . , 

Smoked  ham 

Pork,  salted  and  smoked  ■* 

Flesh  from  hare 

"        "     chicken , 

"        "     partridge , 

•'        "     wild  duck 

6.  Flesh  with  Bones. 

Fat  beef  5 

Beef,  average  f at^ 

Beef,  slightly  corned 

Beef,  thoroughly  corned 

Mutton,  very  fat 

"        average  fat 

Pork,  fresh,  fat 

Pork,  corned,  fat 

Smoked  ham 

c.  Fishes. 

River  eel,  fresh,  entire 

Salmon,         "  "  

Anchovy,      "  "  

Flounder,      "  "  .,,... 

River  perch,"  "  

Torsk,  "  " 


183 
196 
190 
218 
190 
318 
255 
100 
233 
195 
253 
246 


156 
167 
175 
190 
135 
160 
100 
120 
200 


89 
121 
128 
145 
100 


166 

98 

120 

115 

80 

65 

365 

660 

11 

93 

14 

31 


141 
83 
93 
100 
332 
160 
460 
540 
300 


220 

6 

39 

14 

2 

1 


11  640 

18  688 

18l  672 

1171  550 

13  717^ 

125  492 

100  280 


130 

744 
701 
14{  719 
12  711 


9 

15 

85 

100 


544 
585 
480 
430 
437 

10:  520 

5  365 
60:  200 
70  340 


150 

150 

16 

180 
88 

150 
70 
80 
90 


6  352  333 

10  469,  333 


489  333 

580  250 

440  450 

8i  455  450 


100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 


100 
100 
100 
100 
100 
100 
100 
100 
100 


100 
100 
100 
100 
100 
100 


90 

50 

63 

53 

42 

20 

143 

660 

5 

48 

6 

18 


90 
49 
53 
53 

246 
100 
460 
450 
150 


246 

56 

31 

9 

2 

1 


0 
0 
0 
0 
0 
-0 
0 
0 
0 
0 
0 
0 


'  The  results  in  the  following  tables  are  chiefly  compiled  from  the  summary  of  Alm^n 
and  of  KoNiG.  As  "  waste  "  we  here  designate  that  part  of  the  foods  which  is  lost  ii?  the 
preparation  of  the  food  or  that  which  is  not  used  by  the  body ;  for  instance,  the  bones, 
skin,  egs-shell,  and  the  cellulose  in  the  vegetable  foods. 

"  Meat  such  as  is  orrlinnrily  sold  in  the  markets  in  Sweden. 

»  Beef  such  as  is  delivered  by  larg-e  purveyors  to  public  institutions  in  Sweden. 

*  Pork,  chiefly  from  the  breast  and  belly,  such  as  occurs  in  the  rations  of  Swedish 
goldiers. 


ANIMAL  FOODS. 


t)t)l 


TABLE  l.—YOOli^.— (Continued.) 


Animal  Foods. 


Pike,  fresh,  entire 

Herring,  salted,  entire 

Anchovy,     "  "    

Salmon  (side),  salted 

Kabeljau  (salted  haddock) 

Codfish  (dried  ling) 

"       (dried  torsk) 

Pish-meal  from  variety  of  Gadus 

d.  Inner  Organs  (Fresh). 

Brain 

Beef-liver 

Beef-heart 

Heart  and  lungs  of  mutton.  . . . 

Veal-kidney 

Ox-tongue  (fresh) 

Blood    from     various    animals 
(average  results). . .   

e.  Other  Animal  Foods. 

Kind    of    pork-sausage    (Mett 

wurst) 

Same  for  frying 

Butter 

Lard 

Meat  extract 

Cow's  milk  (full) 

"    (skimmed) 

Buttermilk 

Cream 

Cheese  (fat) 

(poor) 

Whey  cheese  (poor)  

Hen's  egg,  entire 

•'     without  shell 

Yolk  of  egg 

White"    " 


1000  Parts  contain 


Sg 


82 
140 
116 
200 
246 
532 
665 
736 


116 
196 

184 
163 
221 
150 

182 


190 

220 

7 

3 

304 

35 

35 

41 

37 

230 

334 

89 

106 

122 

160 

103 


1 

140 

43 

108 

4 

5 

10 


103 
56 
92 

106 
38 

170 


150 
160 
850 
990 

35 

7 

9 

257 

270 

66 

70 

93 

107 

307 

7 


11 


50 

50 

38 

35 

40 

50 

456 

4 

5 


100 
107 
132 
178 
106 
59 
87 


50 
55 
15 

175 

7 

7 

7 

6 

60 

50 

56 

8 

10 

13 


461 

280 

334 

460 

472 

25 

116 

170 


770 
720 
714 
721 

728 
670 

807 


610 
565 
119 
7 
21 
873 
901 
905 
665 
400 
500 
329 
6o4 
756 
520 
875 


Relationship  of 


450  100 
340  100 
400:  100 
lOOl  100 
lOOi  100 
100  100 
150  100 
100 


100 
100 
100 
100 
100 
100 


135 


100 


100 
100 
100 
100 

100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 


1 

100 
37 
54 
1 
1 
1 
1 


28 
50 
65 
17 
113 


79 

73 

12100 

33000 

100 
20 
22 

695 

117 
19 
79 
88 
88 

192 


662 


FOOD  TABLES. 


TABLE  l.—FOOT>^.— {Continued.) 


2.  Vegetable  Foods. 


Wheat  (grains) 

Wheat-flour  (fine) 

"         (veiy  fine) 

Wheat-bran 

Wheat-bread  (fresh).. 

Macaroni 

Rye  (grains) 

Rye-flour 

Rye-bread  (dry) 

"       "      (fresh,  coarse) 

"       "      (fresh,  fine) 

Barley  (grains) 

Scotch  barley 

Oat  (grains) 

Oat  (peeled) 

Corn 

Rice  (peeled  for  boiling) 

French  beans 

Peas  (yellow  or  green) 

Flour  from  peas , 

Potatoes 

Turnips 

Carrot  (yellow) 

Cauliflower 

Cabbage 

Beans 

Spinach 

Lettuce 

Cucumbers 

Radishes 

Edible  mushrooms  (average).. . 
Same  dried  in  the  air  (average) 

Apples  and  pears 

Various  berries  (average) 

Almonds 

Cocoa. 


1000  Parts  contain 


133 

110 

92 

150 

88 

90 

115 

115 

114 

77 

80 

111 

110 

117 

140 

101 

70 

232 

220 

270 

20 

14 

10 

25 

19 

27 

31 

14 

10 

12 

33 

219 

4 

5 

243 

140 


17 

10 

11 

39 

10 

3 

17 

15 

30 

10 

14 

21 

10 

60 

60 

58 

7 

31 

15 

15 

3 

2 

3 


1 
5 
3 
1 
1 
4 
25 


537 

480 


676 

740 

768 

439 

550 

768 

688 

730 

725 

480 

514 

654 

720 

563 

660 

656 

770 

537 

530 

520 

200 

74 

90 

50 

49 

66 

33 

22 

23 

38 

60 

412 

130 

90 

72 

180 


140 
120 
120 
130 
330 
131 
140 
110 
110 
400 
370 
140 
146 
130 
100 
140 
146 
137 
150 
125 
760 
893 
873 
904 
900 
888 
908 
944 
956 
934 
877 
160 
832 
849 
54 
55 


36 

2 

6 

192 

5 

22 
20 
16 
17 
11 
48 

7 

100 

20 

28 

5 

37 
60 
45 

8 
10 
15 

9 

18 
12 


18 
133 
31 
50 
66 
95 


Relationship  of 


1  .-2         : 3 


100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 
100 


14 

11 

12 
26 

11 

8 

15 

13 

18 

14 

18 

19 

9 

51 

43 

57 

10 

9 

7 

6 

10 

14 

30 

16 

11 

4 

16 

31 

10 

8 

13 

13 


233 
343 


54» 
654 
835 
29a 
635 
85a 
600 
626 
634 
633 
634 
589 
654 
481 
471 
663 

1100 
331 
240 
193 

1030 
529 
900 
200 
258 
244 
106 
157 
230 
317 
188 

18a 

3250 

1800 

30 

139 


MALT  AND  ALCOHOLIC  LIQUORS. 


663 


TABLE  II.— MALT  LIQUORS. 


1000  Parts  by  Weight 
contain 


Porter 

Beer  (Swedish) 

"     (Swedish  export). . 

Draught-beer 

Lager  beer 

Bock-beer 

Weiss-beer 

Swedish  "  Svagdricka". 


u 

C  (U 

o 

u 

■a 

u 

d 

a 

% 
^ 

OS  o 

«5 

o 
o 

< 

1 

2 

."2 
'3 

u 

5 

871 
887 

2 

54 

28 

76 

7 
15 

13 

3 

— 

65 

885 

32 

— 

7 

73 

— 

— 

911 

2 

35 

55 

8 

10 

31 

2 

2 

903 

2 

40 

58 

4 

7 

47 

1.5 

3 

881 

2 

47 

72 

6 

13 

— 

1.7 

— 

916 
945 

3 

25 
22 

59 

5 

7 

— 

— 

4 

— 

23 

—       4 

5 
3 

2 
3 
3 
2 


TABLE  III.-AVINE  AND   OTHER  ALCOHOLIC   LIQUORS. 


1000  Parts  by  "Weight 
contain 


Bordeaux  wine , 

White  wiue  (Rheiugau) 

Champagne 

Rhine  wine  (sparkling) 

Tokay 

Sherry 

Port- wine , 

Madeira 

Marsala 

Swedish  punch 

Brandy 

French  cognac 

Liqueurs 


.a 

6-- 

6 

V 

^l 

% 

•gss 

'u 

si 

m 

^ 

o 

^ 

3 
02 

•C  CO  1- 

■BSS 

3 

< 

883 

94 

23 

6 

5.9 

2.0 

863 

115 

33 

4 

5.0 

3.0 

776 

90 

134 

115 

6.0 

1.0 

1.0 

801 

94 

105 

87 

6.0 

1  0 

3.0 

808 

130 

73 

51 

7.0 

9.0 

3.0 

795 

170 

35 

15 

5.0 

6.0 

5.0 

774 

164 

62 

40 

4.0 

2.0 

3.0 

791 

156 

53 

33 

5.0 

3.0 

3.0 

790 

164 

46 

35 

5.0 

4.0 

4.0 

479 

363 

460 

550 

443-590 

332 
260-475 

fltt 


60-70 


664  INDEX  TO  SPECTRUM  PLATE. 


SPECTEUM    PLATE. 

1.  Absorption  spectrum  of  a  solution  of  oxyhmmoglohin. 

2.  Absorption  spectrum  of  a  solution  of  hmmoglobin,  obtained  by  the  action  of 

an  ammoniacal  ferro-tartrate  solution  ou  an  oxy haemoglobin  solution. 

3.  Absorption  spectrum  of  a  faintly- alkaline  solution  of  methoRmoglobin. 

4.  Absorption  spectrum  of  a  solution  of  hcBmatin  in  ether  containing  oxalic 

acid. 

5.  Absorption  spectrum  of  an  alkaline  solution  of  Jmmaiin. 

6.  Absorption  spectrum  of  an  alkaline  solution  of  Jicsmochromogen,  obtained  by 

the  action   of    an    ammoniacal   ferro-tartrate   solution  on  an    alkaline- 
hsematin  solution. 

7.  Absorption  spectrum  of  an  acid  solution  of  urobilin. 

8.  Absorption  spectrum  of  an  alkaline  solution  of  urobilin  after  the  addition  of 

a  zinc-chloride  solution. 

9.  Absorption  spectrum  of  a  solution  of  lutein  (ethereal  extract  of  the  egg-yolk). 


B     C  D 

Is       s       7       e      d       to     It 


E    I)  F  G 

le     je    /jr    /b     /o    so    p/     ps     23      ?*    |?5 


/U       /.?       /g      /j7 

iiiiliiiliiiiliiiiliiiiliiiilmiliii 


iiilrtiliiiiliiilliiiililiiliiiiliililiiiiliii 


liiliiiiliiiiliiiiliiiiliiiilllllllllllhiilNillillilliiiiiiiiliiiiliiMlMiiliililiiiiliiiilllilllMiliiiilniiliililmilii 


I 


.T    ;   «  /? 


%. 


n  nr 


j: 


Tm|Tii|iiii|iif||iiii|Mii|iiii|iiii|iiii[iiijiii|iiii|iiii|iiii|iiii|iiii|im|iiii|iiTi|mi]iii^^^^^^ 


/J 


i'        5  \6       1  B       &        JO       t/       iS      I3\        M      JS     16        II      J8      19      "20      2/        2?       13      1'r     '2S 

BCD  E    h  F  G 


INDEX. 


Absorption,    326—341 

,   importance     of    cells    in, 

330,  340,  341 
,    action      of      putrefactive 
processes   jn    the    intes- 
tine on,  320 
Absorption  ratio,  147 
Acetic  acid  in  intestinal  contents,  314 
in  gastric  juice,  264 

contents,       264, 
283,  288 
,  passage  of,  into  the  urine, 
505,  523 
Acetone,  558 

in  blood,  176 
in  urine,  556,  557 
Acetonuria,  556,  557 
Acetyl-amido-benzoic  acid,  528 
Acetylene,    compound   with   haemoglo- 
bin, 140 
Acholia,  pigmentary,  242 
Achromatin,  96 
Achroo-dextrin,  78,  256 
Acid  albuminates,  16 

,  properties,  32,  33 
,  formation  in  peptic 
digestion,  271,  272 
Acid  amides,  behavior  in  the  animal 

body,  523 
Acid  rigor,  375 

Acids,    organic,   behavior   in   the   ani- 
mal body,  449,  505,  517,  518,  523 
Acidity  of  urine,  448 — 451 

of  the  gastric  contents,  284 
of  the  muscles,  360,  376 


Aerite,  67 

Acrolein,  82 

Acrolein  test,  82,  85 

Acroses,  67 

Acrylic  acid,  action  on  the  elimination 

of  uric  acid,  473 
Acrylic  acid  diureid.     See  Uric  acid. 
Actiniochrom,  578 
Adamkiewicz's  reactiion,  27 
Adelomorphic   cells,  261 
Adenin,  102 

,   properties,   reaction,   and   oc- 
currence, 107 
,   urine,   484 
Adenylic  acid,  99 

Adhesion,  importance  in  blood  coagu- 
lation, 155 
Adipocere,  355 
^^gagropila,   325 
Aerotonometer,  597,  600 
Alanin,  57 
Albumins,  18 

,  general  properties,  30. 
See   also   the   various   albu- 
mins. 
Albumin,  detection  in  urine,  531 

,  quantitative  estimation,  536 
See  Proteids. 
Albuminates,  18 

,  properties  and  reactions, 

32,  33 
,  ferruginous  albuminate 
in  the  spleen.  201 
Albuminoids,  18,  49 

in  cartilage,  347 
665 


Q66 


INDEX. 


Albumoids,  18,  49 

in  the  crystalline  lens,  401 
Albuminous  bodies.   See  Proteid  bodies. 
Albuminous  glands,  251 
Albumoses,  18 

,  general  properties,  33 — 42 
,  formation  in  putrefaction 

of  proteid,  314 
,  formation  in  pepsin  diges- 
tion, 271 
,  formation    in    trypsin    di- 
gestion, 302 
,  nutritive  value,  636 
,  absorption,  327 
,  transformation     of,     into 

proteid,  329 
,   occurrence     of^      in     the 

blood,  328 
,  occurrence    in    the    urine, 
535 
Alcapton  and  alc^ptonuria,  493,  498, 

499 
Alcohol.     See   Ethyl  alcohol. 
Alcoholic  fermentation,  9,  68 

in       intestine, 

313 
in  milk,  429 
Aldepalmitic  acid,  424 
Aldoses,  60,  63 
Aleuron  grains,  411 
Alexines,  16,  179 
Alkali  albuminate,  18 

,  properties  and  re- 
actions, 32,  33 
,        .  ,   occurrence   in   the 

yolk  of  the  egg, 
412 
occurrence    in    the 

brain,  390 
occurrence  i  n 

smooth  muscles, 
389 
,  Lieberkiihn's,  32 
Alkali  carbonate,  physiological  impor- 
tance, 628 
,  action  on  the  secre- 
tion     of      gastric 
juice,  263 


Alkali  carbonate,  occurrence.     See  the 

various  tissues  and  fluids. 
Alkali  phosphates  in  urine,  448,  477, 
513 
,  occurrence.    See  the 
various  tissues 
Alkali  urates,  447,  478 

in  calculi,  569 
in  sediments,  447,  566 
Alkaline  earths  in  urine,   519 
in  bones,  349 
,  insufficient  supply  of, 
351,  629 
Alakaline  fermentation  of  urine,  565 
Alkaloids,  action  on  the  muscles,  375 
,  passage  of,  into  the  urine, 

530 
,  retention  by  the  liver,  206 
Alimentary  glycosuria,  220,  332 
Alimentary  oxaluria,  482 
Alizarin  in  the  urine,  530 
,  feeding  with,  351 
Alizarin  blue,  behavior  in  the  tissues,  5 
Allantoic  fluid,  483 

Allantoin,   properties   and   occurrence, 
483 
,  in  transudations,   191,   194, 

419 
,   formation    from   uric    acid, 
472 
Alloxan,  472,  478 

Allyl   alcohol,   relationship   to   forma- 
tion of  glycogen,  214 
Almen-Bottger's  sugar  test,  69,  546 
Alnien's  guaiacum  blood  test,  539 
Amanitin,  93 
Ambergris,  326 
Ambrain,  326 

Amido-acids,  relation  to  formation  of 
uric  acid,  475 
,  relation  to  formation  of 

urea,  455,   523 
,  formation    in    putrefac- 
tion, 23,  314 
from  protein  substances,, 
20—22,  50,  54,  56,  57, 
302,  314 
in  trypsin  digestion,  302 


INDEX. 


66r 


Amido-acetic  acid.     See  Glycocoll. 
Amido-benzoie    acid,    behavior   in   the 

animal  body,  528 
Amido-caproic  acid.     See  Leucin. 
Amido-cinnamic  acid,  526 
Amido-ethylen-lactic  acid.     See   Serin. 
Amido-oxyethyl-sulphonic    acid.      See 

Taurin. 
Amido-phenyl-acetic  acid,  behavior  in 

body,  527 
Amido-phenyl-propionic     acid,    forma- 
tion in  the  putrefaction  of  proteids. 
23,  486 
Amido-phenyl-propionic   acid,  behavior 

in  organism,  526,  527 
Amido-succinic    acid.      See    Aspaitij 

acid. 
Amidulin,  76.  256 
Ammonia,  estimation  of,  518 

formation  in  proteid  putre- 
faction, 314 
from  protein  substances,  20, 

21,  302,  314 
in  trypsin  digestion,  302 
,  occurrence  in  blood,  176 
,   occurrence    in    the    urine. 
448,    454,    458,    459,    517, 
518 
Ammonia    elimination    after    admin' s- 

tration  of  mineral  acids,  517,  518 
Ammonia    elimination    in    diseases    of 

the  liver,  454,  459 
Ammonia    elimination    after    extirpa- 
tion of  the  liver,   and  atrophy   ex- 
periments, 459,  475 
Ammonium  chloride,  relation  to  forma- 
tion    of     urea, 
517 
,  action  on  metab- 
olism. 643 
Ammonium  salts,  relation  to  formation 
of  glycogen,  214 
,  relation  to  uric-acid 

formation,  475 
,  relation     to     urea 
formation,  455, 457 
Ammonium-magnesium    phosphate    in 
urinary  calculi,  569,  570 


Ammonium-magnesium    phosphate    in 
urinary  sediments,  568 

Ammonium   urate  in  urinary  calculi, 
569 

Ammonium    urate    in    urinary    sedi- 
ments, 566 

Amniotic  fluid,  419 

Amphicreatinin,  369 

Amphopeptone,  35 

Amyl  nitrite,  poisoning  with,  177 

Amylodextrin,  76 

Amyloid,  57 

,  vegetable,  79 

Amyloid  degeneration,  bile  in,  242 

Amyloid     degeneration,     chondroitin- 
sulphuric  acid  in  the  liver,  344 

Amylolytic  enzymes,  13,  255,  297 

Amylopsin,  297 

Amylum.     See   Starch. 

Anaemia,  pernicious,  174 

Anhydride  theory  of  glycogen  forma- 
tion, 215 

Anilin,  behavior  in  the  animal  body, 
526 

Anisotropous  substance,  361 

Antedonin,  578 

Anthrax  protein,  19 

Anthrax  spores,  behavior  with  gastric 
juice,  282 

Antialbumose,  35 

Antimony,     passage     of,     into     milk, 
443 
,     action   on   elimination   of 
nitrogen,  453 

Antipeptone,  35 

in  meat  extract.  308 

Antipyrin,    relation    to    formation    of 
glycogen,  214 
,  action  on  urine,  530 

Apatite,  349 

Approximate  estimation  of  proteid  in 
urine,  536 

'Aqueous  humor,  195 

Arabinoses,  61,  65,  80 

,  relation    to    formation    of 
glycogen,  213 

Arabit,  61 

Arachidic  acid  in  butter,  424 


668 


INDEX. 


Arachnoidal  fluid,  190 

Arbutin,   relation  to  glycogen   forma- 
tion, 214 
,  behavior    in    animal    body, 
493 
Arginin,  50 

Aromatic  compounds,  behavior  in  ani- 
mal body,  525 — 531 
Arsenic,  passage  of,  into  milk,  443 
in  perspiration,  581 
,  action  on  the  elimination  of 
nitrogen,  453 
Arsenious  acid,  action  on  pepsin  diges- 
tion, 270 
Arsenuretted       hydrogen,       poisoning 

with,  244—247,  538 
Arterin,  130 
Ascitic  fluids,  193 

Asparagin,  relation  to  proteid  synthe- 
sis, 23 
,  relation    to    formation    of 

glycogen,  214 
,  nutritive  value,  637 
Asparaginic  acid.      See  Aspartie  acid. 
Asparagus,    odoriferous   bodies    of,    in 

the  urine,  530 
Aspartie  acid,  relation  to  formation  of 
uric  acid,  475 
,  relation  to  formation  of 

urea,  455 
,  formation  from  proteid, 

21,  302,  307 
,  behavior    in     organism, 
455,  475,  523 
Asphyxiation,   blood   in,    5,    130,    154, 

585 
Assimilation.      See  Absorption. 
Assimilation  limit,  220,  333 
Ass's  milk,  434 
Atmidalbumin,  36 
Atmidalbumose,  36 
Atmid  substances,  36 
Atropin,  action  on  the  elimination  of 
uric  acid,  473 
,  action    on    the    secretion    of 
saliva,  259 
Auto-intoxication,    15 
Auto-oxidation,  8 


Bacteria  urese,  565 

Bactericidal  action,  10,  179 

Banting  cure,  658,  659 

Bases,  nitrogenous,   from  proteids,  21 

Beeswax,  87 

Benzaldehyde,  oxidation,  4 

,   substituted     aldehyde, 
behavior    in    animal 
body,  528 
Benzoic  acid,  formation  from  protein 
substances,  24,  54,  486 
,  passage  of,  into  the  per- 
spiration, 581 
,  behavior  in  the  organ- 
ism, 3,  486,  527 
,  occurrence  in  the  urine, 

489 
,  action    on    metabolism, 

643 
,  substituted     benzoic 
acids,  action  in  body, 
527 
Benzol,  behavior  in  the  animal  body, 

525,  526 
Benzoyl-amido-acetic    acid.      See   Hip- 

puric  acid. 
Benzoj-l-chloride,    behavior    with    car- 
bohydrates,     70, 
212 
,  behavior  with   cys- 
tin,  563 
Benzoyl-cystin,  563 
Bezoar-stone,   325 
Bifurcated  air,  596,  601 
Bile,  222—250 

,  general  chemical  properties,  224 

,  analysis  of,  239,  240 

,  antiseptic    action    of,    318,    319, 

320 
,  constituents  of,  225,  236 

in  diseases,  241 
,  diastatic  action  of,  238,  309 
,  influence  upon  proteid  digestion, 

312,  313 
,  influence  upon  the  emulsification 

of  fats,  311 
,  influence   upon   the   secretion   of 
bile,  224 


INDEX. 


669 


Bile,  influence  upon  the  absorption  of 
fats,  312,  336 
,  influence  ■  upon    the    splitting    of 

neutral  fat,  310 
,  influence  upon  trypsin  digestion, 

301,  311 
,  quantity  of,  222 
,  absorption  of,  224,  339 
,  transit  of  foreign  bodies  into  the, 

241,  242 
,  occurrence  of,  in  urine,  339,  542 — 

544 
,  occurrence  of,  in  contents  of  stom- 
ach, 283,  312 
,  occurrence  of,  in  meconium,  323 
,  composition  of,  239,  240 
,  chemical  formation  of,  242 — 247 
,  secretion  of,  222 
Bile-acids,  225—230 

in  blood,  176,  242 
in  pus,  200 
in  urine,  339,  542 
,  absorption  of.  339 
,  Pettenkofer's  test  for,  226 
Bile-mucus,  224 
Bile-pigments,  233—239 

,  origin  and  formation  of, 

242—247 
,  reactions    of,   234,    235, 

543,  544 
,  passage   into   urine  of, 

543,  544 
,  occurrence      in      blood- 
serum,  125,  176 
,  occurrence  in  egg-shells, 
416 
Bile-salts,  225 
Bilianic  acid,  229 
Biliary  calculi,  247,  248 
Biliary  fistulae,  222 

,  influence  on  putrefac- 
tion   in  the     intes- 
tine, 319 
,  influence  on  the  want 
of  food,  319 
Bilicyanin,  233,  235,  237 
Bilifulvin,  233 
Bilifuscin,  233,  237,  248 


Bilihumin,  233,  237  , 

Biliphoein,  233 
Biliprasin,  233,  237 
Bilirubin,  233 

,  relationship    to    the    blood- 
pigments,  145,  244,  245 
,  relationship  to  haematoidin, 

145,  233,  244 
,  properties,  234 
,  occurrence,  233 
occurrence    in    the    corpora 
lutea,  406 
,  occurrence  in  urine,  542 
,  occurrence  in  tlie  placenta, 
419 
Bilirubin-calcium,  233,  247 
Biliverdin,  properties,  236 
,  occurrence,  208 
,  occurrence     in     egg-shells, 

416 
,  occurrence    in    excrements, 

332 
,  occurrence  in  urine,  542 
,  occurrence  in  the  placenta, 
419 
Birotation,  64 

Bismuth,  passage  of,  into  the  milk,  443 
Bitch's  milk,  434 
Biuret,  459 

Biuret,  reaction,  27,  459 
Blister  fluid,  196 
Blood,  111-179 

,  general  behavior.  111,  152,  153 

,  coagulation  of,  153 — 161 

,  gases    of.       See    Chemistry    of 

respiration.  Chapter  XVII. 
,  quantitative  analyses,  1G3 — 169 
,  arterial   and  venous,   130,   169, 

584,  585.  596,  601 
,  defibrinated,  112 

in  asphyxiation,  5,  130,  151,  5S5 
,  quantity  in  the  body,  177 
,  detection,  chcmico-legal,  145 
,  behavior  in  starvation,  172,  624 
,  composition     under     abnormal 

conditions,  173 — 177 
,  composition  under  physiological 
conditions,  169—173 


670 


INDEX. 


Blc^d  in  urine,  538—540 

in  gastric  contents,  283 
,  transfusion  of,  173,  178 
,  loss  of,  177 
Blood-casts,  538 
Blood-clot    (placenta   sanguinis),    112, 

153 
Blood-corpuscles,  white,   149,   150,   174 
,  white,     behavior     in 
the   coagulation   of 
blood,  150,  156—158 
,  white,      relationship 
to     the     formation 
of  uric  acid,  476 
,  red,   128—130 
,  red,  in  urine,  538 
,  red,  composition,  127, 
168,  174 
Blood-pigments,   130—149 

in  bile,  242 
in  urine,  538 — 540 
Blood-plasma,  113—122 

,  composition  of,  126,  107 
Blood-plates,  149,  151  " 

,  importance    in     coagula- 
tion, 156 
Blood-serum,  112,   122—127 

,  globulicidal  action,  178 
,  composition  of,  126,  167 
Blood-spots,   145 
Blood-sweat,  582 
Blue  stentorin,  578 
Bone  and  bony  tissue,  348 — 354 

in      starvation, 
513,  623 
Bone-earths,  349,  350 
Bone,  softening  of,  352 
Bonellin,  578 
Borax,  action  on  metabolism,  643 

on  trypsin  digestion,  301 
Borneol,  529 

Bottcher's  spermin  crystals,  404 
Bottger-Almen's  test  for  sugar,  69,  546 
Bowman's  disks,  361 
Brain,  390—402 
Bread,  behavior  in  the  stomach,  277 

,  excrement  after,  321 
Bromadenin,  103 


Bromanil,  24 

Bromhypoxanthin,   103 

Bromine  compounds,  passage  of,  into 

the  saliva,  260 
Bromoform,  24 
Brunner's  glands,  289 
Buccal  mucus,  253 
Buffy  coat,  153 
Bufidin,  579 

Bull,  spermatozoa  of,  405 
Bursse  mucosse,   197 
Butalanin,  57 
Butter-fat,  425,  435 

,  calorific  value  of,  617 
,  absorption  of,  336 
Buttermilk,  434 
Butyl    alcohol,     behavior     in    animal 

body,  524 
Butyl-chloral   hydrate,  behavior  in  ani- 
mal body,  524 
Butyric  acid  in  contents  of  stomach, 
283,  288 
in  gastric  juice,  264 
in  milk  fat,  424,  435 
Butyric-acid  fermentation,  5,  69 

in  intestine, 
316 
Byssus,  18,  57 

Cadaverin,  14 

Caflfein,  action  on  the  muscles,  375 

Calcium,  lack  of,  in  food,  352,  629 

,  occurrence.      See  various  tis- 
sues and  fluids. 
Calcium  salts,  significance  for  the  co- 
agulation    of     blood, 
116,  117,  159 
,  significance  for  the  co- 
agulation     of      milk, 
426 
,  significance  for  the  co- 
agulation   of    muscle 
plasma,  363 
See    also    various    cal- 
cium salts. 
Calcium  carbonate  in  urine,  447 

in  urinary  calculi, 
570 


INDEX. 


671 


Calcium  carbonate    in    urinary    sedi- 
ments, 507 
in  bones,  349,  350, 

353 
in  tartar,  261 
Calcium  formate,  enzymotic  decompo- 
sition, 11 
Calcium  oxalate  in  urine,  481,  483 

in  urinary  sediments, 

482,  567 
in  urinary  calculi. 
570 
Calcium    phosphate,    relation    to    co- 
agulation   of    fibrinogen,    117,     118, 
159 
Calcium  phosphate,  relation  to  coagu- 

tion  of  casein,  426 
Calcium  phosphate,  occurrence  in  in- 
testinal calculi,  325 
Calcium  phosphate  in  urine,  447,  512, 

513,  519 
Calcium   phosphate    in     urinary    sedi- 
ments, 567 
Calcium  phosphate  in  urinary  calculi, 

570 
Calcium  phosphate  in  salivary  calculi, 

261 
Calcium  sulphate  in  urinary  sediments, 

567 
Calories  of  the  food,  617.  618 

of  various  dietaries,  653 
Campho-glycuronic  acid,  506,  529 
Camphor,  behavior  in  the  body,  506, 

529 
Camphoral,  529 
Cane-sugar,  72,  73 

,  inversion  of,  290,  309,  332 
,  caloric  value  of,  617 
,  absorption  of,  339 
,  b  e  h  a  vi  o  r  to  intestinal 

juice,  290 
,  behavior  to  gastric  juice, 
272 
Capillary   endothelium,   secretory   sig- 
nificance of,  187,  189 
Capric  acid,  424,  435 
Caproic  acid,  formation    from    phenol, 
7,  525 


Caproic  acid,  occurrence  in  fatty  tis- 
sue, 354 
,  occurrence    in    milk-fat, 
424,  435 
Caprylic  acid,  424 
Caramel,  68,  73 
Carbamic  acid,  467 

in  the  blood,  125,  456 
in  the  urine,  456,  467 
,  poisonous  action  of,  456 
Carbamic-acid     ethj'lester,     467.       See 

Urethan,  467 
Carbolic  acid,  action  on  pepsin  diges- 
tion, 270 
See  also  Phenol. 
Carbolic  urine,  493 
Carbohaemoglobin,  139 
Carbohydrates,  59—80 

,  importance    for    the 
formation  of  fat,  358 
,  importance    for    the 
formation    of   glyco- 
gen, 214,  215 
,  imjjortance  for  muscu- 
lar activity,  378,384, 
385 
,  action  on  the  metab- 
olism    of     proteids, 
630,  639 
,  action  on  putrefaction, 

318,  490 
,  absorption  of,  332,  334 
,  inadequate    supply    of, 
630 
See    also    the    various 
carbohydrates. 
Carbon  dioxide  in  the  blood,  583 — 590 
in  diabetes,  590 
in  poisoning  witli  min- 
eral acids,  590 
in    the    intestine,    314 

316 
in  the  lymph,  182,  590 
in  the  stomach,  278 
in  the  muscles  in  ac- 
tivity  and    at    rest, 
378,  384 
in  rigor  mortis,  376 


672 


INDEX. 


Carbon  dioxide  in  secretions,  591 

in  transudations,  592 
,  binding  of  CO    in  the 

blood,    586—590 
,  action  on  the  secretion 

of  gastric  juice,  262 
,  action    on    the    secre- 
tion    of     pancreatic 
juice,  296 
,  tension  in  blood,  601, 

602 
,  tension  in  tissues,  603 
,  tension  in  the  lymph, 

182 
,   tension    in    transuda- 
tions, 592 
elimination,      depend- 
ence   on    the    exter- 
nal temperature,  650, 
651 
elimination      in      ac- 
tivity   and    at   rest, 
378,  379,  384,  647— 
650 
elimination     by      the 

skin,  582 
elimination    in     vari- 
ous ages,  646,  647 
haemoglobin,  139 
Carbon-monoxide  poisoning,   139,   176, 

372 
Carbon-monoxide  poisoning,  action  en 

lactic  acid  formation,   372 
Carbon-monoxide  poisoning,  action  en 

the  elimination  of  nitrogen,  453 
Carbon-monoxide  poisoning,  action  on 

the  elimination  of  sugar,  220,  372 
Carbon-monoxide    blood    test,    Hoppe 

Seyler's,  139 
Carbon-monoxide  haemoglobin,  133, 140 
Carbon-monoxide  methsemoglobin,  139 
Carminic  acid,  578 
Carnic  acid,  366,  368 
Carniferrin,  368 
Carnin,  102,  367 

in  urine,  484 
Carp,  sperma  of,  100,  106,  406 
Cartilage,  343—348 


Cartilage,  amount  of  ash  in,  347 

,  behavior    to    gastric    juice,. 

271,  276 
,  behavior  to  pancreatic  juice,, 
307 
Cartilage  gelatin,  53,  343 
Cartilage  of  the  knee-joint,  347 
Casein,  origin,  420,  441 

from  woman's  milk,  436 
from  cow's  milk,  425 
,  quantitative  estimation,  431 
,  behavior  with  rennet,  273,  426, 

436 
,  behavior  with  gastric  juice,  270,, 

277,  427,  436 
,  caloric  value  of,  617 
,  phosphorus  of,  427 
Caseinogen,  427 
Caseoses,  36 
Castor  bean,  15 
Castoreum,  579 
Castorin,  579 
Cataract,  402 

Catheterization  of  the  lungs,  595,  601 
Cat's  milk,  434 
Cells,  animal,  88—110 
Cell  constituents,  primary  and  second- 
ary, 89 
Cell  fibrinogen,  102 
Cell  globulin,  90,  129 
Cell  membrane,  92 
Cell  nucleus,  96 

,  relation  to  fibrin  coagu- 
lation, 151,  156,  157 
Cellulose,  79 

,  fermentation  of,  310,  317 
,  occurrence    in    tuberculosis^ 

605 
,  a  c  t  i  o  n    on   absorption    of 
foods,  331 
Cement,  353 
Cerebrin,  72,  394 

,  properties  and  behavior,  394^ 
395 
in  pus,  199 
Cerebrosides,  392,  393 
Cerebrospinal  fluid,  195 
Cerolein,  87 


INDEX. 


673 


Cerotic  acid,  87 
Cerumen,  579 
Cetin,  86 
Cetyl  alcohol,  87 
Chalaz^,  413 

Charcot's  crystals,  175,  404,  606 
Charge  of  the  stomach  with  pepsin,  275 
of  the  pancreas  with  pepsin,  202 
Cheese,  277,  427 
Cheno-taurocholic  acid,  228 
Chief  cells,  261,  274,  275 
Children's  urine,  447,  454,  483 
Chitin,  56,  58,  574 

,  behavior  in  trypsin  digestion, 
308 
Chitosan,  575 
Chloral  hydrate,  absorption,  339 

,  behavior     in     animal 
body,  506,  524 
Chlorate,  poisoning  with,  136,  538 
Chlorazol,  24 
Chlorbenzol,  behavior  in  animal  body, 

529 
Chlorides,    elimination    by    the    urine, 
127,  509,  510 
,   elimination   by   the   sweat, 

580,  581 
,    action    on    proteid    metab- 
olism, 642,  643 
,   insufficient   supply    of,   627 
See  also  the  various  fluids 
and  tissues. 
Chlorocruorin,  148 

Chloroform,  action  on  the  elimination 
of  chlorides,  510 
,  action  on  the  muscles,  375 
Chlorophan,  399 
Chlorophyll,  2 
Chlorosis,  174 
Chlorphenylcystein,  529 
Chlorphenylmercapturic  acid,  529 
Chlorrhodinic  acid,  200 
Cholagogues,  224 
Cholalic  acid,  228 

,  relation    to    cholesterin, 
248 
Cholanic  acid,  230 
Cholecyanin,  234,  235 


Choleglobin,  246 

Choleic  acid,  230 

Cholepyrrhin,  233 

Cholera,  blood  in,  173,  175,  176 

,  contents  of  intestine  in,  324 
,  sweat  in,  581 
,  ptomaines  in,  14 
Cholera    bacilli,    behavior    in    gastric 

juice,  282 
Cholesterilin,  248 
Cholesterin,  248 

in  expectorations,  606 
in  bile,  238,  239,  240 
in  biliary  calculi,  248 
in  the  brain,  391,  397 
in  the  urine,  562 
,  importance  of,  in  the  life 
processes    of    the    cells, 
96 
Cholesterin  calculi,  248 
Cholesterin  fat  as  protective  fat,  578 
Cholesterin-propionic  ester,  249 
Choletelin,  233,  236 

,  relation  to  urobilin,  501 
Cholin,  15,  93,  238 
Cholohaematin,  237 
Choloidic  acid,  230 
Chondrigen,  343 
Chondrin,  56,  343 

,  in  pus,  200 
Chondrin  balls,  346 
Chondrosin  from  chondroitin  sulphuric 
acid,  345,  506 
from  gelatinous  sponges,  47 
Chondroitic  acid,  344 
Chondroitin,  345 
Chondroitin-sulphuric    acid,    344,    506. 

574 
Chondromucoid,  47,  344 
Chorda  saliva,  252 
Choroid  coat,  402 

,  pigment  of,  576 
Christensen  and  Mygge's  method  for 
the  approximate  estimation  of  pro- 
teid in  urine,  537 
Chromatin,  96 
Chromhidrosis,  581 
Chromogens  in  urine,  499 


674 


INDEX. 


Chromogens  in  the  supra-renal  capsule, 

205 
Chrysophanic    acid,    action    on    urine, 

530 
Chyle,  180—183 
Chylopericardium,  192 
Chyluria,  561 
Chyme,  276 

,  investigation,  284 — 289 
Chymosin,  13,  272,  426 
in  urine,  508 
Cinnamic  acid,  behavior  in  the  animal 

body,  486 
Citric  acid  in  milk,  425,  433,  437 
Cleavage  processes.    See  Splitting  proc- 
esses. 
Coagulation    of   the    blood,    111,    112, 
115  —  119,    154—163, 
169,  170,  171,  175 
,  intravascular,  162 
of  milk,  422,  426,  436 
of     muscle-plasma,     361, 
363,  376 
Cobalt    hydrocarbonate,    behavior    to 

gastric  juice,  264 
Coccygeal  glands,  579 
Cochineal,  578 
Coefficient,  Haser's,  521 

,  respiratory,  384,  615,  623 
,  urotoxic,  509 
Coffee,  action  on  metabolism,  644 
Collagen,  18,  53,  342,  343,  346,  348 
Collidin,  14 
Colloid,  47,  407,  408 
Colloid  corpuscles,  407 
Colloid  cysts,  407 
Coloring  matters.     See  Pigments. 
Colostrum  of  woman's  milk,  438 

of  cow's  milk,  433 
Colostrum  corpuscles,  433,  442 
Combustion,  physiological,  6 
Comma    bacillus,   behavior    in   gastric 

juice,  282 
Compound  proteids,  18,  43 — 49 

in  protoplasm,  91, 
101,  292,  420 
Conchiolin,  18,  57 
Conerements.     See  various  calculi. 


Cones  of  the  retina,  pigment  of,  398 
Conglutin,  calorific  value,  517 
Connective  tissues,  342 
Copaiva  balsam,  action  on  the  urine, 

530 
Copper  in  the  blood,  125,  168 
in  the  bile,  238 
in  biliary  calculi,  248 
in  hsemocyanin,   148 
in  protein  substances,  17 
in  turacin,  577 
Cornea,  348,  402 
Cornein,  18,  57 
Cornicrystallin,  57 
Corpora  lutea,  406 
Corpulence,  diet  cures  for,  658,  659 
Corpuscula  amylacea,  395 
Cow's  milk,  421—434 

,  general  behavior.  42^,  422 

,  analysis  of,  430—433 

,  constituents,       inorganic, 

432—433 
,  constituents,  organic,  423 

—430 
,  checking  action  on  putre- 
faction, 318,  490 
,  coagulation  with  rennet, 

273,  422,  426 
,  behavior  in  the  stomach, 

276,  281,  282 
,  composition  of,  432 — 434 
Cream,  434 

Creatin,  relation  to  the  formation  of 
urea,  367,  454 
,  relation  to  muscular  activity, 

381,  384 
,  properties  and  occurrence,  366, 
367 
Creatinin,  relationship  to  muscular  ac- 
tivity, 381,  384,  467 
,  properties    and    occurrence, 

467 
,  zinc  chloride,  468 
Cresol,  22,  314,  489,  490 
Cresol-sulphuric  acid,  489,  490 
Crotonic  acid,  561 

Crotyl  alcohol,  relationship  to  forma- 
tion of  glycogen,  214 


INDEX. 


675 


Cruor,  112 

Crusoereatinin,    369 

Crustaceorubin,  578 

Crusta    inflammatoria    or    phlogistica, 

153,  175 
Crystalbumin,  401 
Crystalfibrin,  401 
Crystallin,  18,  401 
Crystalline  lens,  400^102 
Cumic  acid,  527 
Cuminuric  acid,  528 
Curare  poisoning,  action  on  muscular 
tonus,  378 
,  action    on    elimina- 
tion of  sugar,  220 
Cyanmethsemoglobin,  140 
Cyanocrystallin.  417,  578 
Cyanogen  in  proteid  molecule,  4 
Cyanuric  acid,  459,  471 
Cyanurin,  500 
Cymol,  527 
Cystein,  529,  562 

,  conjugation  in  animal  body, 
529 
Cystin,  properties,  562 

,  occurrence  in  urine,  507,  509, 

562 
,  in  urinary  calculi,  570 
,  in  urinary  sediments,  568 
,  in  sweat,  581 
,  in  trypsin  digestion,  563 
Cystinuria,  14,  509,  562 
Cysts,  tapeworm,  196 
,  ovarial,  406—410 
,  thyroid,  204 
Cytin,  102 

Cytoglobin,  18,  91,  102,  157 
Cytoplasm,  90 
Cytosin,  100 

Damaluric  acid,  509 
Damolic  acid,  509 
Dehydrocholalic  acid,  229 
Dehydrocholeic  acid,  230 
Delomorphic  or  parietal  cells,  261,  273, 

275 
Denige's  reaction  for  uric  acid,  478 
Dentin,  350,  353 


Descemet's  membrane,  47,  348 
Desoxycholalic  acid,  229,  230 
Deuteroalbumose,  36,  40,  535 
Deuteroelastose,  52 
Deuterogelatose,  55 
Devoto's   method   of   determining   the 

quantity  of  proteid,  29,  535 
Dextrins,  77,  78 

,  formation  from  starch,   78, 

256 
,  loading    the    stomach    with, 

275 
,  occurrence  in  the  contents  of 
the  stomach,  277 
in  muscles,  271 
in  portal  blood,  170,  332 
Dextrin-like  substances  in  the  urine, 

505 
Dextrose,  67—71 

in  the  blood,  123   170,  217, 

218—220 
in  the  urine,  123,  218,  544— 

554 
in  the  lymph,  181 
in  the  muscles,  371 
,  preparation  of,  71 
,  caloric  value  of,  617 
,  detection  of,  71,  514—549 
,  reactions  of,  68,  69,  70 
,  absorption  of,  339,  340 
,  quantitative    estimation    in 
,  the  urine,  549 — 554 
Diabetes  mellitus,  219,  220,  221,  293, 
544 
,  elimination  of  NH3 
by  the  urine  in, 
518 
,  relation  of  the  liver 

to,  219—221 
,  relation  of  the  pan- 
creas     to,      221, 
293 
,  to    elimination    of 
sugar,    blood    in, 
176,  221 
,  quantity    of   sugar 
in  the  blood  in, 
176,  219 


676 


INDEX. 


Diabetes  mellitus,  urine  in,  447,  522, 
544 
,  carbon    dioxide    in 
the  blood  in,  590 
,  oxybutyric  acid  in 
the  blood  in,  590 
,  oxybutyric  acid  in 
the  urine  in,  518, 
560 
Diacetic  acid,  559 

in  urine,  556,  557 
Diagonal  disks  of  the  muscles,  361 
Diamid,  poisoning  with,  483 
Diamins  in  the  urine,  14,  509,  563 

in  the  intestinal  contents,  14, 
563 
Diamido-acetic  acid,  21 
Diamido-caproic  acid,  21 
Diamido-valerianic   acid,    524 
Diarrhoea,  324,  334 

,   action   on   the   quantity   of 
urine,  522 
Diastatic  enzymes,  12,  256,  297.      See 

also  Enzymes. 
Diastase  in  the  blood,  124 
Dicalcium  casein,  425 
Diet  for  various  classes  of  people,  653 
Diet  cures  for  corpulence,  658 
Digestion,  251—341 
Digestibility   of   food-stuflfs,   279,   280, 

330,  331,  334,  335 
Digestion  leucocytosis,  172,  473,  476 
Dimethyl  carbinol,  behavior  in  animal 

body,  524 
Dimethylketone.     See  Acetone. 
Dioxyaceton,  67 
Dioxybenzol,  526 
Dioxynaphthalin,   526 
Disaccharides,  72 

in  urine,  333,  555 
Distearyllecithin,  93 
Distribution  of  blood  in  the  organs, 

179 
Doeglic  acid,  85 
Dog's  milk,  434 
Dolphin  milk,  434 
Donne's  pus  test,  541 
Dotterplattchen,  24,  411 


Dulcite,  61 

,   relation   to  glycogen   forma- 
tion, 214 
Dysalbumose,  36 
Dyslysine,  230 
Dyspeptone,  271 

Dyspnoea,    action    on    proteid    trans- 
formation, 453,  648 

Earthy  phosphates,  elimination  by  the 
urine,  513,  514,. 
519 
,  solubility  in  pro- 
teid fluids,  353 
,  occurrence  in  bone- 
ash,  348—350 
,  occurrence  in  cal- 
culi,    247,     261,. 
325,  570 
,  occurrence  in  sedi- 
ments, 566—568 
See    also     various 
earthy      p  h  o  s- 
phates. 
Ebstein's  diet  cure,  658 
Echinochrom,  148 
Echinococcus  cysts,  cyst  wall,  575 

,  cyst  contents,  196 
Eck's  fistula,  456 
Eel,  serum  of,  126 

,  flesh,  387 
Egg,  410 

,  hen's,  410—419 
,  absorption  in  the  intestine,  331 
,  incubation,  418 
Egg  albumin  (see  Ovalbumin),  413 
Egg-shell,  416 
Ehrlich's    test    for    bile-pigments,    544 

urine  test,  561 
Eiselt's  reaction,  541 
Elaidic   acid,   85 
Elaidin,  84 
Elastin,  18,  51 

,  behavior  to  gastric  juice,  271 
,  behavior  to  trypsin,  307 
Elastin  albumoses,  52 
Elastin  peptone,  52 
Electrosyntheses,  7 


INDEX, 


677 


Eleidin,  573 

Elepliant  bones,  349 

Elephant  milk,  434 

Elephant  tusk,  354 

Ellagic  acid,  326 

Eraulsin,  12 

Kmydin,  417 

Enamel,  353 

Encephalin,  392,  394 

Endolymph,  402 

Energy,  potential  of,  food-stuffs,  616 — 

619 
Enzymes,  in  general,  10 — 13 

,  diastatic,  in  pancTtatic  juice. 

296,  297 
,  diastatic,  in  blood,  124,  125, 

217 
,  diastatic,  in  bile,  238,  309 
,  diastatic,  in  urine,  50S 
,  diastatic,   in   the   liver,   217, 

218 
,  diastatic,  in  lymph,  181 
,  diastatic,  in  muscles,  366 
,  diastatic,  in  the  secretion  of 
the   mucous   membrane   of 
the  intestine,  289,  290 
,  diastatic,  in  saliva,  255 
,  proteolytic,   in    the    mucous 
membrane  of  the  intestine, 
290 
,  proteolytic,     in     the     urine, 

508 
,  proteolytic,  in  the  stomach, 

261,  264,  265 
,  proteolytic,  in  the  pancreas, 

296,  299.  300 
,  proteolytic-,  in  t!ie  plant  king- 
dom, 265 
,  proteolytic,  in  the  lower  ani- 
mals, 265 
,  steatolytic.  13,  297,  298,  299 
,  coagulating.     See  Fibrin  fer- 
ment and  Rennin. 
,  urea  splitting,  565 
Eplguanin,   484 
Episarkin,  102,  485 
Erucic  acid  absorption,  335 

,  synthesis  from  erucin,  335 


Erythrit,  relation  to  glycogen  forma- 
tion, 214 
Erythro-dextrin,  78,  256 
Erythropsin.     See  Visual  purple. 
Esbach's  estimation  of  proteid,  536 

urea,  466 
Esters,  action  on  the  pancreatic  juice, 

298 
Ethal,  87 
Ether,  action  on  blood,  128 

,  action   on   secretion    of   gastric 

juice,  262 
,  action  on  the  muscles,  375 
,  action  on  the  secretion  of  pan- 
creatic juice,  295 
Ethereal   sulphuric   acids   in   the   bile, 

240 
Ethereal  sulphuric  acids  in  the  urine, 

314,  489-^96,  525,  529 
Ethereal  sulphuric  acids  in  sweat,  581 
Ethereal  oils,  action  on  muscles,  375 
Ethyl    alcohol,  formation  in  intestine, 
313 
,  absorption,  339 
,  passage  of,  into  milk, 

443 
,  behavior  in  animal  or- 
I         ganism,  643 
,  action  on  secretion  of 
I         gastric  juice,  262 
,  action  on  the  muscles, 

375 
,  action  on  metabolism, 

643 
,  action     on     digestion, 
270,  280 
Ethyl    benzol,    behavior    in    organism, 

526 
Ethylen  glycol,  relationship  to  forma- 
tion of  glycogen,  214 
Ethylenimin.     See  Spermin. 
Ethylidene-lactic  acid,  371.      See  also 

other  lactic  acids. 
Euxanthic  acid,  506 
Euxanthin,  506 
Excrements,  320—324 

in   dogs  with   biliary   fis- 
tula, 319 


678 


INDEX. 


Excrements    in  starvation,  611 

,  elimination    of    water 
with,  610 

Excreta  of  the  body,   608—616 

,  division  among  the   various 
excretions,  609 

Excretin,  323 

Excretolic  acid,  323 

Exostosis,  352 

Expectorations,  605,  606 

Extinction   coefficient,   147,   148 

Extracellular  action  of  enzymes,  11 

Exudations,  188—197 

Eye,  397—403 

Faeces.     See  Excrements. 
Fat,  origin  in  the  body,  355—358,  632, 
633 
,  general  properties,  detection,  and 

occurrence  of,  81 — 87 
,  emulsification   of,   290,   298,   299, 
310,  311,  334,  336—338 
in  blood-serum,  122,  172,  175 
in  chyle,  183 
in  yolk  of  egg,  412 
.in  pus,  199 

in  excrements,  336,  338 
in  fatty  tissue,  354 
in  bile,  238,  239,  240 
in  the  brain,  391 
in  the  urine,  561,  562 
!  in  the  bones,  350 
in  milk,  422,  423,  424,  431,  433, 
434,  435,  442 
,  caloric  value  of,  616,  617 
'  ,  nutritive  value  of,  616—619,  621, 
637—642 
,  rancidity,  83 

,  absorption  of,  334—336,  341 
,  behavior      to      intestinal      juice, 

290 
,  behavior  to  gastric  juice,  278 
,  behavior  to  pancreatic  juice,  298, 

337 
,  saponification  of,  82,  85,  298,  310, 

338 
,  action   on   the  secretion  of  bile, 
223 


Fat-metabolism     in    activity    and    at 
rest,  383—385 
in     starvation,     621, 

622 
with    various    foods, 
630,  632,  637—644 
Fat-cells,  354 
Fat-sweat,  579 

Fatty  acids,  general  properties,  detec- 
tion    and     occurrence, 
82—86 
,  absorption  of,  334 — 336 
,  synthesis  to  neutral  fats,. 
335,  355 
Fatty  degeneration,  208,  356 
Fatty  infiltration,  208 
Fatty  series,  behavior  of  the  respective 

members  in  the  animal  body,  523 
Fatty  tissue,  354 

,  behavior  with  gastric 
juice,  272,  278 
Feathers,  49,  577 
Fehling's  solution,  69,  549—552 
Fellic  acid,  230 
Fermentation,  5,  10,  64,  68 

in  the  intestine,  313 
in  urine,  505,  564,  565 
in  contents  of  stomach,. 

277,  281,  283 
See    also    various    fer- 
mentations,    Alcohol 
f e mi e. station,  etc. 
Fermentation   test   in   the   urine,   547^ 

553 
Fermentation    lactic    acid,    properties^ 

occurrence,  etc.,  371,  373 
Fermentation  lactic  acid  in  the  brain, 

392 
Fermentation  lactic  acid  in  the  stom- 
ach contents,  277 
Fermentation  lactic  acid  in  the  gastr  c 

juice,  264 
Fermentation  lactic  acid,  formation  of, 

in  the  souring  of  milk,  422 
Fermentation  lactic  acid  in  urine  fer- 
mentation, 564 
Fermentation  lactic  acid,  detection  of, 
in  stomach  contents,  285 


INDEX, 


679 


Ferments,    in    general,    10.     See    also 

various   enzymes. 
Fever,  elimination  of  ammonia  in,  517, 
518 
,  elimination  of  uric  acid,  474 
,  elimination  of  urea,  454 
,  elimination  of  potassium  salts, 

517 
,  metabolism  of  proteids  in,  454, 
474 
Fibres,  elastic,  in  sputum,  606 

,  reticulate,  342 
Fibrin,  18,  112 

,  occurrence  of,  in  transudations, 

188,  191—196 
,  properties  of,  114 
,  Henle's,  403 
Fibrin  coagulation,  114 — 119,  153 — 163 
Fibrin  calculi,  325 
Fibrin  digestion,  267 — 271 
Fibrine  soluble.     See  Serglobulin. 
Fibrin  ferment,  13,  115,  116,  117,  157— 

163 
Fibrin  formation   (see  Fibrin  coagula- 
tion), 114—119,  153—163 
Fibrin  globulin,  117,  122 
Fibrinogen,  18,  91,  102,  113,  1.58,  160, 

161,  181,  190 
Fibrinolysis,  115 

Fibrinoplastic     substance.       See     Ser- 
globulin. 
Hbroin,  18,  57 

Filtration,  relation  to  absorption,  340 
Fish-eggs,  24,  417 
Fish-bones,  351 
Fish-scales,   105 
Fish  air-bladder,  105,  603 
Flesh,    metabolism    of,    in    starvation, 
621 
,    metabolism    of,    with    various 

foods,  630—642 
,    accumulation  of,  with  various 
foods,  630,  631,  633,  634,  636, 
638—641 
Flesh  quotient,  388 
Fluorine  in  bones,  349 

in  enamel,  354 
Fly-maggots,  formation  of  fat  in,  357 


Food,  influence  of,  on  the  secretion  of 

intestinal  juice,  289 
,  influence  of,  on  the  secretion  of 

bile,  223 
,  influence  of,  on  the  secretion  of 

gastric  juice,  262,  263 
,  influence  of,  on  the  secretion  of 

pancreatic  juice,  295 
,  influence  of,  on  the  elimination 

of  ammonia,  517 
,  influence  of,  on  the  elimination 

of  uric  acid,  473 
,  influence  of,  on  the  elimination 

of  urea,  452,  453,  621 
,  influence  of,  on  the  elimination 

of  CO  ,  615,  622 

2 

,  influence  of,  on  the  elimination 
of  mineral  bodies,  510,  512,517 
,  influence   on   metabolism,   625 — 
642 
rich  in  proteid,  630—637 
,  mixed,  637—642 
,  insufficient,  625—630 
Food-stufi's,   necessary,   607 

,   heat    of    combustion    of, 
616—619 
Formaldehyde,     formation     of     sugar 

from,  67 
Formic  acid  in  butter,  424 

in  gastric  contents,  288 
,  p  a  s  s  a  g  e    of,    into    the 
urine,  505,  523 
Formose,  67 

Frog's  eggs,  membrane  of,  44 
Fructose,  60,  61,  63,  66,  67,  71,  77 

in  urine  (see  Laevulose),  554 
Fruit-sugar.     See  Fructose, 
Fumaric  acid,  24 
Fundus-glands,  261,  273 
Fungi,  glycogen  therein,  210 
Fiirbringer's  albumin  reagent,  534 
Furfuracryluric  acid,  524 
Furfurol  from  glycuronic  acid,  507 
from  pentoses,  65 
,  relation  to  Pettenkofer's  test 

for  bile-acids,  226 
,  reagent  for  urea,  459 
,  behavior  in  the  body,  524 


680 


INDEX. 


Fuscin,  399,  400 

Galactonic  acid,  72 
Galactose,  61,  66,  72,  80,  428 
from  cerebrin,  394 
from  vegetable  bodies,  443 
,  relation  to  glycogen  forma- 
tion, 216 
Gallic  acid  in  urine,  497 
Gallois's  inosit  test,  370 
Gas,  exchange  of,  with  various  ages, 
646,  647 
,  exchange  of,  by  the  skin,  582 
,  exchange  of,  in  starvation,  615, 

622,  624 
,  exchange    of,    in    various    condi- 
tions of  the  body,  384,  622,  624, 
643,  644 
,  exchange  of,  in  muscles,  376,  378, 

384 
,  exchange  of,  with  various  foods, 

643,  644 
,  exchange  of,  abstinent  value  of, 
624,   625,   645 
Gases  of  the  blood,  583—590 

of  the  intestinal  contents,  316 

of  the  bile,  241,  591 

of  the  urine,  519,  592 

of  the  hen's  egg,  417 — 419 

of  the  lymph,  182.  590 

of  the  milk,  433,  592 

of   the   muscles,    375,    370,    378, 

384 
of  the  transudations,  190,  592 
from  woman's  milk,  438 
Gastric  catarrh,  283 
Gastric  contents.     See  Chyme. 
Gastric  fistula,  262 
Gastric  juice,  262 

,  secretion  of,  262,  263 
,  estimation    of    acidity, 

284,  286—288 
,  relation  to  intestinal  pu- 
trefaction, 320 
,  artificial,  267 
,  action  of,  34,  35,  267— 
270,276—283,427,436 
Gelatin,  54 


Gelatin,  relation  to  the  formation  of 
glycogen,  214 
,  putrefaction  of,  54,  314 
,  nutritive  value  of,  636 
,  behavior  to  gastric  juice,  271 
,   behavior  to  pancreatic  juice, 
307 
Gelatin- forming   substances    (see   Col- 
lagen), 53 
Gelatin  peptones,  55 
Gelatin  sugar.<    See  GlycocoU. 
Gelatinous  tissue,  343 
Gentisic  acid,  498 
Gentisic  aldehyde,  498 
Germ  of  the  hen's  egg,  410 
Globin,  140 

Globulieidal  bodies  in  serum,  178 
Globulins,  18 

,  general  properties,  30 
in  urine,  534 
in  protoplasm,  90 
See  also  the  various  globu- 
lins. 
Globulin-plates,  151 
Globuloses,  36 
Glucase  in  the  blood,  124 
Glueocyanhydrin,  61 
Glucoheptose,  61 
Gluconic  acid,  61 
Gluco-proteins,   30 
Glucosamin  from  chitin,  574 
in  cartilage,  345 
Glucosan,  68 
Glucose.     See  Dextrose. 
Glucosoxime,  61 
Glutamic  acid,  21 
Gluten  protein,   42 
Glutin.     See  Gelatin. 
Glycerin,  relation  to  the  formation  of 
glycogen,  214 
,  action  on  the  elimination  of 

uric  acid,  473 
,  solvent  for  enzymes,  11 
Glycerin  aldehyde,  67 
Glycero-phosphoric  acid,  93,  175,  201, 
238 
in  urine,  505, 
508 


INDEX. 


681 


dycin.    See  Glycocoll. 
Olycocholic  acid,  225,  226,  227,  240 
,  properties  of,  227 
,  quantity  in   e  x  c  r  e- 
ments,  317 
in  various  animal 
biles.  241 
,  absorption  of,  340 
,  beha\ior  in  the  pu- 
trefaction    in     the 
intestine,  317 
OlycocoU,  properties  of,  231 

,  formation  from  gelatin,  54, 

314 
,  formation    from    other   pro- 
tein  substances.   54 — 56 
,  relation  to  the  formation  of 

uric  acid,  471,  475 
,  relation  to  the  formation  of 

urea,  455,  523 
,  syntheses  with,  3,  485,  486, 
524,  527 
Glycogen,  77,  89,  210—219 

,  origin  of,  213—217 

,  general    chemical    behavior, 

211,  212 
,  relation  to  muscular  activ- 
ity, 378—385 
,  relation  to  rigor  mortis.  37G 
,  relation  to  the  formation  of 

sugar,  217 — 222 
,  occurrence    of,    in    sputum, 

606 
,  occurrence    of,    in    muscles, 

370 
,  occurrence  of,  in  the  lungs, 

605 
,  occurrence   of,    in   p  r  o  t  o  - 
plasm,  90,  95,   150,  199 
Glycolysis,  123,  181,  294 
Glycolytic  enzyme,  124 
Glyco-proteids,  18,  31,  43,  92 
Glycosuria,  123,  219,  220,  544 
Glycosuric  acid,  498 
Glycuron,  507 

Glycuronic  acid,  relation  to  glycogen 
formation,  214 
,  properties  of,  506 


Glycuronic  acid,  conjugated,  491,  493, 
496,  506 
,  conjugation     of,     in 
the  body,  524,  529 
,  origin  of,  524 
Glyoxyl  diureid.     See  AUantoin. 
Gmelin's  test  for  bile-pigment,  235 

test      for      bile-pigment      in 
urine,  543 
Goat-milk,  434 
Goose-fat,  absorption  of,  335 
Gout,  elimination  of  uric  acid  in,  472, 

474 
Graafian  follicles,  406 
Grape-moles,   419 
Gravimetric   estimation   of  proteid   in 

urine,  536 
Guaiacum  blood  test,  539 
Guanin,  properties  and  occurrence,  105 
in  urine,  484 
,  quantity  in  liver.  208 
,  quantity  in  pancreas,  292 
,  quantity  in  sperma,  406 
Guanin  calcium,   105 
Guanin  gout,  105 
Guano,  105,  472 
Guano  bile-acids,  227 
Guanovulit,  417 
Gulonic  acid  lacton,  506 
Gulose,  66,  71 
Gums,  various,  65 
Gum,  animal,  45 

in  urine,  505 

Haemataerometer,  596 
Haematin,  141 

,  relation  to  bilirubin,  245 
,  relation  to  urobilin,  245,  499 
,  properties  of,  141 
Hsematinometer.  146 
Haematoblasts,  151 
Hgematochlorin,  419 
Hsematocrit,  165 
Haematocrystallin.       See     Oxyhaemo- 

globin. 
Haematoidin,  145 

,  relation  to  bilirubin,  145, 
233,  243,  244 


682 


INDEX. 


Hsematoidin,  properties  of,  145 

,  occurrence  in  expectora- 
tions, 606 
,  occurrence  in  corpora  lu- 

tea,  406 
,   occurrence      in      excre- 
ments, 322 
,  occurrence  in  sediments^ 
568 
Hsematogen,  411,  417 
Hsematoglobulin.    See  Oxyhaemoglobin. 
Haematolin,  144 

Heematoporphyrin,  relation  to  biliru- 
bin, 144,  245 
,  relation  to  urobi- 
lin, 501 
,  properties  of,  144 
,  occurrence    of,    in 
urine,   540 
in    lower    animals, 
578 
Hsematoporphyrinuria,  540 
Hsematuria,  538 
Hsemerythrin,  148 
Hsemin,  142,  143 

Hsemin  crystals,  142,  143,  144,  540 
Hsemochromogen,  131 

,  properties  of,  140 
,  occurrence  in  mus- 
cle, 365 
Hsemocyanin,  148 
Haemoglobin,  43,  135 

,  properties  and  behavior, 

135 
,  quantity  in  blood,  130, 

131,  169—174 
,  quantitative   estimation, 

148 
,  behavior   in  trypsin  di- 
gestion, 308 
See  also  Oxyhaemoglobin 
and  the  combinations 
of    haemoglobin    with 
other  gases. 
Hsemoglobinuria,  538 
Hsemometer,  148 
Hsemosiderin,  246 
Haeser's  coeflBcient,  521 


Hair,  49,  573 
Hair-ash,  573 
Hair-balls,  325 
Hair-pigments,  576,  577 
Half  rotation,  64 
Haptogen-membrane,  423 
Heat,  action  on  metabolism,  645,  646, 
650,  651 
of    combustion     of    food-stuffs, 
617—619 
,  loss   of,  by  the  skin,   582,   620, 
645,   646 
Heat  development  in  plants,  2 
Helicoproteid,  18,  47 
Heller's  albumin  test,  26 

albumin  test  for  urine,  532. 
Heller-Teichmann's  blood  test,  539 
Hemialbumose,  35 
Hemicelluloses,  80 
Hemicollin,  55 
Hemielastin,  52 
Hemipeptone,  35 
Hemp-seed  calculi,  570 
Hen's  egg,  410—418 

,  incubation     of,     418,     419 
Heteroalbumose,  35 
Heteroxanthin,   102 

in  urine,  484 
Hexobioses,  72 
High  elevations,  action  on  the  blood, 

600 
Hippomelanin,  576 
Hippuric  acid,  485 

,    properties    and    reac- 
tions, 487 
,   formation    in    the    or- 
ganism, 3,  436,  487, 
488,  527 
,  cleavage  of,  485,  489 
,  occurrence,  486 
,  occurrence    as    s  e  d  i  - 
ments,  568 
Histon,  101,  158,  162,  203 
Histozyme,  489 
Hofmann's  tyrosin  test,  305 
Holothuria,  mucin  of,  47 
Homocerebrin,  392,  394 
Homogentisic  acid,  493,  497,  498 


INDEX. 


683 


Hopkins's  method  for  the  estimation 

of  uric  acid,  481 
Hoppe-Seyler's    carbon-monoxide    test, 
139 
xanthin  test,  105 
Horn,  49,  573,  579 

Horn  substance  in  the  gizzard  of  birds, 
51 
See  also  Keratin. 
Huckleberries,  coloring  matter   of,  in 

urine,  530 
Humin  substances  in  urine,  499,  530 
Humor,  aqueous,  195 
Huppert's   reaction   for   bile-pigments, 
235 
reaction    for    bile-pigments 
in  urine,  543 
Hyalines,  47 

of    the    walls     of    hydatid 

cysts,  575 
of    Rovida's    substance,    91, 
129,  150,  199,  403 
Hyalogen,  47 
Hyalomucoid,  400 
Hyaloplasm,  90,  96 
Hydatid  cysts,  575 
Hydracrylic  acid,  371 
Hydrsemia,  173 
Hydramnion,  419 
Hydrazone,  62 
Hydrobilirubin,   234 

,   relation    to    urobilin, 

245,  317,  501 
,    formation    in    putre- 
faction, 317 
Hydrocele  fluids,  194 
Hydrocinnamic  acid,  behavior  in  the 

body,  486 
Hydrochinon,  493,  530 
Hydrochinon-sulphuric   acid,   489,   491 
Hydrochloric  acid,  secretion  of,  in  the 
stomach,  263, 274, 
277,  283 
,  anti-feimentive  ac- 
tion of,  282 
,   action    on   the    se- 
cretion    of    pep- 
sin, 262 


Hydrochloric  acid,    action  on  the  py- 
lorus, 279 
,   quantity     in     gas- 
tric  juice,   264 
,    quantitative    esti- 
mation   in    gas- 
tric      contents, 
286 
,  reagents    for    free, 

285,  286 
,   action   on   proteid, 
21,    27,    32,    268, 
272 
Hydrogen  in  putrefactive  and  fermen- 

tive  processes,  5,  314,  316 
Hydrogen  peroxide  in  urine,  519 

,   decomposition   of, 
by   enzymes,   12 
Hydrolytic      splittings,      in      general, 
9,  10.     See    also    the    various    split- 
tings. 
Hydronephrosis  fluid,  446 
Hydroparacumaric    acid    in    putrefac- 
tion in  the  intestine,  305,  314 
Hydrophenoketon,   7 
Hydrocyanic    acid,    action    on    pepsin 
digestion,     270 
,    action  on  trypsin, 
digestion,    301 
Hyoglycocholic  acid,  227 
Hypalbuminosis,   175 
Hyperalbuminosis,  175 
Hyperglycaemia,   220 
Hyperinosis,   175 
Hypinosis,   175 

Hypnotics,    relation    to    glycogen   for- 
mation,  214 
Hyposulphurous    acid    in    the    urine, 

508,  524 
Hypoxanthin,    relation      to      uric-acid 
formation,   475 
,     properties,  106 
,    quantity    in    the    liver, 

208 
,    quantity   in    the   mus- 
cles,   366 
,    quantity    in    the    pan- 
creas, 292 


684 


INDEX. 


Hypoxanthin,    quantity      in      the 
sperma  (seeSarkin), 
406 
,    transition     into     the 
urine,  484 

lehthidin,  411,  417 
Ichthin,  417 

Ichthulin,  18,  47,  411,  417 
Icterus,  222,  246,  247 
,  blood,  176 
,  urine,  502,  542 
Immunity  against  infection,  16 
Indican,   urine,   493 — 495 

,    elimination     in     starvation, 

317,   494 
,   elimination   in   diseases,   494 
Indican  test,  Jaflfe's,  495 

,   Obermayer's,   495 
Indigo,  493 

in   the   sweat,   581 
Indigo  blue,  495,  500 
Indol,  properties,  314,  315 

,  formation  from  proteids,  22 
,  formation  in  putrefaction,  314, 
317,   489,  494 
Indophenol  blue,  behavior  in  the  tis- 
sues, 5 
Indoxyl,  489,  494 

Indoxyl-glycuronie  acid,  493,  495,  529 
Indoxyl  red,  495 

Indoxyl-sulphuric   acid,   489,  493—495 
Inosinic  acid,  366 

Inosit,  properties  and  occurrence,  369 
in  urine,  565 
,  relation    to    the    formation    of 
glycogen,  214 
Internal  respiration,  583,  593 
Intestine,    putrefaction    processes    in, 
313—320 
,    absorption     in,     318,     320, 

327—341 
,    digestion  processes  in,  309 
—314 
Intestinal  calculi,  325 
Intestinal  contents,  309 — 325 
Intestinal  fistula,  289 
Intestinal  gases,  314,  316 


Intestinal  juice,  289—291 
Intestinal  mucous  membrane,  289 
Intracellular  action  of  enzymes,  11,  73 
Inulin,   71,   76 

as  a  glycogen-former,  214 
Inversion,  10,  73,  272,  290,  309,  332 
Invertin,  74,  257,  297 
Invert-sugar,    10,   73 
Iodine  combinations,  passage  of,  into 
the  milk,  443 
,  passage  of,  into 
the     sweat, 
581 
,  passage  of,  into 
the       saliva, 
260 
Iodoform  test.  Gunning's,  558 

,  Liebei's,  558 
Iron  in  the  blood,  125,  167,  168 

in  the  blood-pigments,   131,   141, 

143,  146,  245,  246 
in  the  bile,  238,  241 
in  the  urine,  519 
in  the  liver,   183,   184,  238,   245, 

246 
in  the  milk,  433,  437,  443 
in  the  spleen,  201,  202 
in  the  muscles,  374 
in  new-born,  201,  210,  440 
in  protein  substances,  17,  19,  31, 

32,  98,  99,  201,  207 
in  cells,  109,  110 
,  elimination  of,  238,  245,  246,  519 
,  quantity  of,  in  bitch's  milk  and 

new-born   dogs,   440 
,  absorption  of,  173,  629 
,  grains  rich  in,  of  the  spleen,  201 
Iron  salts,   elimination  by   the  urine, 
519 
,    action  on  the  blood,  173 
,    action    on    trypsin    diges- 
tion, 301 
,    action  on  absorption,  173, 
629 
Iron  starvation,  629 
Ischuria  in  cholera,  581 
Isocholesterin,   250 
Isodynamic  law,  618,  619 


INDEX. 


685 


Isoglucosamin,  63 

Isomaltose,  72,  74,  78,  256,  297 

in  urine,  505 
Isosaccharin,     relation      to     glycogen 

formation^    214 
Isotonic  relationship,  164 
Isotropous  substance,  361 
Ivory,  354 

Jaffe's  indican  ttst,  495 

creatinin   reaction,  469 
Janthinin,    578 

Japanese,  nourishment  of,  653,  654 
Jaune   indien,   506 
Jecorin,  95,   123,  201 

,  properties  and  occurrence,  208 
Jequirity  bean,  15 
Jolles's  reaction  for  bile-pigments,  543 

Kairin,  action  on  the  urine,  530 
Kephalines,  391 
Kephir,  434 

,  preventive    action    on    putre- 
faction, 318 
Kerasin,  392 
Keratins,  18,  49,  573 

,  properties  of,  49,  50 

,  behavior  with  gastric  juice, 

271 
,  behavior      with     pancreatic 
juice,  308 
Keratinose,  50 
Ketoses,  60,  63 
Kidneys,  446 

,  relation  to  formation  of  uric 

acid,  476 
,  relation      to      formation      of 

urea,  457 
,  relation  to  formation  ox  hip- 
puric  Acid,  487 
Kjeldahl's  method  of  determining  ni- 
trogen, 461,  466 
Knapp's  titration  method,  552 
Knop-Hiifner's    method    for   determin- 
ing urea,  466 
Kumyss,  434 
Kyestein,  568 
Kynurenic  acid,  497,  509 


Laborer,  diet,  653—658 
Lactalbumin,   18,  428 
Lactates,  373 
Lactic  acids,  371 

in  the  intestine,  313 
in  the  urine,  380,  505 
in  the  bones,  352 
in      the      gastric      juice, 
264 
,  relation  to  the  formation 
of  uric  acid,  475 
See   also    Paralactic    and 
Fermentation    lactic 
acid. 
Lactic-acid  fermentation,  69,  27  <,  283, 
332,      371, 
422,  429 
•  in  intestine, 

309,  371 
in  urine,  564 
in  stomach, 

277,  283 
in  milk,  422, 
429 
Lacto-caramel,  428 
Lacto-globulin,  428 
Lacto-protein,  428 
Lactose.     See  Milk-sugar. 
Leevo-lactic  acid,  371 
Laiose,  555 
Lanolin,  250,  579 
Lard,  absorption  of,  336 
Latebra,  410 
Laurie  acid  in  butter,  424 

in  spermaceti,  86 
Laxatives,  action  on  the  blood,  175 

,  action  on  the  secretion  of 

intestinal   juice,   289 
,  action  of,  324 
Lead  in  blood,  168 

in  the  liver,  210 
,  passage  of,  into  milk,  443 
Lecithalbumins,  31 

,  relation  to  tlie  secre- 
tion of  gastric  juice, 
274 
,  relation  to  the  secre- 
tion of  urine,  446 


686 


INDEX. 


Lecithin,   properties,    occurrence,    etc., 
93 
,    action    on    the    coagulation 

of  blood,  160 
,    putrefaction  of,  94,  317 
,    behavior  in  muscular  activ- 
ity, 381 
Legal's  reaction  for  acetone,  558 
Legumin  from  peas,  42 
Lens  (see  Crystalline  lens),  400 
,  capsule  of  the,  47,  400 
,  fibres  of,  401 
Leo's  method  for  the  determination  of 
acidity,  288 
sugar,  555 
Lethal,  86 
Leucaemia,  blood  in,  103,  174 

,  secretion  of  uric  acid,  202, 

474,  476 
,  xanthin  bases  in,  103,  174, 
202,  483 
Leuceine,  20 
Leucin,  20,  21,  50—57,  302 

,   relation   to   the   formation   of 

uric  acid,  475 
,   relation   to   the   formation   of 

urea,  455,  523 
,  preparation  of,  305 
,  properties  of,  302—304 
,  transition  into  the  urine,  562 
,   behavior  in  the  body,  455,  523 
Leueinic  acid,  303 
Leucinimid,  24 

Leucocytes,  relation  to  absorption,  330 
,  relation    to    formation    of 
uric  acid,  475 
in  the  thymus  gland,  91, 

92 
See  also  the  white  blood- 
corpuscles. 
Leucomaines,   15 

in  urine,  509 
in  muscles,  369 
Leuconuclein,  159,  162,  203 
Levulose,  relation  to  the  formation  of 
glycogen,    216,    221 
,  absorption  of,  332 
,  behavior  in  diabetics,  221 


Levulose,  occurrence  in  urine,  554 

See  also  Fructose. 
Levulinic  acid,  66,  428 
Lichenin,   77 
Lieberkiihn's  alkali-albuminate,  32 

glands,   289 
Lieberman's  reaction  for  proteids,  27 
LieDermann-Burchard's  cholesterin  re- 
action, 249 
Liebig's     titration    method  for     urea, 

461 
Ligamentum  nuchse,  51 
Lignin,  79 

Linseed  oil,  feeding  with,  355 
Lion's  urine,  471 
Lipaemia,  175 
Lipacidsemia,   175 
Lipanin,  absorption  of,  335 
Lipochromes,  125,  412 
Lipuria,  562 
Lithobilic  acid,  326 
Lithofellic   acid,   326 
Lithium  in  the  blood,  168 
Lithium  lactate,  374 
Lithium  urate,  478 
Lithuric  acid,  509 
Liver,  206—210 

,  relation    to    the    formation    of 

uric  acid,  475 — 477 
,  relation    to    the    formation    of 

urea,  455,  457,  458 
,  blood  of  the,  169,  206,  217 
,  proteids  in,  207 
,  fat  in,  207,  208 
,  amount  of  sugar  in,  217 
,  atrophy  of,  acute  yellow,  458 
,  atrophy  of,  elimination  of  am- 
monia in,  458 
,  atrophy  of,  elimination  of  urea 

in,  458 
,  atrophy  of,  elimination  of  leu- 
cin and  tyrosin  in,  562 
,  atrophy  of,  elimination  of  lac- 
tic acid  in,  372,  505 
,  extirpation    of,    elimination    of 

ammonia,  457,  474 
,  extirpation    of,    elimination    of 
uric  acid,  474 


INDEX. 


esr 


Liver,  extirpation    of,    elimination    of 
lactic  acids,  372,  474,  505 
,  extirpation    of,    action    on    the 

formation  of  bile,  242,  244 
,  cirrhosis    of,    ascitic    fluid    in, 

193,  194 
,  cirrhosis     of,     action     on     the 
elimination  of  ammonia   and 
urea,  458 
Lungs,  605 

,  catheter  for,  595 
Lutein,  412 

in  corpora  lutea,  406,  412 
in  yolk  of  the  egg,  412 
in  serum,   125 

relation    to    haematoidin,    145 
406 
Lymph,   180—188 
Lymphagogues,  180,  185—188 
Lymphatic  glands,  200 
Lymph-cells,      quantitative      composi- 
tion of,  203 
See   also   White   blood- 
corpuscles. 
Lymph-fibrinogen.     See  Tissue-fibrino- 

gen. 
Lysatin,  21,  454 

Lysatinin,  21,  50,  52,  54,  56,  302,  313 
Lysin  21,  50,  52,  54,  56,  302,  313,  454 

Mackerel,  flesh  of,  387 
Madder,  feeding  with,  351 
Magnesium  in  urine,  513,  519,  522 
in  bones,  349 
in  muscles,  374,  386 
See   also   the   various   tis- 
sues and  fluids. 
Magnesium    phosphate     in     intestinnl 
calculi,  325 
in   urine,  513, 

519 
i  n       urinary 
calculi,  569, 
570 
in        urinary 
sediments, 
568 
in  bones,  349 


Magnesium  soaps  in  excrements,  322 

Malaria,  176 

Malerba's  acetone  reaction,  559 

Malt  diastase,  257 

Maltodextrin,  78 

Maltose,  74 

,  relation    to    starch,    78,    256, 

297 
,  absorption  of,  332 
,  relation    to    glycogen    forma- 
tion, 216 
,  relation    to    intestinal    juice, 
257,  309,  332 
Mammary  glands,  420,  441,  443 
Man  in  poorhouse  diet,  657 
Mandelic  acid,  527 
Mannite,  61,  67 

,   relation  to  glycogen  forma- 
tion, 214 
Mannose,  67,  71 
Mannoso-cellulose,  80 
Mare's  milk,  434 
Margarine  and  margaric  acid.  84 
Marsh-gas  in  intestine,  314,  317 

in  putrefaction,  22,314,317 
in    fermentation    of    cellu- 
lose, 317 
in    the     decomposition     of 
lecithin,  94,  317 
Meat,    consumation    of,    in    intestinal 
canal,  330 
,    caloric  value,  617,  618 
,    digestibility,  279.  280 
,    composition,     356,     357,     386— 
388 
See  muscles  in  general. 
Meconium,  323 
Melanaemia,  176 

Melanins,   relation   to  blood-pigments, 
246 
,  properties    and    occurrence, 
576—578 
in  the  eye,  400 
in  the  urine,  541 
Melanogen  in  the  urine,  541 
Melanotic  sarcoma,  pigments  of,  576, 

577 
Melebiose,  75 


688 


INDEX. 


Mellitsemia,  176 

Melissyl  alcohol,  87 

Membranin,  47,  348,  400 

Menstrual  blood,  170 

Menthol,    behavior    in    animal    body, 

529 
Mercapturic  acids,  529 
Mercury  salts,  passage  of,  into  milk, 
443 
,  passage  of,  into  sweat, 

581 
,  action  on  ptyalin,  258 
,  action  on  trypsin,  301 
Mesitylen,  behavior   in   animal   body, 

527 
Mesitylenic  acid,  527 
Mesitylenuric  acid,  528 
Metabolism,    dependence    upon    exter- 
nal   temperature,   422, 
650 
in  various  ages,  645,  646 
in  work  and  rest,  377 — 

385,  648 
in    the    different    sexes, 

645 
in    starvation,    619 — 625 
with  different  foods,  630 

—642 
in    sleep    and    awaking, 
650 
,    calculation  of  the  extent 
of,  612—616,  624 
Metalbumin,  407,  408 
Metaphosphoric    acid,    constituent    of 
nucleins,    98 
,    as  reagent  for 
proteids,    26, 
533 
Methsemoglobin,  136 

in  blood  after  poison- 
ing, 177 
in  urine,  538 
Methal,  86 
Methane,    formation    in    putrefaction, 

22,  314,  317 
Methylenitan,  67 
Methyl  glycocoll.     See  Sarcosin. 
Methyl  guanidin,  367,  469 


Methyl-guanidin-acetic      acid.         See 

Creatin. 
Methyl-hydandoinie  acid,  523 
Methyl  hydantoin,  471 
Methyl  indol.     See  Skatol. 
Methyl    mercaptan   in   proteid    putre- 
faction, 22,  314, 
316 
in  urine,  530 
Methyl   pyridin,   behavior   in   the   or- 
ganism, 530 
Methyl-pyridyl-ammonium   hydroxide, 

530 
Methyluramin,  367,  469 
Methyl-uric  acid,  471 
Microorganisms     in     intestinal    tract,, 

13,  282,  313,  321 
Micrococcus  restituens,  329 
Micrococcus  ureee,  565 
Milk,  420—444 

,  secretion  of,  441 — 443 

,  consumation    of,    in    intestine,. 

330,  337,  338 
,  blue  or  red,  444 
,  anti-putrefactive     action,     318, 
490 
in  disease,  443 
,  passage  of  foreign  bodies  into,, 

443 
,  behavior   in    the    stomach,    276, 
281,  436 
See  also  the  different  varieties 
of  milk. 
,  human,  435—439 
,  human,    behavior    in    stomach,, 

276,  436 
,  human,  composition  of,  436, 437 
of  blondes,  439 
of  brunettes,  439 
Milk-fat,  424,  434,  435 

,  analysis  of,  424 
,  formation,  442 
Milk-globules  of  cow's  milk,  422,  423 

of  human  milk,  435 
Milk-plasma,  424 
Milk-sugar,  73,  428 

,  relation   to   glycogen   for- 
mation, 216 


INDEX. 


689 


Milk-sugar,  properties,  428,  429 

,  fermentation,      277,      422, 

429 
,  inversion,  290,  332,  429 
,  caloric  value,  617 
,  quantitative      estimation, 

432 
,  absorption,  332 
,  passage  of,  into  the  urine, 

429,  555 
,  origin,  420,  442 
Millon's  reagent,  27 
Mineral  acids,  alkali-removing  action, 
448,  517,  590,  626 
,  anti-fermentive    action, 

282 
J  action  on  the  elimina- 
tion     of      ammonia, 
517,  628 
Mineral  bodies  eliminated  in   starva- 
tion, 623 
,  insufficient  supply  of, 

625 
,  behavior    in    the    or- 
ganism,   626 
See  the  various  fluids, 
tissues,  and    juices. 
Mitoplasm,  96 
Mixture  of  the  nitrogenous  substances 

in  the  urine,  454,  473,  474 
Modified  proteid  bodies,  30 
Mohr's  titration  method  for  estimat- 
ing chlorine,  510 
Monosaccharides,  60 
Morner  and  Sjoqvist's  method  of  esti- 
mating urea, 
466 
method  of  esti- 
mating acids, 
286 
Moore's  test  for  sugar,  68 
Morphin,   passage   of,   into   the   urine, 
530 
,  passage   of,   into   the   milk, 
443 
Mucic  acid,  77,  428 

,  relation  to  glycogen  for- 
mation, 214 


Mucilages,  vegetable,  77,  79 
Mucin,  18,  45 

in  sputum,  606 
in  connective  tissue,  342 
in  urine,  509,  537 
in  salivary  glands,  44,  252 
,  detection  of,  in  the  urine,  537 
Mucin-like  substances  in  bile,  225 

in    urine,    509, 

537 
in  the  kidneys, 

446 
in  the   thyroid 

gland,   204 
in  the  synovial 
fluid,    196 
Mucoids,  18,  47 

in  ascitic  fluids,  191,  193 
in  the  vitreous  humor,  343> 

400 
in  the  cornea,  348 
Mucinogen,  44,  252 
Mucin  peptone,  271 
Mucous  glands,  44,  251 
Mucous    membranes    of   the   stomach, 

261 
Mucous  tissue,  343 
Mucus  of  the  bile,  224,  225 

of  the  urine,  447,  509,  532,  537 
of  the  synovial  fluid,  196 
Mulberry  calculus,  570 
Murexide  test,  478 
Muscles,  striated,  360 — 388 
,  non-striated,  388 
,  blood    of   the,    170,   378,   384, 

584 
,  chemical    processes    in    work 
and  at  rest,  377 — 385 
in  rigor,  375 — 377 
,  proteids  of,  361—366 
,  extractives  of,  366 — 375 
,  pigments  of,  365 
,  fat  of,  374,  383,  386,  387 
,  gases  of,  375,  377,  384 
,  caloric  value  of,  617 
,  mineral  bodies,  374,  386 
,  quantity  of  water,  387 
,  composition  of,  386 


690 


INDEX. 


Muscle-fibres,  360 
Muscle-pigments,  365 
Muscle-plasma,  361,  362 

,  coagulation     of,     362, 
363,  376,  388 
Muscle-serum,  362 
Muscle-stroma,  365 
Muscle-sugar,  371 
Muscle-syntonin,  365 
Muscular  energy,  origin  of,  384 
Muscular  work,  chemical  processes  in 
the  muscles,  377 — 
385 
,  influence       on       the 
urine,      448,      468, 
471,  508 
,  influence  on  metabo- 
lism, 377—385 
Musculin,  18,  364 
Mussels,  glycogen  of,  210 
Mustard-seed  oil,  action  on  the  secre- 
tion of  pancreatic  juice,  296 
Mutton-fat,  feeding  with,  355 

,  absorption  of,  335,  336 
Myco-protein,  19 
Myeline,  391 
Myeline  forms,  94,  391 
Mygge    and    Christensen's    estimation 

of  proteid,  537 
Myoalbumose,  364 
Myoalbumin,  364 
Myoglobulin,  364 
Myohsematin,  365 
Myosin,  362 

in  leucocytes,  150 
Myosinogen,  363 
Myosin  ferment,  363 
Myosinoses,  36 
Myricin,  87 
Myricyl  alcohol,  87 
Myristic  acid  in  butter,  424,  435 

in  the  bile,  238 
Myxoedema,  204,  343 

Nails,  49,  573 

Naphthalin,  action  on  the  urine,  530 
,  behavior    in    the    animal 
body,  526 


Naphthol,  reagent     for     sugar,      70, 
549 
,  behavior     in     the     animal 
body,  529,  530 
Naphthol-glycuronic  acid,  529,  530 
Narcotics,  relation  to  glycogen  forma- 
tion, 214 
Native  proteids,  29 
Navel  cord,  mucin  of,  46,  343 
Neossin,  47 
Nerves,  390,  397 
Neuridin,  392,  395,  410 
Neurin,  93 

in  suprarenal  capsule,  205 
in  protagon,  392 
Neurochitin,  397 
Neurokeratin,  49,  390,  397 
Neutral  fats.      See  Fats. 
Nicotin,  action  on  quantity  of  CO     in 

the  stomach,  278 
Nitrates  in  the  urine,  517 
Nitric-oxide  hsemoglobin,  140 
Nitrogen,  free,  in  blood,  584 

,  free,  in  intestine,  316 
,  free,  in  stomach,  278 
,  free,  in  secretions,  591 
,  free,   in   transudations,   592 
,  combined,    quantity    of,    in 
the      intestinal      evacua- 
tions, 610,  611 
,  combined,    quantity    of,    in 

meat,  388,  613 
,  combined,    quantity    of,    in 

the  urine,  454 
,  estimation  of,  in  the  urine, 
461,  465 
elimination    in    work    and 

rest,  381—384,  647,  648 
elimination    in    starvation, 

620—622 
elimination    with    different 

foods,   630—642 
elimination     by     intestinal 

evacuations,  610,  611 
elimination    by    the    urine, 

454,  513,  515,  610,  612 
elimination     by     the     epi- 
dermis, 611 


INDEX. 


G91 


Nitrogen    elimination    by    the    sweat, 
581,  Gil 
elimination,  relationship  to 
the   elimination   of   phos- 
phoric acid,  513 
elimination,  relationship  to 
the    elimination    of    sul- 
phuric acid,  515 
in  meat,  388 
Nitrogenous  equilibrium.  G12 
Nitrogenous    equilibrium    with   differ- 
ent foods,  630—642 
Nitrogenous  deficit,  611 
Nitro-benzaldehyde,    behavior    in    the 

animal  body,  528 
Nitro-benzoic  acid,  24,  528 
Nitro-benzyl  alcohol,  529 
Nitro-cellulose,  79 
Nitro-hippuric  acid,  528 
Nitroso-indol  nitrate,  315 
Nitro-phenyl-propiolic     acid,     reagent 

for  sugar,  70 
Nitro-phenyl-propiolic    acid,    behavior 

in  the  body,  494,  495 
Nitro-toluol,   behavior   in   the   animal 

body,  529 
Nitro-tyrosin  nitrate,  305 
Nubecula,  447,  564 
Nucleic  acid,  48,  91,  96,  97,  99,  100 

,  combination  with  haemo- 
globin, 131 
,  combination    with     pro- 
tamin,  405 
Nuclein  bases,  98,  103 

in  sperma,  405,  406 
Nucleins,  48,  91,  96,  97,  98 

,  relation     to     formation     of 
uric  acid,  475 
Nuclein  plates,  151 
Nucleo-albumins,   18,  31 

in  the  bile,  225 

in    the    urine,    509, 

537 
in  the  kidneys,  446 
in     protoplasm,    31, 

91 
in  the  synovial  fluid, 
196 


Nucleo-albumins      in      transudations, 
189,   190,   192 
,     behavior  to  pepsin, 
digestion,  31,  270, 
427 
Nucleo-histon,  18,  92,  101 

,  relation   to   the   coagu- 
lation  of   blood,    158, 
159 
Nucleo-proteids,  18,  31,  43,  48 

in     the     mammary 

glands,  420 
in    the    pancreas,    48, 

292 
in  protoplasm,  91 
in    the    cell    nucleus, 
96,  101 
,  behavior     to     pepsin 
digestion,    48,     101, 
270 
Nutrition  requirements,  633 

of    man,    652 
—659 
Nylander's  reagent.     See  Almen-Bott- 
ger's  sugar  test. 

Obermayer's  indican  test,  495 

Obermiiller's  cholesterin  reaction,  250 

Odoriferous  bodies  in  the  urine,  530 

ffidema,  subcutaneous,  fluid  from,  196 

Oertel's  cure  for  corpulency,  658,  659 

Oleic  acid,  81,  84 

Olein,  81,  84 

Oligaemia,  173 

Oligocythsemia,   173 

Oliguria,  522 

Olive  oil,  absorption  of,  335 

,  action   on   the   secretion   of 
bile,  223 
Onuphin,  47 
Oocyanin,  416 
Oorodein,  416 

Opium,  passage  of,  into  milk,  443 
Optograms,  399 
Organic  acids,  behavior  in  the  animal 

body,  505,  518.  523 
Organized  proteids,  633,  634 
Organs    of  generation,  403 — 419 


692 


INDEX. 


Organs,  loss  of  weight  in  starvation, 

623 
Ornithin,  21,  524,  527 
Orthonitro-phenyl-propiolic  acid.      See 

Nitro-phenyl-propiolic  acid. 
Osazones,  62 

Osmosis,  relation  to  absorption,  340 
Osone,  62 
Ossein,  348,  352 
Osteomalacia,  352,  353 

,  lactic  acid  in  the  urine 
in,  372 
Osteoporosis.     See  Osteosclerosis. 
Osteosclerosis,  352 
Otoliths,  402 
Ovalbumin,  18,  414 

,  behavior    in    the    animal 
body,  121,  415 
Ovarial  cysts,  406 — 410 
Ovaries,  406 
Ovglobulin,  414 
Ovomucoid,  415 — 418 
Ovovitellin,  18,  410 
Oxalate  of  lime.    See  Calcium  oxalate. 
Oxalate  calculi,  570 
Oxalates,  action  on  blood  coagulation, 

112 
Oxalic  acid  in  the  blood,  176 

in  the  urine,  481,  482 
,  behavior    in    the    animal 
body,  481,  523 
Oxalic-acid  diathesis,  482 
Oxaluria,  482 
Oxaluric  acid,  472,  481 
Oxamid,  20 

Oxidations,    1—9,    134,   221,   234,   314, 
454,  456,  474,  489,  494,  499,  523,  525, 
526,  529,  585 
Oxidation  ferment,  8 
Oxyacids,    formation    in    putrefaction, 
314 
,   passage  of,  into  the  urine, 

314,  497 
,   passage  of,  into  the  sweat, 
581 
Oxybenzols,  526 

Oxybenzoic  acid,  behavior  in  the  ani- 
mal body,  527,  528 


Oxybutyric  acid  in  the  blood,  590 

,  passage  of,  into  the 
urine,   518,   560 
Oxygen  absorption  in  work  and  rest, 
378,   384 
in  starvation,  622, 

624 
by  the  skin,  582 
Oxygen,  activity  of,  4,  7,  134,  585 

in   the   blood,   584,   585,   594, 

596,  597,  599 
in  the  intestine,  316 
in  the  lymph,  182,  590 
in  the  stomach,  278 
in   the   swimming-bladder   of 

fishes,   603 
in  secretions,  590 — 592 
in  transudations,  592 
,  combination  of,  in  the  blood, 

132,  133,  585,  593,  597 
,  tension  of,  in  the  blood,  593 

—597 
,  tension  of,  in  the  expired  air, 

594,  595 
,  action  of  CO     on  the  tension 

of,  600,  601,  602 
,  lack    of,    action    on    proteid 

destruction,  372,  453 
,  lack    of,    action    on    elimina- 
tion of  lactic  acid,  372,  505 
,  lack    of,    action    on    elimina- 
tion of  sugar,  372,  505 
,  specific  quantity,  597 
Oxygen  carriers,  8,  134 
Oxygen    consumption    in    the    blood, 

136,  585 
Oxyhsematin,  141 
Oxyhsemocyanin,  148 
Oxyhaemoglobin,  132 

,  dissociation   of,    132, 

593 
,  properties   and   reac- 
tions, 133,  134 
,  quantity   of,    in    the 
blood,      130,      131, 
169—174 
,  quantity   of,    in   the 
muscles,  365 


INDEX. 


693 


Oxyhaemoglobin,  passage   of,   into   the 
urine,   538 
,  behavior    with    gas- 
tric juice,  272 
,  behavior   with   tryp- 
sin, 308 

Oxyhydro-paracumaric  acid,  497 

Oxynaphthalin,  52G 

Oxynitro-albumin,   24 

Oxyphenyl-acetic  acid,  305,  314,  497 

Oxyphenyl-amido-propionic   acid.     See 
Tyrosin. 

Oxyphenyl-propionic  acid,  22,  314,  497 

Oxyproto-sulphonic  acid,  24 

Ozone,  3,  585 

Ozone  exciter,  134,  585 

Ozone  transmitter,  134 

Palmitic  acid,  84 
Palmitic-acid  ether,  87 
Palmitin,  83 
Pancreas,  291,  292 

,  relation  to  glycolysis,   123, 
294 
extirpation,    action    on    ab- 
sorption. 331,  332,  334 
extirpation,  action  on  elimi- 
nation of  sugar,  221,  292 
,  charge  of,  202 
,  change      during      secretion, 
292,  308 
Pancreas  proteid,  48 
Pancreas  rennin,  307 
Pancreatic  juice,  294 

,  secretion,    295,    296, 

308,  309 
,  enzymes   of,    12,   297 

—302 
,  action  on  foods,  297 
—302,      307,      311 
312,  331,  332,  337, 
338 
Paracasein,  427 
Parabanic  acid,  103,  472 
Paracresol,    formation    in   proteid   pu- 
trefaction, 314 
Paraglobulin.     See  Serglobulin. 
Parahaemoglobin,  134 


Paralactic  acid,  371,  372 

in  blood,  125,  168 
,  relation  to  the  forma- 
tion   of    uric    acid, 
475 
,  properties   and  occur- 
rence, 371 
,  formation    from    gly- 
cogen, 373—377 
in  osteomalacia,  352 
,  production  of,  in 
muscles   during   ac- 
tivity, 380,  384 
,  production  of,  in 
rigor     mortis,     375, 
376 
in   deficiency   of  oxy- 
gen, 372,  380,  505 
in    animals    with    ex- 
tirpated livers,  372, 
505 
,  passage    of,    into    the 
urine,  475,  505 
Paralbumin,  407,  409 
Paramidophenol,    526 
Paramucin,   409 
Paramyosinogen,  362,  364 
Paranuclein,  31,  97 
Paranucleon,   369 
Parapeptone,  271 
Para-oxyphenyl-acetic    acid,    305,    314, 

497 
Para-oxyphenyl-propionic      acid,      22, 

314,  497 
Paraxanthin,   102,  484 

in  the  ui'ine,  484 
Parietal  or  delomorphic  cells,  261,  273, 

275 
Parotid,  251 
Parotid  saliva,  254 
Parovarial  cysts,  410 
Peas,  absorption  of,  in  the  intestine, 

334 
Pemphigus  chronicus,  196 
Penicillum  glaucum,  303 
Pentacrinin,  578 
Pentamethylendiamin.       See      Cadar- 


694 


INDEX. 


Pentosanes,  65 
Pentoses,  65,  77 

J  relation  to  glycogen  forma- 
tion, 213 
in  the  urine,  65 
in  the  pancreas,  65,  555 
Pentosuria,  556 
Pepsin,  264,  265—267 
,  properties,  266 
,  detection   in  the  gastric   con- 
tents, 283 
,  quantitative     estimation      of, 

268 
,  occurrence  in  the  urine,  339, 

508 
,  occurrence  in  the  muscles,  366 
,  action  on  proteid,  267 
,  action    on    other    bodies,    271, 
272 
Pepsin  digestion,  267,  269—272,  279 

,  products   of,   33,   34, 
41,  270,  271,  272 
Pepsin  glands,  261 
Pepsin-hydrochloric  acid,  272 
Pepsinogen,  261,  275 
Pepsin  test,  268 
Peptochondrin,  346 
Peptones,  33—42 

in  putrefaction,  21,  314 
in  pepsin  digestion,  33 — 41, 

271 
in    trypsin    digestion,    33 — 
41,  302 
,  assimilation  of,  327 — 330 
,  relation  to  amylolysis,  258 
,  preparation  of,  40 
,  nutritive  value  of,  330,  636 
,  absorption  of,  327—330 
,  passage  into  the  urine,  327, 
535 
Peptone-plasma,  111,  156,  160 

,  carbon- dioxide      ten- 
sion, 602 
Peptonuria,  534 
Pericardial  fluid,  189,  191 
Perilymph,  402 
Period  of  incubation,  418 
Peritoneal  fluid,  189,  193 


Perspiratio  insensibilis,  609 
Pettenkofer's  test  for  bile-acids,  226 

respiration       apparatus,, 
604 
Phacozymase,  401 
Phaseomannit,  369 
Phenaceturic  acid,  488,  527 
Phenols,  elimination  by  the  urine,  489 
—493,   529 
in  starvation,  317 
,  estimation  in  the  urine,  490 

—492 
,  action  on  the  urine,  493,  530 
,  electrolysis  of,  6,  525 
,  formation  in  putrefaction,  22, 

314,  489,  490,  529 
,  behavior  in  the  animal  body, 
314,   489 
Phenol-glycuronic  acid,  491,  529 
Phenol- sulphuric    acid    in    the    urine,. 
489   —   492, 
529 
in    the    sweat, 
581 
Phenyl-acetic   acid,   formation   in   pu- 
trefaction,     22, 
314 
,  behavior     in     the 
body,   488,    526, 
527 
Phenyl-amido-acetic  acid,  behavior  in 

the  body,  527 
Phenyl-amido-propionic   acid,   23 
Phenyl-amido-propionic  acid,  behavior 

in  the  body,  526,  527 
Phenyl-glucosazone,  62,  70 
Phenyl-hydrazine  test,  70 

in    the    urine, 
507,  547 
Phenyl-lactosazone,  429 
Phenyl-propionic    acid,    formation    in 

putrefaction,  22,  23,  314,  486 
Phenyl-propionic  acid,  behavior  in  the 

body,  486,  527 
Philothion,  8 
Phlebin,    130 
Phlorhidzin,  219 
Phlorhidzin  diabetes,  219 


INDEX. 


69^ 


Phlorogiucin  as  reagent,  285 
Phosphocarnic  acid,  368 
Phosphates  in  the  urine,  512 — 515,531, 
566 — 568.       See     also     the     various 
phosphates. 
Phosphate  calculi,  517,  518 
Phosphate  diabetes,  514 
Phospho-glyco-proteid,  47 
Phosphoric    acid,    elimination    by    the 
urine,   512 — 515 
,  formation    in    mus- 
cular activity,  381 
,  physiological  impor- 
tance, 109 
Phosphorized     combinations     in     the 

urine,  508 
Phosphorus  poisoning,  action  on  elim- 
ination of  am- 
monia, 458 
,  action  on  elim- 
ination       o  f 
urea,    458 
,  action  on  elim- 
ination       o  f 
lactic       acid, 
505 
,  fatty  degenera- 
tion     caused 
by,  356 
,  change    in    the 
urine,        458, 
505,  562 
Phrenosin,  394 
Phthalic  acid,  behavior   in   the  body, 

526 
Phymatorusin,  576,  577 

in  the  urine,  541 
Physetoelic  acid,  87 
Phytovitellin,  42 
a-Picolin,     behavior     in     the     animal 

body,  530 
Picric  acid,  reagent  for  proteid,  27,  536 
,  reagent  for  creatinin,  469 
,  reagent  for  sugar,  70,  469 
Pigments  of  the  eye,  397 — 400 
of  the  blood,  130—149 
of  the  blood-serum,  125,  412 
of  the  corpora  lutea,  406 


Pigments  of  egg-shells,  416 

of  the  fat-cells,  354 

of   bile,   224,   233—239,   241, 

243 
of  the  urine,  499—504 
of  the  skin,  576 — 578 
of  the  lobster,  417,  578 
of  the  muscles,  365,  366 
of  lower  animals,  578 
of  bird-feathers,  577,  578 
of   medicinal    drugs    in    the 
urine,  530,  544 
Pig's  milk,  434 
Pike,  flesh  of,  388 

,  stomach  of,  267 
Pilocarpin,  action  on  secretion  of  in- 
testinal juice,  289 
,  action  on  CO     elimination 

2 

in  the  stomach,  278 
,  action  on  secretion  of  pan- 
creatic juice,  206 
,  action  on  the  sweat,  581 
,  action  on  the  saliva.  259 
,  action   on   the  elimination 
of  uric  acid,  473 
Piperazin,  solvent  for  uric  acid,  477 
Piqilre,  220 

Piria's  tyrosin  test,  305 
Placenta,  419 
Plants,     chemical     processes     in     the 

same,  1,  2 
Plasma.     See  Blood-plasma. 
Plasmoschisis,  156 
Plastin,  90,  96,  101 
Plattner's  crystallized  bile,  225 
Plethora  polycythsemia,  173 
Pleural  fluid,  189,  192 
Plexus  coeliacus,   relation  to  acetonu- 
ria,  557 
,  relation      to      sugar 
formation,  293 
Plums,  influence  on  the  elimination  of 

hippuric  acid,  486 
Poikilocytosis,  174 
Polaristrobometer,   29 
Polycythajmia,   173,   178 
Polysaccharides,  75 
Polyperythrin,  578 


696 


INDEX. 


Polyuria,  514,  522 
Pork-fat,  absorption  of,  335 
Portal-vein  blood,  169,  217,  328 
Potassium    combinations,    elimination 

in  fevers,  517 
Potassium    combinations,    elimination 

in  starvation,  517,  623 
Potassium    combinations,    elimination 

by  the  urine,  517,  623 
Potassium    combinations,    elimination 

by  the  saliva,  260 
Potassium    combinations,    division    in 
the      form      elements     and     fluids, 
109 
Potassium    chlorate,    poisoning    with, 

136,  177 
Potassium   phosphate   in  yolk   of   the 
egg,   413 
in   muscles,   375 
in  cells,  109 
Potassium  sulphocyanide  in  the  urine, 

507 
Potassium    sulphocyanide    in    the    sa- 
liva, 253,  254 
Potatoes,   consumation   of,   in  the   in- 
testine, 334 
Preglobulin,  91,  102,  157 
Preputial  secretion,  579 
Prisoners,  food-ration  for,  657 
Propepsin,  275 
Propyl  benzol,  behavior  in  the  body, 

526 
Propylen  glycol,  relation  to  glycogen 

formation,  214 
Prostatic  calculi,  406 
Prostatic  secretion,  403 
Prostetic  group,  48 
Protagon,  95,  199,  391,  392,  397 
Protamin,  405 
Proteid,  separation  from  fluids,  29 

,  approximate     estimation     in 

the  urine,  536 
,  circulating     and      organized, 

633 
,  action    on    glycogen    forma- 
tion, 214,  215,  216 
,  living  and  dead,  4 
,  detection  of,  26,  27 


Proteid,  detection    of,    in    the    urine, 
531—537 
,  quantitative     estimation     of, 

28 
,  quantitative     estimation     of, 

in  the  urine,  536—538 
,  quantitative     estimation     of, 

in  milk,  430—432 
,  absorption  of,  326—332 
,  passage    of,    into    the    urine, 

372,  531 
,  heat   of   combustion   of,   617, 

618 
,  digestibility  in  gastric  juice, 

269,  280—282 
,  digestibility      in      pancreatic 
juice,  301,  302 
Proteid  bodies,  in  general,  17 — 29 
,  poisonous,  15,  42 
,  summary    of    the    va- 
rious,  17,  29^3  , 
,  vegetable,  42 
See    also    the    various 
proteid     bodies      of 
the       tissues       and 
fluids. 
Proteid  fattening,  633 
Proteid  of  the  hen's  egg,  413 
Proteid  metabolism  in  work  and  rest, 
381—385,      647, 
648 
in  starvation,  620 

—621 
at     various     ages, 

647 
with       different 
food,      629—642 
Proteid  putrefaction,  13,  14,  22,  314— 

320,  486,  489—496 
Protein   substances,    17 — 58.     See   also 

Individual  protein  bodies. 
Protein  chromogen,  22,  302 
Proteoses,  33,  36.    See  also  Albumoses. 
Prothrombin,  116,  157,  159,  160 
Protic  acid,  366 
Protocatechuic   acid,   behavior   in   the 

body,  493 
Protogelatose,  55 


INDEX. 


697 


Protoplasm,  89 
Pseudohaemoglobin,  130,  136 
Pseudomucin,  47,  408 

in  ascitic  fluids,  193 
in  the  gall-bladder,  240 
Pseudonucleins,  31,  97 

from  casein,  427,  430 
from  vitellin,  411 
Pseudoxanthin,  369 
Psittacofulvin,  578 
Ptomaines,  13,  14,  22 

in  the  urine,  509,  563 
Ptyalin,  255 

,  behavior    with     hydrochloric 

acid,  257,  277,  309 
,  action  on  starch,  255—253 
Pulmotartaric  acid,  605 
Purple,  578 
Purple  cruorin,  135 
Pus,  95,  197—200 
,  blue,  200 
in  urine,  541 
Pus-cells,  198 
Pus-serum,   197 
Putrescin,  14 

in  intestine,  563 
in  the  urine,  509,  563 
Pyin,  192,  198,  200 
Pyinic  acid,  200 
Pyloric  glands,  261,  273 
Pyloric  secretion,  275 
Pyocyanin,  200 

in  sweat,  581 
Pyogenin,  199,  393 
Pyosin,  199,  393 
Pyoxanthose,  200 

Pyridin,  behavior  in  the  body,  530 
a-Pyridinic  acid,  530 
rr-Pyridin-carbonic  acid,  530 
Pyrocatechin,  493 

,  occurrence  in  urine,  493 
,  occurrence      in      supra- 
renal  capsule,  205 
,  occurrence  in  transuda- 
tions,  191,   195 
Pyroeatechin-sulphuric  acid,  489,  492 
Pyromucic  acid,  524 
Pyromucin-ornithuric  acid,  524 


Pyromucuric  acid,  524 

Quadriurates,  478,  565 
Quercit,    relation    to   glycogen    forma- 
tion, 214 
Quinic  acid,  behavior  in  animal  body, 

486 
Quinin,  passage  of,  into  urine,  530 
,  passage  of,  into  sweat,  581 
,  action  of,  on  the  elimination 

of  uric  acid,  473 
,  action  of,  on  the  spleen,  203 
Quotient,  respiratory,  384,  599 

Rachitis,  bones  in,  352,  353 
Raffinose,  75 

Rape-seed  oil,  feeding  with,  355 
Reduction   processes,    1,   2,   5,   7,   234, 

316,  358,  486,  500,  524 
Reducing  substances,  formation  in  pu- 
trefaction  and   fermentation,  5,  316 
Reducing    substances,    occurrence    in 

the  blood,  5,  123 
Reducing     substances,     occurrence     in 

the  intestine,  316,  500,  501 
Reducing    substances,     occurrence    in 

the  urine,  505 
Reducing     substances,     occurrence     in 

transudations,  191,  195 
Rennin,  13,  264,  272,  276,  426 

,  detection  of,  in  stomach  con- 
tents, 284 
,  detection  of,  in  pancreas,  307 
,  transition  into  the  urine,  508 
Rennin-cells,  261 
Rennin-glands,  261 
Rennin  zymogen,  261,  273,  276 
Reserve  cellulose,  71,  80 
Resin  acids,  transition  into  the  urine, 

530,  533 
Respiration,  external,   583,  593,  594 — 
603 
,  internal,   583,  603 
with     increased     air-prea- 

sure.  598 
with  diminished  air-pras- 
sure,  598 


698 


INDEX. 


Respiration.     See  also  Exchange  of  Gas 
under     various     condi- 
tions, 
in  the  hen's  egg,  418 
of  plants,  2 

See    Chapter    XVII,    on 
the    Chemistry    of    res- 
piration    and     on    Ex- 
change of  gas. 
Respiratory  quotient,  384,  599 
Rest,   metabolism    during,   377,   378 — 

385 
Reticulin,  18,  56,  342 
Retina,  398 
Reversion,  73 
Rhamnose,  59,  65,  66 

,  relation    to    glycogen    for- 
mation, 213 
Rhodizonic  acid,  370 
Rhodophan,  399 
Rhodopsin,  398 
Rhubarb,    action    on    the    urine,    530, 

544 
Rib-cartilage,  347 
Ribose,  66 

Rigor  mortis  of  the  muscles,  375,  388 
Ring  faeces,  321 
Roberts'  method  for  estimating  sugar, 

553 
Rodents,  bile-acids  of,  227,  241 
Rods  of  the  retina,  pigments  of,  398 
Rosenbach's  urine  test,  495 
Rovida's    hyaline    substance,    91,    129, 

150,  199,  403 
Rye  bread,  consumation  in  the  intes- 
tine, 331,  334 

Saccharic  acid,  61,  506 

,  relation     to    glycogen 
formation,  214 
Saccharin,  relation  to  glycogen  forma- 
tion, 214 
Saccharogen  in  the  mammary  glands, 

443 
Salicylic  acid,  action  on  pepsin  diges- 
tion, 270 
,  action    on    metabolism, 
643 


Salicylic   acid,   action   on    trypsin    di- 
gestion, 301 
,  behavior  in  the  animal 
body,  528 
Saliva,  251—261 

,  secretion  of,  259,  260 

,  mixed,  254 

,  physiological     importance     of,, 

260 
,  behavior  in  the  stomach,  260,, 

278,  309 
,  various  kinds  of,  252,  253,  254 
,  action  of,  257,  258 
,  composition  of,  259 
Salivary  calculi,  261 
Salivary  diastase.     £ee  Ptyalin. 
Salivary  glands,  251 
Salmon,  flesh  of,  387 

,  sperma  of,  405,  406 
Saltpetre,  action  on  metabolism,  643 
Salts,  absorption  of,  339.     See  also  the 

various  salts. 
Salt-plasma,  112 
Salts  of  vegetable  acids,  behavior  in 

the  organism,  449 
Samandarin,  579 

Santonin,  action  on  the  urine,  530,  544 
Saponification  of  neutral  fats,  82,  85, 

298,  310,  338 
Sarcolactic  acid.     See  Paralaetic  acid.. 
Sarcolemma,  360 
Sarcosin,  366 

,  behavior      in      the      animal 
body,  523 
Sarkin.     See  Hypoxanthin. 
Schreiner's  base,  404 
Schvi'eitzer's  reagent,  79 
Sclerotica,  402 
Scyllit,  201 
Sebacic  acid,  85 
Sebum,  578 

Sedimentum  lateritium,  447,  478,   504 
Sediments.     See  Urinary  sediments. 
Semen,  403 
Semiglutin,  55 
Seminose.     See  Mannose. 
Senna,  action  on  the  urine,  530,  544 
Seralbumin,  18,  120 


INDEX. 


eyi^ 


Seralbumin,  detection    in     the     urine, 
535 
,  quantitative      estimation, 

122.  536 
,  behavior    in    the    animal 
body,  121,  415 
Serglobulin,  18,  119 

,  importance     in     the     co- 
agulation of  the  blood, 
157 
,  detection    in    the    urine, 

534 
,  quantitative     estimation, 
120,  536 
Sericin,  18,  57 
Sericoin,  37 
Serin,  57 

Serous  fluids,  188—197 
Serum.     See  Blood-serum. 
Serum  casein.     See  Serglobulin. 
Sharks,  bile  of,  225,  238 

,  urea  in  bile  of,  452 
Sheep-milk,  434 
Shell-membrane  of  the  hen's  egg,  49, 

416 
Silicic  acid  in  feathers,  573 
in  urine,  519 

in  the  hen's  egg,  413,  416, 
418 
Silk  gelatin,  57 
Sinkalin,  93 
Sinistrin,  animal,  48 
Skatol,  22,  314,  315 

,  formation  in  putrefaction,  22, 

314,  489,  496 
,  behavior  in  the  animal  body, 
314,  489,  496,  529 
Skatol-acetic  acid,  23 
Skatol-amido-acetic  acid,  23 
Skatol-carbonic  acid,  496 
Skatol-pigment,  496 
Skatoxyl,  315,  496 
Skatoxyl-glycuronic  acid,  496,  529 
Skatoxyl-sulphuric  acid,  489,  496 

in  sweat,  581 
Skeletins,  56 

Skeleton  at  various  ages,  350 
Skin,  573—582 


Skin,  excretion  through  the,  578,  579 

—582,  609—613 
Sleep,  metabolism  in,  650 
Smegma  prseputii,  579 
Snail  mucin,  45 
Snake  poison,  15 
Soaps  in  blood-serum,  123 
in  chyle,  183,  335 
in  pus,  199 
in  faeces,  321,  322,  338 
in  bile,  225,  238 
,  importance    in    the    emulsifica- 
tion  of  the  fats,  298,  311,  338 
Sodium  alcoholate  as  a  saponification 

agent,  86 
Sodium  bicarbonate,  action  on  the  se- 
cretion of  pancreatic  juice,  295 
Sodium    chloride,  elimination    by    the 
urine,     127,     509,. 
510 
,  elimination    by    the 

sweat,  581 
,  physiological  impor- 
tance, 627,  628 
,  quantitative     e  s  t  i- 
mation,     510 — 512 
,  influence      on      the 
quantity  of  urine, 
642 
,  influence      on      the 
elimination         o  f 
urea,  643 
,  influence      on      the 
secretion    of    gas- 
tric juice,  274 
,  influence      on      the 
secretion    of    pan- 
creatic  juice,   295 
,  influence  on  absorp- 
tion, 340 
J  behavior    with    food 
rich  in  potash,  628 
J  insufficient      supply 

of,  127,  274 
,  action  on  pepsin  di- 
gestion, 270 
,  action     on     trypsin 
digestion,  301 


700 


INDEX. 


Sodium  combinations,  elimination  by 

the  urine,  517 
Sodium  combinations,  division  among 

the  form  elements  and  fluids,  109 
Sodium    combinations.     See    also    the 

various   tissues   and  fluids. 
Sodium  fluoride,   antiseptic  action  of, 

11 
Sodium  idodide,  absorption  of,  339 
Sodium  phosphate   in  the  urine,   448, 
513 
,  action  on  metabo- 
lism, 643 
Sodium  salicylate,  action  on  secretion 

of  bile,  224 
Sodium  sulphate,  absorption  of,  340 

,  action     on     proteid 
metabolism,   643 
Soldiers,  diet  of,  656,  657 
Source  of  muscular  energy,  384,  385 
Sparing  theory,  215 
Specific  rotation,  64 
Spectrophotometry,  147,  148 
Sperma,  403 
Spermaceti,  86 
Spermaceti  oil,  86 
Spermatin,  406 
Spermatocele  fluids,   194 
Spermatozoa,  404,  405 
Spermin,  404 
Spermin  crystals,  404 
Sputum,  605,  606 

Spider  excrement,  guanin  therein,  105 
Spider  poison,  15 
Spiegler's  reagent,  533 
Spirographin,  47 
Spirogyra,  109 
Spleen,  200—203 

,  relation    to    blood    formation, 

202 
,  relation    to    uric-acid    forma- 
tion, 202,  475,  476 
,  relation  to  digestion,  202 
,  blood  of,  170 
,  pulp  of,  475 
Splitting  processes,  in  general,  1,  2,  9. 
See  also  the   various   enzymes   and 
ferments. 


Spongin,  18,  57 

Spongioplasm,  90 

Staphylococcus,  behavior  with  gastric 

juice,  282 
Starch,  75 

,  hydrolytic   cleavage  by   intes- 
tinal juice,  290 
,  hydrolytic    cleavage    by    pan- 
creatic juice,  297 
,  hydrolytic  cleavage  by  saliva, 

256,  257 
,  caloric  A^alue  of,  617 
,  absorption  of,  332,  334 
,  behavior  in  the  stomach,  276 
Starch  cellulose,  76 
Starch  granulose,  76 
Starvation,  action  on  blood,  172,  177 
,  action    on    bile    secretion, 

223 
,  action  on  urine,  318,  453, 

467,  473,  486,  494,  517 
,  action   on    elimination    of 

indican,  317 
,  action     on     secretion     of 

pancreatic  juice,  295 
,  action    on    elimination    of 

phenol,  317 
,  action      on      metabolism, 

615,  616—619 
,  quantity    of    nitrogen    in 

excrements  in,  611 
,  death  from,  619 
Starvation  cures,  658,  659 
Steapsin,  298 
Stearic  acid,  83 
Stearin,  83 

,  absorption  of,  335 
Stercobilin,  234,  322 
Stethal,  86 

Stomach,  importance  in  digestion,  281, 
282 
,  self-digestion  of,  282,  283 
,  digestion  in,  276—283 
Stomachic  glands,  261 
Streptococcus,    behavior    with    gastric 

juice,  282 
Stromafibrin,  129 
Stroma  of  the  blood-corpuscles,  129 


INDEX. 


701 


Stroma  of  the  muscle,  365 

Struma  cystica,  204 

Strychnin,  passage  of,  into  the  urine, 

530 
Sublingual  gland,  251 
Sublingual  saliva,  253 
Submaxillary  gland,  251 
Submaxillary  mucin,  45 
Submaxillary  saliva,  252 
Succinic  acid  in  intestine,  313 
in  the  spleen,  201 
in     transudations,     191, 

195 
in  the  thyroid  gland,  204 
passage     of,     into     the 

urine,  505 
passage     of,     into     per- 
spiration, 581 
Sugar,  absorption  of,  332—334,  340 

,  syntheses  of  varieties  of  sugars, 

61,  62,  66 
,  relation   to   muscular  activity, 
379,  380,  384 
See  also   the  various  varieties 
of  sugars. 
Sugar  formation  with  lack  of  oxygen, 
372 
in     the     liver,     217, 

218,  293,  294 
after    extirpation    of 
the   pancreas,   221, 
293,  294 
Sugar  tests  in  the  urine,  544 — 549 
Sulphocyanides  in  the  urine,  507 
Sulphonal  intoxication,  urine  in,  540 
Sulphur   in   proteid   bodies,    19 
in  the  urine,  507,  508 
,  elimination  of,  during  work, 

383,  508 
,  neutral     and     acid,     in     the 

urine,  508 
,  behavior    in    the    organism, 
508,  509 
Sulphur  methsemoglobin,   139 
Sulphuretted    hydrogen    in    putrefac- 
tion in  the  intestine,  314,  316 
Sulphuretted  hydrogen  in  the  urine, 
508 


Sulphuric  acid,  ethereal  and  sulphate 
in    the    urine,    489, 
490,  516 
,  elimination  of,  during 

work,  383 
,  elimination  of,  by  the 

urine,  448,  515 
,  elimination  of,  by  the 

sweat,   580,  581 
,  estimation  of,  516 
,  relation     to     elimina- 
tion     of      nitrogen, 
515,  612 
Suprarenal  capsule,  205 

,  bile-acids    therein, 
243 
Sweat,  579—581 

,  excretion  of,  579 
,  action  on  the  urine,  448,  451, 
521 
Swimming-bladder  of  fishes,  gases  of, 

603 
Swimming-bladder    of    fishes,    guanin 

of,  105 
Sympathetic  saliva,  252 
Synovial  fluid,  196 
Synovin,  196 
Syntheses,  1,  2,  6 

of  ethereal  sulphuric  acids, 
314,    489,    493,   494,    496, 
529, 
of     conjugated     glycuronic 
acids,  491,  496,  506,  524, 
529 
of  uric  acid,  471,  472,  475 
of  urea,  452,  456 
of  hippuric  acid,  3,  486 
of  varieties  of  sugars,  63,  66 
in  the  liver,  206, 215,456,475 
Syntonin,  32,  365 

,  caloric  value  of,  618 

Talonic  acid.  72 
Talose,  66,  72 
Tapeworm  cyst,  196 
Tartar,  261 

Tartaric    acid,    relation    to    glycogen 
formation,  214 


702 


INDEX. 


Tartaric    acid,    passage    of,    into    the 

sweat,  581 
Tatalbumin,  413 
Taurin,  231 

,  behavior  in  the  animal  body, 
523,  524 
Tauro-carbamic  acid,  523 
Taurocholic  acid,  227 

,  quantity    in    differ- 
ent biles,  240,  241 
,  occurrence     in     me- 
conium, 323 
,  decomposition        i  n 
the  intestine,   317 
Tea,  action  on  metabolism,  644 
Tears,  402 
Teeth,  353 

Teichmann's  crystals,  142,  539 
Tendon  mucin,  45,  342 
Tendon  synovia,  196 
Tension  of  the  CO    in  the  blood,  600— 

2 

603 

in  the  tissues,  603 
in  the  lymph,  182 
O  in   the    blood,    593 
—599 
Terpen-glycuronic  acid,   529 
Turpentine,  action  on  the  secretion  of 
bile,  224 
,  action  on  the  urine,  529, 

530 
,  behavior    in    the    animal 
body,  529 
Tetanin,  14 

Tetronerythrin,  148,  578 
Testis,  403 
Tewiikose,  428 

Thallin,  action  on  the  urine,  530 
Theobromin,   102 
Theophyllin,  102 
Thiolactic  acid,  50 
Thiophen,  524 
Thiophenic  acid,  524 
Thiophenuric  acid,  524 
Thrombin,  116,  157,  159,  160 
Thrombosin,  118,  159 
Thymin,  100 
Thyminic  acid,  100 


Thymus,  203 

Thyreoidea,  204 

Thyroid  gland,  204 

Thyreoproteine,  204 

Tissue-fibrinogen,  91,  102,  161 

Toluhydrochinon,  498 

Toluol,  behavior  in  the  animal  body, 

486,  526 
Toluric  acid,  528 

Toluylendiamin,  poisoning  with,  247 
Toluylic  acid,  528 
Tonus,  chemical,  of  the  muscle,  377 
Tooth  tissue,  353,  625 
Tortoise,  bones  of,  349 
Tortoise-shell,  49 
Toxalbumins,  16,  42 
Toxins,  14,  206 

Tl-ansfusion  of  blood,  173,  178 
Transudations,  180,  188—197,  592 
Transudation  into  the  intestine,  324 
Trehalose,  75 
Tribromacetic  acid,  24 
Tribrom-amido-benzoic  acid,  24 
Tricalcium  casein,  425 
Trichlor-acetic    acid     as    reagent,    27, 

213 
Trichlor-butyl  alcohol,  behavior  in  the 

animal  body,  524 
Triehlor-butyl-glycuronic  acid,  524 
Trichlor-ethyl-glycuronie     acid.        See 

Uroehloralic  acid. 
Trinitro-albumin,  24 
Triolein,  84 
Tripalmitin,  83 

Triple  phosphate  in  urinary  sediments, 
566,  568 
in     urinary     calculi, 
569,  570 
Tristearin,  83 
Trommer'e  test  for  sugar,  69,  546 

test     for     sugar,     behavior 

Avith  glycuronie  acid,  507 

test     for     sugar,     behavior 

with  uric  acid,  478 
test    for    sugar,    behavior 
with  creatinin,  469 
Trypsin,  296,  299 

,  action  on  proteids,  301 


INDEX. 


703 


Trypsin,  action  on  other  bodies,  307 
Trypsin  digestion,  21,  301 

,  action    of    various 
conditions  on,  301 
,  products  of,  302 
Trypsin  zymogen,  299,  308 
Trytophan,  22,  302 
Tubercle  virus,  behavior  with  gastric 

juice,  282 
Tuberculin,  43 
Tubo-ovarial  cysts,  409 
Tunicin,  574 
Turacin,  577 
Turacoverdin,  578 
Typhotoxin,  14 
Tyrosin,  304 

in  the  urine,  562 
in  sediments,  562,  568 
,    detection  of,  305,  568 
,    origin  of,  21,  22,  302,  314 
,    behavior      in      putrefaction, 

314,  487,  489,  498 
,   behavior      in  *  the      animal 
body,  526,  527 
Tyrosin-sulphuric  acid,  305 

Uraemia,  blood  in,  176 
,  bile  in,  241 
,  gastric  contents  in,  283 
,  sweat  in,  581 
Uramido-aeids,  523  ■ 

Uramido-benzoic  acids,  528 
Urates,  478 

in  sediments,  447,  564,  565 
Urea,  452 

elimination   in    work   and   rest, 

382,  384,  385 
elimination   in    starvation,    452, 

621 
elimination  in  children,  454,  647 
elimination      in      disease,      453, 

458,  517,  518 
elimination  after  different  foods. 
452,   630,   631,   632,   637,    638, 
642,  644 
,  progress  of  elimination  after  a 

meal,  635 
,  properties  and  reactions,  459 


Urea,  formation  and  origin,  451 — 459 
,  quantitative    estimation,    461 — 

467 
,  cleavage  by  ferments,  459,  565 
,  synthesis  of,  452,  454 — 456 
,  occurrence    in    blood,    124,    170, 

171 
,  occurrence  in  bile,  238,  241 
,  occurrence    in    vitreous    humor, 

400 
,  occurrence    in    the    liver,    455, 

457,  458 
,  occurrence  in  muscles,  366 
Urea  nitrate,  460 
Urea  oxalate,  460 
Ureometer,  Esbach's,  466 
Urethan.      See     Carbamic-acid     ethyl- 
ester,  467 
Uric  acid,  471 

,  relation  to  urea,  471,  475 
,  properties     and     reactions, 

477—479 
,  formation  in  the  organism, 
474—477 
from  ammonia,  474 
,  relation      to      leucocytosis, 

475 
,  relation  to  the  spleen,  202, 

475,  476 
,  quantitative        estimation, 
479—481 
synthesis  of,  471 
,  behavior  in  the  body,  474, 

483 
,  occurrence,  472 
,  occurrence    in    the    sweat, 

581 

« 

,  occurrence     in     sediments, 
447,  564,  568 
Uric-acid  calculi,  569 
Uricacidfemia,   176 
Urinary  calculi,  568 — 572 
I'rinary  pigments,  499 — 505,  540,  541 

,  medicinal,  544 
Urinary  sand,  568 
Urinary  sediments,  447,  566—568 
Urine,  445 — 572 

,  excretion  of,  519 — 522 


704 


INDEX. 


XJrjne,  constituents,    anorganic,    509 — 
519 
constituents,  poisonous,  509 
constituents,     organic,     patho- 
logical, 531—564 
constituents,   physiological,  452 

—509 
constituents,  casual,  522 — 530 
color  of,  447,  499,  500,  522,  530, 

538,  541—544 
solids,     calculation     of     their 

quantity,  521 
solids,  percentage  of  same,  522 
alkaline      fermentation,      459, 

505,  565 
acid  fermentation,  564 
gases  of,  519 
quantity  of,  519—522 
physical    properties    of,    445 — 

452 
reaction  of,  447—451,  459,  460 
degree  of  acidity,  448 
determination     of     degree     of 

acidity,  449 
specific  gravity,  451,  452,  521, 

522 
specific  gravity,  determination 

of  same,  451 
passage  of  foreign  bodies  into, 

522—530 
composition  of,  522 
Urine  indican,  493 
Urine  indigo,  493,  496 
Urine  poison,  509 

Urine  stones.     See  Urinary  calculi. 
Urine  sugar.     See  Dextrose. 
Urinometer,  451 
Urobilin,  499,  500—504 

,  relationship      to      bilirubin, 

234,  245,  500 
,  relationship     to      choletelin, 

501 
,  relationship  to  hsematin,  245 
,  relationship    to    haematopor- 

phyrin,  501 
,  relationship    to    hydrobiliru- 
bin,  234,  323,  500 
Urobilin  icterus,  502 


Urobilinogen,  499,  500 

Urobilinoidin,  501 

Urocanic  acid,  509 

Urochloralic  acid,  506,  524 

Urochrom,  504 

Urocyanin,  500 

Uroerythrin,  504,  541 

Urofuscohaematin,  541 

Uroglaucin,  500 

Urohaematin,  500 

Uroleucic  acid,  497,  499 

Uromelanins,  500 

Uronitro-toluolic  acid,  529 

Urophsein,  500 

Urorubin,  500 

Urorubrohaematin,  541 

Urorosein,  500,  541 

Urostealith,  571 

Uroxanthin,  493 

Urohodin,   500 

Ureids,  20,  471,  472,  483 

Uterine  milk,  419 

Utilization  of  foods,  330,  332,  335 

Valerianic  acid,  21,  354 
Varnishing  the  skin,  582 
Vegetable  gums,  77,  79 
Vegetable  mucilage,  77,  79 
Vegetable  myosin,  42 
Vegetable  proteids,  42 
Vegetarians,  food  of,  639,  654 

,  excrements  of,  321 
Venesection,  168,  176 
Vernix  caseosa,  578 
Vesicatory  blisters,  contents,  196 
Visual  purple,  398 
Visual  red,  398 
Vitellin,  18 

in  yolk  of  egg,  410 

in  protoplasm,  91 
Vitellolutein,  412 
Vitellorubin,  412 
Vitelloses,  36 
Vitreous  humor,  343,  400 

Water  drinking,  action  on  the  elimi- 
nation of  chlo- 
rideSj  510 


INDEX. 


705 


Water  drinking,  action  on  the  elimi- 
nation      of      uric 
acid,  473 
,  action  on  the  elimi- 
nation     of      urea, 
642 
,  action  on  the  deposi- 
tion of  fat,  642 
,  action  on  the  secre- 
tion of  urine,  520, 
521 
Water  elimination  by  the  urine,   520 
—522,  609,  610 
elimination  by  the  skin,  579, 

610 
elimination  in  starvation,  623 
,  importance     for     the     animal 

body,  625 
,  quantity    of,    in    the    various 

organs,  623 
,  lack  of,  in  the  food,  623 
,  absorption  of,  339 
Wax,  87 

in  plants,  579 
Weyl's  reaction  for  creatinin,  469 
Wheat  bread,  absorption  of,  334 
Whey,  422 
Whey  proteid,  427 
White  of  egg,  413 

,  calorific  value,  574 
Witch's  milk,  439 

Woman's  milk.     See  Human  milk. 
Wool-fat,  250,  579 

Work,  action  on  chlorine  elimination, 
510 
,  action  on  elimination  of  phos- 
phoric acid,  513 
,  action   on    elimination   of   sul- 
phuric acid,  383,  508 
,  action    on   the   need   for   food, 
65G,  657 


Work,  action  on  metabolism,  377,  383 

—385 
Xanthin,  104 

in  the  urine,  484 
in  urinary  sediments,  568 
,  quantity  in  the  liver,  208 
,  quantity    in     the     pancre-.s, 

292 
,  detection    and    quantitative 
estimation,  108,  109 
Xanthin  bases,  in  general,  102 

,  relationship     to     uric- 
acid  formation,  203, 
475 
,  behavior   to   muscular 

activity,   382 
,  occurrence       in       the 

blood,   103 
,  occurrence       in       the 
urine,  484 
Xanthin  calculi,  571 
Xantho-creatinin,  369,  381,  470 
Xanthophan,  399 
Xanthoproteic  acid,  24 
Xanthoproteic  acid,  reaction,  27 
Xylol,   behavior   in   the   animal   body, 

527 
Xyloses,  65,  66 

,  relation   to   glycogen    forma- 
tion, 213 

Yeast-cells,  proteids  in,  48 
Yolk  of  the  hen's  egg,  410 

Zinc  in  the  bile,  238 
in  the  liver,  210 
,  passage  of,  into  milk,  443 
Zoofulvin,  578 
Zoonerythrin,  578 
Zoorubin,  578 

Zymogens.     See  the  various  enzymes. 
Zymoplastic  substances,  157,  162 


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"        De  Pontibus  (a  Pocket-book  for  Bridge  Engineers). 

16mo,  morocco, 

Wood's  Construction  of  Bridges  and  Roofs 8vo, 

Wright's  Designing  of  Draw  Spans.     Parts  I.  and  II.. Svo,  each 

"  "  "      "  "  Complete Svo, 

4 


2  50 

10  00 

4  00 

3  00 

2  00 

2  50 

3  50 

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Qualitative — Quantitative— Organic — Inorganic,  Etc. 

Adriauce's  Laboratory  Calculations 12mo,     $1  25 

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Fuertes's  Water  and  Public  Health 12mo,  1  50 

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5 


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Thurston's  Stationary  Steam  Engines  for  Electric  Lighting  Pur- 
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Tillman's  Heat Svo,  1  50 

ENGINEERING. 

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{See  also  Bridges,  p.  4 ;  Hydraulics,  p.  9 ;  Materials  of  En- 
gineering, p.  10 ;  Mechanics  and  Machinery,  p.  12  ;  Steam 
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Baker's  Masonry  Construction Svo,  5  00 

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Black's  U.  S.  Public  Works Oblong  4to,  5  00 

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"       Inspection  of  Materials  and  Workmanship 16mo,  3  00 

Carpenter's  Experimental  Engineering  Svo,  6  00 

7 


Church's  Mechanics  of  Engineeriug — Solids  and  Fluids 8vo,  $6  00 

' '        Notes  and  Examples  iu  Mechanics 8vo,  2  00 

Crandall's  Earthwork  Tables 8vo,  1  50 

' '          The  Transition  Curve 16mo,  morocco,  1  50 

*  Dredge's  Penn.  Railroad  Construction,  etc.  .  .  Folio,  half  mor.,  20  00 

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Eissler's  Explosives — Nitroglycerine  and  Dynamite 8vo,  4  00 

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Fowler's  Coffer-dam  Process  for  Piers 8vo.  2  50 

Gerhard's  Sanitary  House  Inspection 12mo,  1  00 

Godwin's  Railroad  Engineer's  Field-book 16mo,  morocco,  2  50 

Gore's  Elements  of  Geodesy 8vo,  2  50 

Howard's  Transition  Curve  Field-book., . .  .12mo,  morocco  flap,  1  50 

Howe's  Retaining  Walls  (New  Edition.) 12mo,  1  25 

Hudson's  Excavation  Tables.     Vol.  II 8vo,  1  00 

Hutton's  Mechanical  Engineering  of  Power  Plants 8vo,  '  5  00 

Johnson's  Materials  of  Construction Large  8vo,  6  00 

"         Stadia  Reduction  Diagram.  .Sheet,  22 J  X  28^  inches,  50 

"         Theory  and  Practice  of  Surveying Small  8vo,  4  00 

Kent's  Mechanical  Engineer's  Pocket-book 16mo,  morocco,  5  00 

Kiersted's  Sewage  Disposal 12mo,  125 

Mahan's  Civil  Engineering.      (Wood.) 8vo,  5  00 

Merriman  and  Brook's  Handbook  for  Surveyors. . .  .16mo,  mor.,  2  00 

Merriman's  Geodetic  Surveying .8vo,  2  00 

"          Retaining  Walls  and  Masonry  Dams 8vo,  2  00 

"         Sanitary  Engineering 8vo,  2  00 

Nagle's  Manual  for  Railroad  Engineers 16mo,  morocco,  3  00 

Pattou's  Civil  Engineering ..8vo,  7  50 

"       Foundations 8vo,  5  00 

Pratt  and  Alden's  Street-railway  Road-beds 8vo,  2  00 

Rockwell's  Roads  and  Pavements  in  France 12mo,  1  25 

Riiffner's  Non-tidal  RiverS: 8vo,  1  25 

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Smith's  Wire  Manufacture  and  Uses Small  4to,  3  00 

Spalding's  Roads  and  Pavements 12mo,  2  00 


1  50 

5  00 

5  00 

25 

2  00 

2  50 

3  00 

6  00 

6  50 

2  50 

1  00 

5  00 

5  00 

4  00 

3  00 

Spaldiug's  Hydraulic  Cement JH'CAE 12mo,     $2  00 

Taylor's  Prismoidal  Formulas  and  Earthwork 8vo, 

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Wait's  Engineering  and  Architectural  Jurisprudence 8vo, 

Sheep, 

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Warren's  Stereotomy — Stone-cutting 8vo, 

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Wood's  Theory  of  Turbines 8vo,  2  50 


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Alleu's  Tables  for  Iron  Analysis 8vo,  $8  00 

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Bolland's  Encyclopaedia  of  Founding  Terms 12mo,  3  00 

The  Iron  Founder 12mo,  2  50 

"          "       "          "        Supplement 12mo,  2  50 

Bouvier's  Handbook  on  Oil  Painting 12mo,  2  00 

Eissler's  Explosives,  Nitroglycerine  and  Dynamite 8vo,  4  00 

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Metcalf 's  Steel— A  Manual  for  Steel  Users 12mo,  2  00 

*Reisig's  Guide  to  Piece  Dyeing. Svo,  25  00 

Spencer's  Sugar  Manufacturer's  Handbook. . .  .16mo,  mor.  flap,  2  00 
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16mo,  mor.  flap,  3  00 

Thurston's  Manual  of  Steam  Boilers Svo,  5  00 

Walke's  Lectures  on  Explosives Svo,  4  00 

West's  American  Foundry  Practice 12mo,  2  50 

' '      Moulder's  Text-book  12mo,  2  50 

Wiechmann's  Sugar  Analysis Small  Svo,  2  50 

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MATERIALS  OF  ENGINEERING. 

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Baker's  Masonry  Construction Svo,      5  00 

Beardslee  and  Kent's  Strength  of  Wrought  Iron Svo, 

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Burr's  Elasticity  and  Resistance  of  Materials Svo, 

Byrne's  Highway  Construction Svo, 

Church's  Mechanics  of  Engineering — Solids  and  Fluids Svo, 

Du  Bois's  Stresses  in  Framed  Structures Small  4to, 

Johnson's  Materials  of  Construction Svo, 

Lanza's  Applied  Mechanics. , Svo, 

Marteus's  Materials.     (Henning.) Svo.     {In  the  press.) 

Merrill's  Stones  for  Building  and  Decoration Svo, 

Merriman's  Mechanics  of  Materials Svo, 

"  Strength  of  Materials 12ino, 

Pattou's  Treatise  on  Foundations Svo, 

Rockvi^ell's  Roads  and  Pavements  In  France 12rao, 

ling's  Roads  and  Pavements 12mo,       2  00 

10 


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5 

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5 

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6 

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7  50 

5  00 

4  00 

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Thurston's  Materials  of  Construction 8vo,  $5  00 

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Wood's  Resistance  of  Materials 8vo,  2  00 

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Cliapman's  Theory  of  Equations 12mo, 

Compton's  Logarithmic  Computations 12mo, 

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Halsted's  Elements  of  Geometry ...8vo, 

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Johnson's  Curve  Tracing 12mo, 

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Small  8vo, 

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Merriman  and  Woodward's  Higher  Mathematics 8vo, 

Merriman's  Method  of  Least  Squares 8vo, 

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1 

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1 

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1 

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4  00 

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3 

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75 

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Warren's  Problems  and  Theorems. 8vo,  $2  50 

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Metcalfe's  Cost  of  Manufactures 8vo,       5  00 

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Robinson's  Principles  of  Mechanism 8vo,       3  00 

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3  00 

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1  00 

75 

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Warren's  Machine  Construction 2  vols.,  8vo,  7  50 

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*  "            "                Steel,  Fuel,  etc 8vo,  15  00 

Kunhardi's  Ore  Dressing  in  Europe 8vo,  1  50 

Metcalf's  Steel— A  Manual  for  Steel  Users 12mo,  2  00 

O'Driscoll's  Treatment  of  Gold  Ores 8vo,  2  00 

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Barringer's  Minerals  of  Commercial  Value — Oblong  morocco, 

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Brush  and  Pen  field's  Determinative  Mineralogy.    New  Ed.  Svq, 

Chester's  Catalogue  of  Minerals 8vo, 

"  "  «'        "         Paper, 

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Dana's  American  Localities  of  Minerals 8vo, 

"      Descriptive  Mineralogy.     (E.  S.) 8vo,  half  morocco, 

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■'      Minerals  and  How  to  Study  Them.     (E.  S.). 12mo, 

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4to,  lialf  morocco,     25  00 
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Egleston's  Catalogue  of  Minerals  and  Synonyms 8vo,  $3  50 

Eissler's  Explosives — Nitroglycerine  and  Dynamite 8vo,  4  00 

Hussak's  Rock-forming  Minerals.     (Smith.) Small  8vo,  2  00 

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Kunbardt's  Ore  Dressing  in  Europe Svo,  1  50 

O'Driscoll's  Treatment  of  Gold  Ores Svo,  2  00 

*  Penfield's  Record  of  Mineral  Tests Paper,  Svo,  50 

Rosenbusch's    Microscopical    Physiography  of    Minerals    and 

Rocks.     (Iddiugs.) Svo,  5  00 

Sawyer's  Accidents  in  Mines '. Large  Svo,  7  00 

Stockbridge's  Rocks  and  Soils Svo,  2  50 

Walke's  Lectures  on  Explosives Svo,  4  00 

Williams's  Lithology Svo,  3  00 

Wilson's  Mine  Ventilation .16mo,  1  25 

"        Hydraulic  and  Placer  Mining 12mo,  2  50 

STEAM  AND  ELECTRICAL  ENGINES,  BOILERS,  Etc. 

Stationakt — Marine— Locomotive — Gas  Engines,  Etc. 
(See  also  Engineering,  p.  7.) 

Baldwin's  Steam  Heating  for  Buildings 12mo,  2  50 

Clerk's  Gas  Engine Small  Svo,  4  00 

Ford's  Boiler  Making  for  Boiler  Makers ISmo,  1  00 

Hemenway's  Indicator  Practice 12mo,  2  00 

Hoadley's  Warm-blast  Furnace Svo,  1  50 

Kneass's  Practice  and  Theory  of  the  Injector Svo,  1  50 

MacCord's  Slide  Valve Svo,  2  00 

Meyer's  Modern  Locomotive  Construction 4to,  10  00 

Peabody  and  Miller's  Steam-boilers Svo,  4  00 

Peabody's  Tables  of  Saturated  Steam Svo,  1  00 

"         Thermodynamics  of  the  Steam  Engine Svo,  5  00 

"         Valve  Gears  for  the  Steam-Engine Svo,  2  50 

Pray's  Twenty  Years  with  the  Indicator Large  Svo,  2  50 

Pupin  and  Osterberg's  Thermodynamics 12mo,  1  25 

Reagan's  Steam  and  Electric  Locomotives 12mo,  2  00 

Rbntgen's  Thermodynamics.     (Du  Bois.) Svo,  5  00 

Sinclair's  Locomotive  Running 12mo,  2  00 

Snow's  Steam-boiler  Practice Svo.     {In  the  press.) 

Thurston's  Boiler  Explosions 12mo,  1  50 

"           Engine  and  Boiler  Trials Svo,  5  00 

"  Manual  of  the  Steam  Engine.      Part  L,  Structure 

and  Theoiy Svo,  6  00 

"  Manual  of  the   Steam  Engine.     Part  XL,   Design, 

Construction,  and  Operation Svo,  6. 00 

2  parts,  10  00 
14 


Thurstou's  Philosophy  of  the  Steam  Engine 12mo,  $    75 

"  Reflection  on  the  Motive  Power  of  Heat.    (Carnot.) 

13mo,  1  50 

'*           Stationary  Steam  Engines 13mo,  1  50 

"           Steam-boiler  Construction  and  Operation 8vo,  5  00 

Spangler's  Valve  Gears 8vo,  2  50 

Weisbach's  Steam  Engine.     (Du  Bols.) 8vo,  5  00 

Whitham's  Constructive  Steam  Engineering Bvo,  10  00 

"           Steam-engine  Design 8vo,  5  00 

Wilson's  Steam  Boilers.     (Fluther. ) 12mo,  2  50 

Wood's  Thermodynamics,  Heat  Motors,  etc 8vo,  4  00 

TABLES,  WEIGHTS,  AND  MEASURES. 

For  Actuaries,  Chemists,  Engineers,  Mechanics— Metric 
Tables,  Etc 

Adriance's  Laboratory  Calculations 12mo,  1  25 

Allen's  Tables  for  Iron  Analysis 8vo,  3  00 

Blxby's  Graphical  Computing  Tables Sheet,  25 

Compton's  Logarithms 12mo,  1  50 

Crandall's  Railway  and  Earthwork  Tables 8vo,  1  50 

Egleston's  Weights  and  Measures 18mo,  75 

Fisher's  Table  of  Cubic  Yards Cardboard,  25 

Hudson's  Excavation  Tables.     Vol.  H 8vo,  100 

Johnson's  Stadia  and  Earthwork  Tables , 8vo,  1  25 

Ludlow's  Logarithmic  and  Other  Tables.     (Bass.) 12mo,  2  00 

Totteu's  Metrology 8vo,  2  50 

VENTILATION. 

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Beard's  Ventilation  of  Mines 12mo,  2  50 

Carpenter's  Heating  and  Ventilating  of  Buildings 8vo,  3  00 

Gerhard's  Sanitary  House  Inspection Square  16mo,  1  00 

Mott's  The  Air  We  Breathe,  and  Ventilation 16mo,  1  00 

Reid's  Ventilation  of  American  Dwellings 12mo,  1  50 

Wilson's  Mine  Ventilation 16mo,  1  25 

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Alcott's  Gems,  Sentiment,  Language Gilt  edges,  5  00 

Bailey's  The  New  Tale  of  a  Tub 8vo,  75 

Ballard's  Solution  of  the  Pyramid  Problem Bvo,  1  50 

Barnard's  The  Metrological  System  of  the  Great  Pyramid.  .8vo,  1  50 

Davis's  Elements  of  Law 8vo,  2  00 

15 


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Ferrel's  Treatise  ou  the  "Winds 8vo,  4  00 

Haines's  Addresses  Delivered  before  the  Am.  Hy.  Assn.  ..12mo.  2  50 

Mott's  The  Fallacy  of  the  Present  Theory  of  Sound . .  Sq.  16mo,  1  00 

Perkins's  Cornell  University Oblong  4to,  1  50 

Ricketts's  History  of  Rensselaer  Polytechnic  Institute 8vo,  3  00 

Rotherham's    The    New    Testament     Criticallj^    Emphasized. 

13mo,  1  50 
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Large  Svo,  2  00 

Totteu's  An  Important  Question  in  Metrology Svo,  3  50 

Whitehouse's  Lake  Moeris Paper,  35 

*  Wiley's  Yosemite,  Alaska,  and  Yellowstone 4to,  3  00 

HEBREW  AND  CHALDEE  TEXT=BOOKS. 

For  Schools  and  Theoi,ogical  Seminaries. 

Gesenius's  Hebrew  and   Chaldee  Lexicon  to  Old   Testament. 

(Tregelles.) Small  4to,  half  morocco,  5  00 

Green's  Elementary  Hebrew  Grammar 12mo,  1  25 

"       Grammar  of  the  Hebrew  Language  (New  Edition). Svo,  8  00 

"       Hebrew  Chrestomathy Svo,  3  00 

Letteris's   Hebrew  Bible  (Massoretic  Notes  in  English). 

Svo,  arabesque,  2  25 

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Hammarsten's  Physiological  Chemistry.    (Maudel.) Svo,  4  00 

Mott's  Composition,  Digestibility,  and  Nutritive  Value  of  Food. 

Large  mounted  chart,  1  25 

Ruddiman's  Incompatibilities  in  Prescriptions Svo,  2  00 

Steel's  Treatise  on  the  Diseases  of  the  Ox Svo,  6  00 

"      Treatise  on  the  Diseases  of  the  Dog Svo,  8  50 

Woodhull's  Military  Hygiene 16mo,  1  50 

Worcester's  Small  Hospitals — Establishment  and  Maintenance, 
including  Atkinson's  Suggestions  for  Hospital  Archi- 
tecture  12mo,  1  25 

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